Stalls unless choked

[vindauga]

My A4 on my 1976 Ericson 27 has always run like a top but suddenly it I'm having a problem. It starts and idles fine but when I speed it up it wants to stall. Pulling the choke out about half way keeps it running but obviously there is a problem. There is no fuel filter (but after reading a bunch of these posts I'm going to put one in). I'm assuming that I have a fuel problem but I'm not sure where to start. Help! Thanks!

[jhwelch]

It sounds like you may have a bit of grit in the main jet. When this has happened to me I've taken my carb. off and used compressed air to blow out all the jets and tubes. Other people will recommend using carb. cleaner. You may see this symptom if you have a small air leak, too, but from your lack of fuel filter I'd first suspect a tiny bit of grit.

-Jonathan

[H3LlIoN]

Like he said, check for blockage. The choke restricts air flow to the engine, which would increase the AFR. If it was running fine, and you haven't messed with any screws, then something is starving the carb for fuel and causing it to run lean.

[sastanley]

vindauga, welcome to the forum.


I agree that that main jet is likely clogged up..

You can try to remove the main passage plug (it has a fiber washer that is fragile, be careful) and flush some fuel into a suitable jar or container and see if that helps...otherwise, the proper fix is to remove the carb and clean it using methods mentioned above.

[CalebD]

Might also want to check your fuel supply as the E10 fuel seems to create crap that is just not good for continuous running.
The pic below is from the last 2 gals in my tank that I hand pumped out.
Oh, and the amber colored liquid is mostly gas while the darker colored liquid is not.

[jpian0923]

CalebD,

Did you ever figure out what the black stuff was? I have a bad memory. And I don't listen well (I've been told).

[CalebD]

Crud

Jim,
That 'black stuff' floating underneath the amber looking fuel is most likely from E10 phase separating in my tank over the 7-8 years we've had the boat. Once the ethanol separates from the gasoline it traps H2O in the fuel. Water being heavier then gas floats underneath what passes for fuel.
Otherwise the 'black stuff' is affectionately known as 'crud' does nothing good for your filters, carb or engine. It can cause difficult starting, stalling, a hunting tachometer and is just generally bad.

[vindauga]

Thanks everyone for the replies. I'm embarassed to say that the problem was in the fuel bowl upstream of the pump. The screen was completely plugged and the bowl was about 1/3 full of crud. I never realized that this was something that I should check. I don't know why the engine ran at all. Order a new bowl, screen and gasket. Works great now. Oh by the way, another post mentioned that a small air leak would starve the engine but not show up as fuel leak. That's exactly what happened when I put the new bowl on. Engine wanted to stall but as soon as I gave the bowl nut one more turn it ran fine. Apparently enough of a leak to let air in but not let the fuel out.

[domenic]

Ethanol eats the fiberglass.Open your tank and see if there is stuff that looks like dark sand...that is fibergalss. ethanol ate a hole in my tank this past year. I had to replace my complete fuel system. When you see ethanol, say "Boooo."

[sastanley]

vindauga, thanks for the follow up. It always helps other A4 owners down the road when they search the archives for similar problems.

There are pics floating around here on the forum of the contents of my fuel pump bowl in late 2008 that look exactly like Caleb's 'fuel mixture' in his gallon jugs...it sounds like you found something similar.

I think I said the same thing: "I don't know how this poor engine ran at all.."