Return to the home page...

Go Back   Moyer Marine Atomic 4 Community - Home of the Afourians > Discussion Topics > Fuel System

Reply
 
Thread Tools Display Modes
  #1   IP: 38.118.52.41
Old 06-13-2006, 04:30 PM
Don Moyer's Avatar
Don Moyer Don Moyer is offline
 
Join Date: Oct 2004
Posts: 2,807
Thanks: 0
Thanked 142 Times in 91 Posts
Fuel-Related Engine Shutdowns

From our Tech Tips section:

This tech tip is focused on the causes of fuel-related shutdowns, with a few suggestions for troubleshooting and remediation.

A good friend of ours from across the Chesapeake Bay had been experiencing regular engine shutdowns after motoring approximately 45 minutes to an hour, virtually every time he took his boat out. Finally, after much head-scratching, he discovered a pinhole in the canister of his primary fuel filter. It was not a RACOR filter, but it was of the same size and type as the RACOR filter and water separator shown in our online catalog. He replaced the fuel filter, and the shutdowns ceased.

The pin hole, though never manifesting as a fuel leak until my friend pressurized the filter, was apparently allowing enough air to be drawn into the fuel stream to form an air bubble which eventually reached the fuel pump and caused it to cavitate.

Around the same time that my friend had been sorting through his difficulties, Brenda and I acquired a small fishing boat to scoot around the tributary of the Chesapeake Bay that extends near our house. The boat has a small four-cylinder inboard gasoline engine, and incredibly enough, it was regularly shutting down every 20 minutes or so from what appeared to be fuel starvation, in much the same way that my friend's engine had been shutting off just a few weeks earlier.

I installed one of our new RACOR fuel filters soon after acquiring our little motor boat, and I had also installed a small rubber priming bulb between the tank (which is located lower than the engine on this boat) and the RACOR. The basic reason for the priming bulb is to prime the filter after replacing an element, without having to fill the canister with fuel and have it spill all over the engine compartment while I'm reinstalling the canister.

Much to my surprise, the first time I pressurized the RACOR and the rest of the fuel system with the priming bulb, two small pre-existing leaks showed up in fittings between the filter and the engine mounted mechanical fuel pump. The leaks were so small that I was never aware of their existence during normal operation, but they apparently allowed enough air to enter the fuel line under suction to shut down the engine for lack of fuel. The engine has never shut down since fixing the leaks.

I've been eagerly sharing these experiences with folks who have called in with fuel-related shutdowns over the past several weeks, and we've already had a few folks call back to report their own success stories in correcting small suction leaks in their fuel supply systems.

I'll try to consolidate and amplify a few key points:

1) Small leaks can apparently exist within a fuel supply system that will not manifest as fuel leaks, but which will allow enough air to be drawn into the lines to cavitate fuel pumps by the suction created during normal operation.

2) The high vapor pressure of gasoline exacerbates the problem of suction leaks by causing the air bubbles to enlarge somewhat after they form.

3) Electrical pumps seem to be somewhat more sensitive to the effects of air in lines than do mechanical pumps, although we have one recent case of fuel starvation caused by a leak above the sediment bowl in a mechanical pump.

4) Boats with tanks located lower than the top of the engine and at distances greater than 5 or 6 feet are more at risk of shutdowns from fuel starvation from small leaks in the system, due to the fact that more suction is created within their systems. Leaks in the fuel supply systems of boats with tanks higher and very close to the engine would probably manifest as fuel leaks and quickly be detected.

5) Air can be also be introduced into fuel supply systems while changing filter elements, and/or other maintenance, which will cavitate pumps, usually after a few minutes of running. Again, electric pumps are more at risk than mechanical pumps, since electric pumps make very poor air compressors. It's sometimes possible to prime filters after an element change by working the priming lever of a well maintained mechanical pump, but electric pumps will frequently never prime until the air is removed in some other manner.

