Engine won't start

[David Pugh]

Hi, my name is Dave and for some reason my thread did not get posted. My engine won't start, it fires enough to disengage the starter and that's it. I have worked on the engine extensively, new fuel tank, rebuilt fuel pump, new carberator, it ran good with one exception, it won't idle in neutral. Now this year I have this new issue, compression @ 50 on first spin the up to 75 after 3 spins. Raw fuel in the manifold but plugs are dry with no smell of gas in cylinders. Sounds like I have an issue with the carb. but it is new and I hate to take it apart. Can anyone advise?

Help, Dave.

[BunnyPlanet169]

Hi Dave - and welcome to the forum!

How about a bit more information.... Previous history with the engine and maintenance (new to you?, first start this year?, always started before?, etc), fuel system (mechanical or electric fuel pump?, OPSS? fuel pressure gauge?, filters and status?, hoses replaced?, etc).

First blush, sounds like a fuel problem, but we'll do better to diagnose with more information.

Raw fuel in the manifold but plugs are dry with no smell of gas in cylinders.

Which manifold? Intake/exhaust or carb body after flame arrestor?

(see you edited - thanks!)

[JOHN COOKSON]

Originally Posted by David Pugh

. Now this year I have this new issue, compression @ 50 on first spin the up to 75 after 3 spins. Raw fuel in the manifold but plugs are dry with no smell of gas in cylinders.
Help, Dave.

Is the marginal compression in all cylinders or just one? Could be some stuck rings going on here???????? Did you try a "wet" and "dry" compression test?

TRUE GRIT

[Marian Claire]

Another welcome:
Good advice from others. The more info we have the better. Including a time line of events. Was the fuel pump worked on after the carb was installed? Have you ever adjusted the carb? Is there a filter between the pump and carb?

Dan S/V Marian Claire

Just across the river at Matthews Point. If you are still having issues I would be happy to stop by on my next trip down there.

[David Pugh]

First off; Thanks to all for the rapid response!
I Purchased a Pearson Vanguard last June, the boat was located in Fort Pierce FL. I spent the entire month of June down there getting the motor running.

First I rebuilt the exaust with a stainless loop 1 foot up from the manifold and then the water entry on the down side, insulated and used the proper hoses and equipment from there. That works fine and I did have expert advice from people like Don Moyer and other locals from Oriental.

Next I had issues with fuel getting to the carb. I installed a new fuel tank, 1/4 in. hose to a valve on the bulkhead into a filter/water separator then 1/4in. hose to a secondary filter ahead of the fuel pump. I rebuilt the fuel pump and installed a pressure guage between the fuel pump and the carb. By hand I could achieve 4-6 psi. Still had a fuel issue so on a Sunday I went down to the local hardware store and bought a 2' piece of 1/2" rod and some sand paper. That't right I made a new push rod for the fuel pump and that solved the problem completely.

I left Fort Pierce and headed for NC. This is my first time on the ocean with a boat this size. I decided to take the ICW and stay off open water, this meant motor all the way for 800 miles. The biggest problem I had was the engine will not idle in neutral and it goes too fast in foreward so I had problems with docking. On the way I spoke with Don Moyer often, I had a new carb. sent in the mail with hopes the idle issue would be fixed, not so but it did run better.

This is what I learned on my trip home; the engine burns about 1/2 cup of oil in 12 hard hours. I thought not bad for a 50 year old engine so this leads me to believe the lower end is in decent shape. Under heavy load, smoke would enter the cabin from the breather pipe, but only under heavy load.

The only problem I had at that time was the idle.I adjust the idle jet on my new carb, Don says it controls the air not the fuel so closing it reduces air intake. I have it set at 1 full turn now.

I arrived in Oriental August 5th. docked Dragonfly and did not try to start the engine until last week. The boat did not have heat but it wsa closed up all winter with no water problems.

When I tried to start it the bendix kept releasing the starter over and over. So I removed the carb and in my shop I blew it out but did not disassemble it. That did nothing.


Next I went to work on the ignition. Now I know the timing is most likely good enough to run the motor but I took the distributor out anyway,marking it's position first, cleaned it, points are in good shape, I had no new condensor. Reinstalled the distributor and timed it with a ohm meter so the points open @ TDC. It has a good spark, Still the same, won't start.

I checked compression again and it's lower now then it was last summer. It was about 90 after 3 spins and now it's @ 75. On the first compresson stroke it 's 50 on all four cylinders. Then I srayed oil in the cylinders and waited 2 days. No change on compresson.

Then I sprayed either into the fire arreastor and the engine started right up and ran for about 3 or 4 seconds.

I take out the plugs, they are new and look good but dry as a bone and no smell of gas but gas is pooring out of the intake of the carb.

This is what I think I need to do but not sure, I may have what I call a mindset where I get my mind set on something and forget the obvious. I can start by taking the carb apart and blow out all ports. Then install another filter between the fuel pump and the carb. See if it will start. This bothers me becsuse it's a brand new carb.

