Alternatives to Facet

[ndutton]

I will take Neil's advice and run without the flame arrestor

Not so much advice as trying to eliminate possibilities one at a time. The throttle linkage idea is another possibility that needs elimination, maybe on the same test run.

[HalcyonS]

eliminate possibilities one at a time.

right That's my plan.

[HalcyonS]

question abourt pressure gauges

I can suggest this gauge. I use it on my boat and like it.

http://www.ebay.com/itm/Pressure-Transducer-Gauge-5-psi-2-1-16-52mm-analog-voltage-input-LED-light-/262058478258

http://www.ebay.com/itm/Pressure-transducer-sender-5-psi-stainless-steel-for-oil-fuel-air-water-/251520321321

I don't think I want to go to the trouble of fitting a dash-mount gauge since I plan to rebuild my panel. A gauge in the line will be fine for troubleshooting.

1-5psi is rare, 0-10 more common, but 0-15 seems to be standard, and probably has enough resolution and plenty of headroom.

There are some very cheap gauges on fleabay, claiming fuel/air/water use, but they're not liquid filled. For instance -

http://www.ebay.com/itm/50mm-0-15-PSI-0-1-Bar-1-4-BSPT-Low-Pressure-Gauge-for-Fuel-Air-Oil-Gas-Water-/222308861891?hash=item33c2a407c3:g:NcwAAOSw4GVYIR3t

What is the reason for a liquid filled gauge?

thx!

[joe_db]

http://www.ebay.com/itm/New-Hydraulic-Liquid-Filled-Pressure-Gauge-0-15-PSI-/262704067579?hash=item3d2a61f3fb:g:~AsAAOSwQoFWPA2R

This is the one (or similar) that I had before I got the electrical gauge. The glycerin keeps the needle from bouncing around as the pump works. It is very effective at smoothing the needle out.
WARNING - the gauge has to be upright and you need to make a hole in the rubber vent plug or the readings will be way off. Don't ask

[HalcyonS]

http://www.ebay.com/itm/New-Hydrauli...sAAOSwQoFWPA2R

WARNING - the gauge has to be upright and you need to make a hole in the rubber vent plug or the readings will be way off. Don't ask

I'd bookmarked that gauge.

oh yeah, I recall that now in a thread back there...thanks for the reminder

[HalcyonS]

all fixed

Not sure why, but here's what I did.

Remounted airpax pump with custom bracket. (note copper fuel inlet line under gauge - its a but of a maze in that dept now

Note angle. The say to mount it 15 to 45 deg, to float out air. I guess on automotive situations it tends to be horizontal.

Getting the screws in was a pita especially since I had to reposition it twice. Escaped with only one badly skinned knuckle Engine bay is real tight - what I'd do far a few more inches each side!

Plumbed in a 15 psi gauge I had in stock - cheapie, bounces around at some revs, but does the job.
Plumbed in polishing filter - barely visible, I know its not coast-guard legal, I'll change it out now I have a gauge.

It ran like a charm, revving up to 3500. Pump is whisper quite and holding 3psi.

Polishisng filter still has substantial air, only bottom 1/5 ot\r so is gas. Not sure how it can work like that. I put it low to work the air out, but it doesn't move.

Question - how does air bleed out of system? Does the float bowl needle bleed it out - under normal conditions? or do I need to add a bleed line above the fuel pump (I have one arm of the cross plugged

I then ran seafoam through the spigot on the cannister filter - bottom left. Adding the spigot was a smart move for diagnostics and treatment. I can run fuel in to test fuel line/filter problems. I ran the seafoam in there and could meter it with the spigot. Then changed oil.

all good - till next time

[joe_db]

What is your address? I might have a spare glycerin filled gauge I can send you.

[HalcyonS]

fuel line blues

it was all working last week. Yesterday, brought some friends over to sail, started engine, fired up, closed choke, died instantly. Tried again, fired up and died. Then nothing.

Anyone seen the video of John Cleese beating up his car? I felt like that.

https://www.youtube.com/watch?v=78b67l_yxUc

Sundry tests revealed the pump is pumping fuel nicely, so (yes, Neil) it looks like one or more carb jets is blocked, It may have been me fooling with hoses, hard to sop a tiny speck of rubber being knocked off by the hosebarbs I guess. Or it's accumulated ethanol crud. It's been on and off all fall now, guess I have to bite the bullet and pull the carb off - again. Dunno, this annual carb strip down caper is getting old...

[HalcyonS]

airlocks in fuel line

as noted, I have a plastic polishing filter currently. I like it as I can see if fuel is flowing. As you can see from previous pics, the filter is below the pump, the very lowest point in the fuel line. Pump pumps gas, but the filter is empty. I'm not sure how fuel is flowing nor why the huge air pocket won't go away. The pump is mounted more or less vertical above the filter, yet the air doesn't rise up !?!
I asked this before but afaik, didn't get an answer - does the carb needle valve function as an air bleed?
Anyone got experience with similar issues?
thanks

[JOHN COOKSON]

Did you visually verify that the choke was opening and closing like you expected it was?
Are the spark plugs wet with fuel after a period of no start cranking?