6) Installation of a rubber priming bulb between the tank and the primary fuel filter will enable you to prime the system after replacing a filter element (or other maintenance), as well as to pressurize the system to check for leaks. The bulb also provides a nice diagnostic tool when troubleshooting fuel problems in general, by providing a second method of producing fuel pressure. In normal operation, the fuel pump is able to draw fuel through the priming bulb with little or no measurable head loss being added.

These priming bulbs (commonly used in outboard fuel supplies) are available from West Marine for 1/4", 5/16" and 3/8" fuel hose. At approximately $12, they may represent the best value you'll ever encounter in terms of enhancing engine reliability.

7) Many boats still have small screens over the ends of their pickup tubes which become clogged quite easily, and are really unnecessary after the installation of a proper primary fuel/water separating type of primary filter.

8) Lastly, spring-loaded check valves used as anti-siphon devices sometimes cause or at least exacerbate problems. These valves are usually installed where the pickup tube leaves the top of the tank and function by adding more head loss (approximately 2 psi) than the weight of the fuel in the line downstream of the tank. In this way, if you leave your manual shut-off valve open while leaving the boat unattended and a major leak develops, fuel will not flow from the tank. These valves are OK in principle, but the "controlled restriction" that they introduce, does have the potential of creating problems in some fuel systems. For example, I think they would be really troublesome in the Catalina 30 fleet, with fuel tanks so low and far from the engine.

Hopefully, these suggestions might help to identify a few latent problems that may be lurking in other fuel systems before the onset of frustrating shutdowns related to fuel supply problems.

Don

Last edited by Don Moyer; 07-12-2006 at 09:46 AM.
Reply With Quote
The Following 2 Users Say Thank You to Don Moyer For This Useful Post:
JDK (08-03-2016), TimBSmith (09-07-2020)
  #2   IP: 71.132.23.221
Old 07-05-2006, 01:55 AM
autorot8 autorot8 is offline
Senior Member
 
Join Date: Mar 2006
Location: SF Bay Area
Posts: 17
Thanks: 0
Thanked 0 Times in 0 Posts
It worked!

Don,
I read this article over and over...it made alot of sense. I took all of your suggestions and put them into play.

From you I ordered, then installed a new electric fuel pump, water filter/seperator. I installed new 5/16" fuel lines from tank to carb and a prime bulb that is easily accessed in cockpit.
The installation took about an hour, the prime bulb primed and pressurized system in a few squeezes.
The engine fired right up and runs a heck of alot better. I motored around for over an hour and it seems that the engine is almost as good as new. Temp never went over 140, oil pressure was great and she seemed to purr like she hasn't in a long, long time.

The overall first impression is that the mechanical pump was not providing sufficient supply of fuel and that it leaked air via the glass sediment bowl. The electric fuel pump seems to provide more than adaquate fuel supply. The engine runs smoother and is more responsive. Wish I had made these improvements sooner...
ALL Atomic 4 engines should have these upgrades in my opinion. It has made a huge difference to my boat and my love/hate relationship with these engines. I even considered retiring my atomic 4 and going to a long shaft outboard until I could afford a repower to diesel... Well now, I seem to be satisfied with the results of these products.
I had never heard of fuel related engine shutdown, now I wont have to experience it anymore either.
Attached Images
 
Reply With Quote
  #3   IP: 207.59.162.172
Old 07-05-2006, 01:45 PM
laserandy laserandy is offline
Member
 
Join Date: Jun 2006
Posts: 4
Thanks: 0
Thanked 0 Times in 0 Posts
Any modifications to use electronic pump?

Did you have to remove the mechanical pump, or did you just put the electronic pump inline and have at it?

Andrew
Reply With Quote
  #4   IP: 64.50.17.163
Old 07-05-2006, 02:02 PM
autorot8 autorot8 is offline
Senior Member
 
Join Date: Mar 2006
Location: SF Bay Area
Posts: 17
Thanks: 0
Thanked 0 Times in 0 Posts
mechanical pump

I basically replaced the entire fuel system and effectively retired the old mechanical pump.
The old pump is still attached to the engine block. I did remove ALL the fuel lines from old pump and also removed the sediment bowl. The old pump is now just an eyesore.