If I can get the motor running and use it this Summer, take it out this winter and lap the valves.

Thanks again for your help, Dragonfly Dave.

[Marian Claire]

"The biggest problem I had was the engine will not idle in neutral and it goes too fast in foreward so I had problems with docking."
What RPM are we talking about? So you are going along in gear at "idle" and when you shift to neutral it dies?

Dan S/V Marian Claire

[David Pugh]

This was last year when it was running on the ICW. When the engine is in forward it runs good, low idle rpm @ about 750 rpm & 3-4 mph in still waters light winds. High rpm about 1200? 5-7 mph? engine will labor and smoke from breather tube. When I back off on the throttle and shift to neutral the engine will race @ 1000 or 1200 out of control. Back off and the engine dies. When docking I had to play with the shifter constantly because I was afraid of a stall.

Dave

[BunnyPlanet169]

Then I sprayed either into the fire arreastor and the engine started right up and ran for about 3 or 4 seconds.

I take out the plugs, they are new and look good but dry as a bone and no smell of gas but gas is pooring out of the intake of the carb.

Your first-order problem is right here. It runs on ether ( = timing, spark, compression nominally ok), but gas is pooling and not atomizing. Time to disassemble and clean the carb. Given it's nearly new, carb cleaner and compressed air will go a long way. Wear goggles! The jets and little holes can shoot in unexpected directions. DAMHIKT.

[JOHN COOKSON]

Between not being able to adjust the idle and gas pouring out of the intake your carburetor is a mess!
When you get it apart check for a hole in the float(s).
There is something seriously wrong here........

TRUE GRIT

[David Pugh]

Thanks for the conformation;

As soon as the store opens I will go buy some carb. cleaner and do my best. When I was motoring the ICW Don Moyer had me remove the plug from the input port and pump gas into a glass. I was surprised at how much crap landed in the glass. For this reason I think I will install a 3rd. filter between the fuel pump and carb.

I'll let all know what transpires, Dave

[edwardc]

Originally Posted by David Pugh

...Don Moyer had me remove the plug from the input port and pump gas into a glass. I was surprised at how much crap landed in the glass....

!!!!

The A4 is an incredibly tough and tolerant beast, but the one thing it insists on is absolutely clean fuel! If you've got visible crap in your fuel, its going to raise all kinds of hell inside the carb.

[tenders]

With all this new fuel system equipment in the last year, if you're getting crud in the carb you really need to think about where the heck it's all coming from. If your water separator has somehow turned into a giant crud factory, or if the rubber is falling out of old fuel lines, you're going to be cleaning out the carb constantly OR you'll be gumming up a small inline fuel filter.

I would suggest rigging a portable fuel tank directly up to the carb so you can get that straightened out and tuned up with clean fresh fuel, the way God intended it to run.

Once that's done I'd start pumping a meaningful amount of fuel out of your tank from just upstream of your water separator. Clean and bright? Then focus on what's going on from the water separator to the mechanical fuel pump, and any filters in between.

Once that's solved, hook it all back together again and you'll be running clean as a whistle.

[David Pugh]

Thanks for the advice. I think the crap in the system is from all the work that has been done by myself and the previous owner. Now that I have replaced almost everything and cleaned the carb once more and added a third filter ahead of the carb. I think that problem is behind me. The engine runs good now but I still can't seem to get it to run smooth @ low idle. The only adjustments I have at this point is timing and idle jet. I have the timing @ TDC or a bit advanced. The idle jet is @ 1/2 turn but the engine backfires and dies @ low idle. I don't know what to do, what causes backfire, isn't that a timing issue?

If I need to clean the carb again I will.
Can someone give advice on this matter, I think I'm close but not there yet.

[tenders]

You might just have the idle speed set too low. There's a little bolt on the carb that acts as a stop, controlling how low the throttle can go. If that bolt is set at the wrong place it might be allowing the engine to try to run at too low a speed, and it'll cough and die no matter how well-tuned or clean the carb is.

My idle speed is set at about 800, I think, which is a point that works OK whether the engine is hot or still warming up. I know I could get it lower, but the engine will stall at low idle when it's cold, and I don't want that to happen.

[JOHN COOKSON]

Originally Posted by David Pugh

The idle jet is @ 1/2 turn but the engine backfires and dies @ low idle. I don't know what to do, what causes backfire, isn't that a timing issue? .

Seat the idle mixture adjusting needle gently then back it out one and a half turns.
Try closing the choke a bit when the idle acts up. This and "playing" with the idle mixture will give you a handle on whether you are to rich or lean on the idle. My current bet is you are on the lean* side.

PartII:
Fuel system aside an engine will backfire if a spark plug fires when an intake valve(s) is open. There are two causes of this: spark occuring at the wrong time due to an ignition system problem and an intake valve stuck open when the spark occures.

TRUE GRIT

*Edit: Got it backwards. Dang it. TGIF

[JOHN COOKSON]

David
See page 79 #5 left column.

TRUE GRIT