If you are feeding the filter from the top it will not fill with fuel. There will appear to be sort of a constant puddle in the filter. The reason for this the filter has a much greater diameter than the fuel line.

TRUE GRIT

Edit: I'm not 100% convinced the problem is on the fuel side. After the next no start\shutdown leave the key (or switch) in the on position and take a voltage at coil+ or use a short length of wire and spark test coil +.

[ndutton]

Many of those little filters have a check valve in them so flow is one direction only. If installed in the proper direction the air would not burp out toward the pump. If it's installed backwards . . . . no fill and no flow.

Now that we know the pump is working there are very few possibilities left between the pump and the carburetor bowl. Be methodical, don't overlook anything or assume it's correct. Really all we are looking at now is the filter and carburetor. Depending on what is found there we may be back at the tank, the source of all that is evil.

You are not alone in resisting carburetor removal and rebuild, many forum members feel the same but a few of us make it a regular routine just like changing spark plugs or engine oil. I just rebuilt mine a month ago and I had no running problems at all. Here's the point: I don't expect to either.

[67c&ccorv]

While my boat doesn't have an Atomic 4 in it I found a pretty good electric fuel pump (rated for 18,000+ hrs) that uses the same fuel pressure as needed in the A4.

https://walbrofuelpumps.com/marine-industrial-fuel-pump

I am in the process of replacing what the previous owner had installed in the vessel (pic. #1 ) with something a little more appropriate (pic #2 showing fuel control with 12v solenoid valve/Walbro pump/proper fuel filter for inboard gas engines/3 way Swagelock valve that allows bypassing solenoid valve and fuel filter in the event of malfunction of either pic.#3&4) - oh, did I mention everything on this ship is X2?

[HalcyonS]

While my boat doesn't have an Atomic 4 in it I found a pretty good electric fuel pump (rated for 18,000+ hrs) that uses the same fuel pressure as needed in the A4.

https://walbrofuelpumps.com/marine-industrial-fuel-pump

I am in the process of replacing what the previous owner had installed in the vessel (pic. #1 ) with something a little more appropriate (pic #2 showing fuel control with 12v solenoid valve/Walbro pump/proper fuel filter for inboard gas engines/3 way Swagelock valve that allows bypassing solenoid valve and fuel filter in the event of malfunction of either pic.#3&4) - oh, did I mention everything on this ship is X2?

now that (new arrrangement) is classy!
thanks for the Walbro ref.
Which pump is the 2-4 gph spec recommended for A4 - I don't see apressure spec on their website - at least the page you sent.

[HalcyonS]

John and Neil
thanks for your comments. To clarify, the polishing filter is currently upstream of the pump, but physically at the lowest point in the fuel line, as you'll see in the pic a post or two back.

@ neil :
Many of those little filters have a check valve in them so flow is one direction only. If installed in the proper direction the air would not burp out toward the pump. If it's installed backwards . . . . no fill and no flow.

filter is right way round, fuel is flowing well. I can confirm this indubitably. How? I took the pressure valve off, added a spigot and hose, and pumped a pint or two into a jerrycan. Yup, plenty of flow. But the airlock didn't change.

@ neil :
Now that we know the pump is working there are very few possibilities left between the pump and the carburetor bowl. ... Really all we are looking at now is the filter and carburetor.

not even (!) as filter is (currently) upstream of pump. Nothing but a brass nipple, some fittings and 4" of hose between pump and carb.

but a few of us make it a regular routine just like changing spark plugs or engine oil.

@ neil :
yup, next step, asap, clean carb, relocate filter between pump and carb, and try again

@ neil :
we may be back at the tank, the source of all that is evil.

I know I know, everyone says tank. But look - 3 filters in line? The WC bronze strainer pulls out plenty of pale green monel dust - and almost no water - I guess its dissolved by the ethanol. Which can't be a bad thing! Water vapor cools the engine while adding compression. On the other hand, water may be coming out of solution in the pressure/temerature variations in the carb - I'm not clever enough to figure that out. Maybe Dave knows?

But in terms of things filter can stop (ie not dissolved things), the Sierra pulls out what the WC doesn't, and the polishing filter gets the rest.

I could put this to the test - dump a bucket of mud in the fuel tank...but I think I won't

@ John:
Did you visually verify that the choke was opening and closing like you expected it was? Are the spark plugs wet with fuel after a period of no start cranking?

choke is fine. wet plugs? I'll check next time after I clean the carb and/if it doesn't burst into life.

@ john:
After the next no start\shutdown leave the key (or switch) in the on position and take a voltage at coil+ or use a short length of wire and spark test coil +.

I'm pretty confident of the coil too, but... sh*t happens. will check

thanks guys
Simon

[ndutton]

I misunderstood the position of your polishing filter, thought it was in the conventional location.