I placed a towel on top of pump, so that when engine first fired up with new parts, the residual fuel (left in pump) would not be sprayed all over the engine. Good thing to, the towel was saturated!
Reply With Quote
  #5   IP: 38.118.52.41
Old 07-05-2006, 02:19 PM
Administrator's Avatar
Administrator Administrator is offline
MMI Webmaster
 
Join Date: Oct 2004
Location: Chestertown, MD (Langford Creek)
Posts: 2,198
Thanks: 1,335
Thanked 349 Times in 176 Posts
If you decide you want to remove the old pump, here's the cover plate you'll need.

Bill
Reply With Quote
  #6   IP: 169.128.252.100
Old 07-11-2006, 10:14 AM
cc29_buckeye cc29_buckeye is offline
Frequent Contributor
 
Join Date: Jul 2006
Posts: 8
Thanks: 0
Thanked 0 Times in 0 Posts
Fuel Frustrations...

As we were returning from a week long cruise, my engine (1977) started showing signs of fuel starvation (and of course a loss of power). Although it never died, it ran extremely rough only while under load (e.g. only in gear). I did have to be towed in the last hour of the trip.

I replace the in-line fuel filter prior to the trip and motored for more than 15-20 hours prior to this problem. I did notice (it is a clear filter) it runs seemly dry during most operation. I did not "bleed" the system after replacing the filter because I was told with gas engines, the fuel pump will pull what it needs (I have an electronic fuel pump).

I have been reading a bunch and am thinking it may be a blockage but before I pull the pick up tube and possibly the tank to inspect and clean it, I would like some suggestions...

I intend on replacing the fuel lines (incase I have an air leak) and adding a priming bulb to prime the system and see if this corrects the problem. Any other thoughts???

Thanks!
Reply With Quote
  #7   IP: 38.118.52.41
Old 07-12-2006, 06:56 AM
Don Moyer's Avatar
Don Moyer Don Moyer is offline
 
Join Date: Oct 2004
Posts: 2,807
Thanks: 0
Thanked 142 Times in 91 Posts
I believe you're on the right track. One additional consideration is that electric fuel pumps do not create suction head nearly as efficiently as mechanical pumps, so they are not quite as forgiving of small amounts of air in the system.

Don
Reply With Quote
  #8   IP: 75.109.251.205
Old 07-23-2007, 01:00 PM
J. Fred Bear J. Fred Bear is offline
Senior Member
 
Join Date: Jul 2007
Posts: 11
Thanks: 0
Thanked 2 Times in 2 Posts
Primer bulb location?

I want to install a primer bulb. Where, exactly , does it go: between fuel
tank and fuel filter?; or fuel filter and engine; or some other place?.

Can you connect it with regular small hose clamps?

Also, I'm ordering a Racor. You suggest an inline filter as well. Where does
this second filter go?

Thanks.....



Fred Bear
Reply With Quote
  #9   IP: 38.118.52.41
Old 07-23-2007, 07:47 PM
Don Moyer's Avatar
Don Moyer Don Moyer is offline
 
Join Date: Oct 2004
Posts: 2,807
Thanks: 0
Thanked 142 Times in 91 Posts
Fred,

The priming bulb mounts between the fuel tank and the RACOR filter.

The inline (secondary or polishing) installs between the fuel pump and carburetor.

Don
Reply With Quote
  #10   IP: 75.109.251.205
Old 07-25-2007, 02:17 AM
J. Fred Bear J. Fred Bear is offline
Senior Member
 
Join Date: Jul 2007
Posts: 11
Thanks: 0
Thanked 2 Times in 2 Posts
Primer bulb ok!

Don

In installed a primer bulb between the old gas filter (Fram.....made in Turkey...the country....not the thanksgiving bird.)
and the gas shutoff cock.

Works fine......filled the entire gas line to the carb very fast......

Thanks for the suggestion.

Engine still would start...run for a few seconds...then quit.....
So I removed carb....left it with a small engine mechanic....he will check for
obstructions in the jets......I
I found small bits of soft black material in the gas....mechanic says its residue from old rubber gas hoses and that CAN clog the jets.
So I'll replace the hoses too.

So the situation goes on..........sooner or later I will get this atomic beast to
run....

Fred Bear
Reply With Quote
The Following User Says Thank You to J. Fred Bear For This Useful Post:
TimBSmith (09-07-2020)
  #11   IP: 24.150.88.62
Old 08-06-2007, 11:38 AM
Angus Angus is offline
Member
 
Join Date: Oct 2006
Posts: 1
Thanks: 0
Thanked 1 Time in 1 Post
For quite some time I have experienced an unexplained engine shutdown. Sometimes even after running a hour and sometimes after only less than a minute after startup. I have gone through the recommended procedures to detect the fault, finally arriving at the conclusion fuel starvation is my problem. I have dismantled and thoroughly cleaned the Zenith 61 carburetter, and having installed a kit only two years previously did not, at this time, think about replacing any parts of the carburetter after checking the integrity of the float, its setting in relationship to the casting etc. Finally I deduced the float valve may not be allowing fuel to flow into the chamber. On the next occasion the engine stopped (alongside the dock) I carefully removed the carburetter holding it in a level position I removed the four screws and lowered the bottom casting to expose the float and noted the pin valve had not dropped down as it should have when the floats dropped thus shutting off the fuel supply to the bowl. I disassembled the float and the valve seat to check for some obstruction and there was none. I used fine steel wool to make sure there was not gum on the triangular sides of the valve and the valve seat. After re-assembly I noted that the pin still remained seated after being pushed up against the seat (see attachment). I carried out this procedure perhaps three times and finally ordered a new valve and seat from Moyers. This I installed and within three weeks I experienced the same symptoms. When I talked to the representative at Moyers, I asked about ethanol deterioration of the plastic/rubber 'tit' on the end of the triangular valve, due to ethanol additives. There had been no reports. I think there might be a correlation here. A fellow Atomic4 owner noting my frustration, suggested I use his old spare Carburetter. After fitting it the engine ran for an hour without hesitation! The control hookups were different and would need alteration so I decided to dismantle the replacement carburetter and only use the valve and seat. It was at this point I noted a difference, taking the valve out of its seating I noted the point was steel, not rubber/plastic. I fitted the assembly to my engine and it has run without faltering ever since. Now I am hoping I can obtain an all steel valve for my carburetter.

Cheers, Angus
Attached Images
 
Reply With Quote
The Following User Says Thank You to Angus For This Useful Post:
TimBSmith (09-07-2020)
  #12   IP: 216.58.96.134
Old 08-26-2007, 10:48 AM
lhbradley lhbradley is offline
Senior Member
 
Join Date: Oct 2004
Location: Ottawa, Canada
Posts: 37
Thanks: 0
Thanked 1 Time in 1 Post
Priming bulb caution

Don recommends an outboard-style priming bulb. I put one in my fuel system about 4 years ago, because the priming lever on the mechanical fuel pump was partially broken and didn't work too well. The bulb worked well.

Last year I changed to an electric fuel pump, and left the primer bulb in place. On a few occasions during the year, the engine would just quit. Squeezing the priming bulb allowed me to start the engine and all would be well for several weeks. It was suggested to me that there might be an air leak, but I could not find anything.

This year, one day the engine would not start. At all. Squeezing bulb didn't help - in fact, bulb was very had to squeeze. I removed the bulb from the fuel line, and the problem disappeared. I took the bulb apart, and found that one of the balls in the valves was sticking, not allowing fuel through.

Moral of the story:

If you have a fuel starvation problem, bypass the priming bulb as one of your tests.

And perhaps taking the bulb out once a season and cleaning the valves might be a good idea. They use spring-type clips on the bulb, but after taking it apart, you could use hose clamps, since the clips probably won't go back on properly.

Or just replace the bulb every year or two.
__________________
Larry Bradley
C&C Corvette 31 "Lady Di"
Clark's Marina
Gananoque, ON, Canada
in the beautiful Thousand Island
of the St. Lawrence River
Reply With Quote
  #13   IP: 72.69.143.216
Old 08-26-2007, 03:55 PM
baileyem baileyem is offline
Senior Member
 
Join Date: Jun 2006
Location: Tomahawk, WI
Posts: 175
Thanks: 0
Thanked 0 Times in 0 Posts
a different twist

My A4, early model, with mechanical fuel pump & std ignition system, has just developed what seems to be a fuel related problem similar to those described above, but with a different twist....the engine starts and runs well, When I push it to 1700 rpm it runs well for 3 to 15 minutes at that speed and then begins to rapidly lose power and rpm to about 800-1000. ( it sounds like it is starving for fuel, but doesn't cut out completely ) If I don't mess with the throttle setting the rpm will slowly crawl back up to 1200 where it will run very nicely for an unpredictable amount of time before running through the cycle again. However, if when the power first drops, I cut back the throttle to 800 rpm and then advance it to 1500 rpm, the engine will run at that setting very happily until I choose to change the throttle setting. For some reason the engine does not like to run at 1700 nor can I get it to reach anything above that.

I suspect that my float level is not set high enough, or my fuel pump will not deliver the amount of fuel required at the higher throttle settings.

I would appreciate any comments on my problem before I tear into it.

Thanks, Mike
Reply With Quote
  #14   IP: 70.88.210.178
Old 08-27-2007, 05:51 AM
jhwelch's Avatar
jhwelch jhwelch is offline
Senior Member
 
Join Date: Dec 2005
Posts: 477
Thanks: 0
Thanked 4 Times in 4 Posts
I bet your carb. float is sticking and not opening fully. I've temporarily
fixed this by tapping on the carb. Sometimes it lets the float drop free.
Once I get to a stopping point I take the carb. off and clean it out.

-jonathan
Reply With Quote
The Following User Says Thank You to jhwelch For This Useful Post:
TimBSmith (09-07-2020)
  #15   IP: 38.118.52.41
Old 08-27-2007, 08:23 AM
Don Moyer's Avatar
Don Moyer Don Moyer is offline
 
Join Date: Oct 2004
Posts: 2,807
Thanks: 0
Thanked 142 Times in 91 Posts
Mike,

I agree with Jonathan and would add that your symptoms are also consistent with low fuel pressure. I'm attaching a troubleshooting guide to check your fuel pump.

Don
Attached Images
File Type: pdf Mechanical fuel pump check.pdf (10.4 KB, 2134 views)
Reply With Quote
The Following User Says Thank You to Don Moyer For This Useful Post:
TimBSmith (09-07-2020)
  #16   IP: 72.69.143.216
Old 08-27-2007, 03:23 PM
baileyem baileyem is offline
Senior Member
 
Join Date: Jun 2006
Location: Tomahawk, WI
Posts: 175
Thanks: 0
Thanked 0 Times in 0 Posts
Thanks

Thanks Jonathan and Don for the quick responses.

Mike
Reply With Quote
  #17   IP: 72.69.143.216
Old 09-04-2007, 02:31 PM
baileyem baileyem is offline
Senior Member
 
Join Date: Jun 2006
Location: Tomahawk, WI
Posts: 175
Thanks: 0
Thanked 0 Times in 0 Posts
Smile follow-up on problem

Just a quick follow-up on my fuel problem.....Jonathon and Don were right, I ran Don's suggested test on my fuel pump and it seems to be OK. There was a lot of crud in the carburetor that I flushed out by working the mechanical fuel pumps priming arm after I had removed the main carb drain plug. So the problem was definitely dirt in the fuel that may have been giving me carb float problems as well as possibly dirty jet problems.
I did clean and change my filters before taking her out for an extended run. I am happy to say that the engine never hesitated, ran well under load, and produced 1800 RPM without problems.

The problem is that now I have to haul for the season next weekend.
Reply With Quote
  #18   IP: 207.203.67.250
Old 09-14-2007, 11:46 AM
rpn59 rpn59 is offline
Senior Member
 
Join Date: Jul 2007
Location: C.C., FL
Posts: 11
Thanks: 0
Thanked 2 Times in 2 Posts
Lightbulb Fuel starvation

Hi Don,

I read a bunch of articles on the the forum where people have considered fuel starvation as a possible problem for their ill running engines. A good and very simple technique is to spray a little starter fluid into the carb and see what happens, if the revs pick up or the engine continues to run then you know the engine wants more fuel than your fuel system is delivering and hense you need to look at the entire system to find the fault. If not, start looking at other systems, no?

Ray
__________________
Ray N.
Reply With Quote
The Following User Says Thank You to rpn59 For This Useful Post:
TimBSmith (09-07-2020)
  #19   IP: 159.18.221.197
Old 09-14-2007, 05:14 PM
Bob.Griffin Bob.Griffin is offline
Senior Member
 
Join Date: Jun 2007
Posts: 46
Thanks: 0
Thanked 4 Times in 4 Posts
This thread has generated much interest, and here's my convoluted addition, which to me is a bit of a puzzler. I have a fairly new s/s fuel tank installed by the PO but it has no opening for the fuel guage sending unit, just a small 5/8 inch opening with a bolt that the PO used with a dipstick to check fuel levels. Being a perfectionist, I wanted to have the fuel guage work properly. I wasn't prepared to remove the tank (meant dismantling half the rear end of my boat!) and have a new port cut into it, so I decided to install a small secondary tank with a syphon connection and containing a new sending unit. The syphon is a copper tube going to the bottom of the primary tank and a clear poly gas line to the secondary tank which is also vented (I wanted to use clear poly initially to check it all works). It all works fine but I noticed that tiny air bubbles could be seen coming from the primary tank and very slowly filling the syphon line with air over a period of 4 or 5 days, such that the syphon no longer works. I've checked for leaks and found none, so assumed this was dissolved air in the gas coming free (I'm no hydraulics expert!). I use a bulb to prime the syphon every time I use the boat. My question is: if this air is evolving in my syphon line, it must also be slowly filling the main line to the fuel filter as well and I wonder if sometimes the electric fuel pump cavitates until the air is eventually sucked through (main tank is above the engine and only about 2 to 3 feet from the carb), because sometimes the engine starts very rough when started and runs rough for about 10 minutes then runs fine. Am I way off course or is this possible?

Bob Griffin
C&C Corvette 'Saga'
Bath, Ontario.
Reply With Quote
The Following User Says Thank You to Bob.Griffin For This Useful Post:
TimBSmith (09-07-2020)
  #20   IP: 38.118.52.41
Old 09-15-2007, 06:53 AM
Don Moyer's Avatar
Don Moyer Don Moyer is offline
 
Join Date: Oct 2004
Posts: 2,807
Thanks: 0
Thanked 142 Times in 91 Posts
Bob,

You pose a very important question in my view and I hope others will contribute.

I'm not a hydraulics expert either, but we do know that the vapor pressure of gasoline is quite high which means that it doesn't take much of a pressure reduction from normal atmospheric pressure before evolved gas will start to come out of solution and create bubbles. When the reduced pressure equilibrates, I believe the evolved gas goes back into solution, but I'm not sure if it passes back and forth from solution at the same pressure; i.e., it may take positive pressure above normal atmospheric before the evolved gas will go back into solution.

I believe it is also true that the vapor pressure of gasoline becomes higher as temperature rises, which means that if you do have any restrictions in the fuel supply line from the tank, the tendency for gas to evolve out of solution would be worse in the heat of summer. This is probably what oldtimers used to call shutdowns from "vapor locks".

Don
Reply With Quote
The Following User Says Thank You to Don Moyer For This Useful Post:
TimBSmith (09-07-2020)
  #21   IP: 72.69.143.216
Old 09-15-2007, 07:55 PM
baileyem baileyem is offline
Senior Member
 
Join Date: Jun 2006
Location: Tomahawk, WI
Posts: 175
Thanks: 0
Thanked 0 Times in 0 Posts
vapor lock

Don
I don't think of myself as an 'old timer', but yes we used to experience vapor lock in the 'old days' (hey, I'm only 67). I drove a lot of Ford flatheads that would have problems in hot weather if the fuel lines and fuel pump got to hot. The cure was to either cool the fuel lines and pump with damp rags and cold water or to crack a fitting on the high end of the fuel line and release the air bubble. I never heard an explanation of what caused the problem. I just learned how to recognise it and how to deal with it. I think that we figured the gas got hot enough to boil, and that the boiling caused the bubble......from your explanation, I guess that is a reasonably close explanation.
I can see where an A4 stuffed into a hot, poorly ventilated engine compartment could easily develop 'vapor lock'.

Mike
Reply With Quote
  #22   IP: 159.18.221.197
Old 09-17-2007, 04:40 PM
Bob.Griffin Bob.Griffin is offline
Senior Member
 
Join Date: Jun 2007
Posts: 46
Thanks: 0
Thanked 4 Times in 4 Posts
Don/Baileyem:

Very interesting, this also explains why plastic gas cans tend to expand in hot weather. Can someone take this a step further and expalin what are the typical symptoms of a 'vapor lock'? Can one get a partial 'vapor lock'?

Bob
Reply With Quote
  #23   IP: 207.245.69.50
Old 09-20-2007, 10:19 AM
Phil Phil is offline
Senior Member
 
Join Date: Oct 2004
Location: Wilmington DE
Posts: 41
Thanks: 0
Thanked 1 Time in 1 Post
http://en.wikipedia.org/wiki/Vapour_lock
Reply With Quote
The Following User Says Thank You to Phil For This Useful Post:
TimBSmith (09-07-2020)
  #24   IP: 38.118.52.41
Old 09-20-2007, 11:29 AM
Don Moyer's Avatar
Don Moyer Don Moyer is offline
 
Join Date: Oct 2004
Posts: 2,807
Thanks: 0
Thanked 142 Times in 91 Posts
Good article, Phil!

Don
Reply With Quote
  #25   IP: 74.123.191.26
Old 09-24-2007, 03:24 PM
Bob.Griffin Bob.Griffin is offline
Senior Member
 
Join Date: Jun 2007
Posts: 46
Thanks: 0
Thanked 4 Times in 4 Posts
Thanks Phil, that certainly helps. I imagine the problem with boats is when they are left for periods of time (during the week when we have to work) and in hot weather, the vapour lock slowly forms over time. I'm temped to test this theory by replacing the gas line from tank to fuel pump with a clear plastic line and see what happens. My gas line comes out of the top of the fuel tank which doesn't help, if it came out of the bottom of the tank and runs down hill to the pump, I'd never get a vapour lock. What happens to the vapour lock when it hits the fuel filter?

Don, rather than replumbing my fuel tank (highly unlikely), will a prime bulb fix the problem? I do get stalling and poor running for about 10 minutes after I start from cold, and the choke helps a lot which does suggest fuel starvation which I think is caused by a vapour lock.

Bob c/o Saga, Ontario
Reply With Quote
The Following User Says Thank You to Bob.Griffin For This Useful Post:
TimBSmith (09-11-2020)
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Checklist for a troublefree spring startup Don Moyer General Interest 11 05-03-2017 01:05 PM
Atomic 4 Fuel Consumption Don Moyer Fuel System 47 06-05-2012 08:35 AM
Removing the engine from your boat Don Moyer General Interest 13 06-27-2008 11:06 AM
Spark plug gap Unregistered Electrical 2 04-07-2006 11:31 AM
Fuel starved engine photoflash Fuel System 1 09-14-2005 04:54 PM


All times are GMT -4. The time now is 11:00 AM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2020, vBulletin Solutions, Inc.


Universal® is a registered trademark of Westerbeke Corporation

Copyright © 2004-2020 Moyer Marine Inc.

All Rights Reserved