Fuel (carb?) problems ...

[Laker]

A week or so back my A Four abruptly became choke dependent. No warning signs , just started it up one day and the engine would not run without 3/4 to full choke. After a short time on choke the engine surged , sputtered , and died. I executed a very nice "dead stick" landing ; sailed right into my slip under jib , thank you.

Yesterday I started by replacing the fuel filter. (Easy thing first.) I tried blowing air thru the old one - it seemed tight. I was fairly sure that I had the cure - but no , same behavior. I dropped the sediment bowl before starting , it was full and contained nothing suspicious. Then I dumped a pint of Sea Foam into the tank , started the engine and sprayed carb cleaner repeatedly into the throat. After about 20 minutes of running time I was able to ease off most of the choke. At the 1/2 hour mark I was able to run without choke on high idle , but the engine died if I advanced the throttle.

All in all , I made progress. I went from sputtering and dying to a 1/2 hour run with less and less choke during that time , much of that time under load. While I am not quite at full function , it seems that I barking up the right tree. I do not think that the problem is in the fuel pump (mechanical) , because I did nothing which would have improved that function. All this leads me to think that the issue is one of gummed up carburetor. Could a problem of this type occur as abruptly as was my experience?

Aside from more running time in the slip , where do I go from here?

Hoping to finish the Lake Michigan season without major repairs , Laker.

[Al Schober]

Sounds like a partial blockage of the main jet in the carburetor. If you have the adjustable main jet, you can try running it in (count the turns) and out a few times. If you have the fixed jet, you can remove the plug then run a fine wire through the jet. Catch the fuel that will come out - this will empty the carb bowl.

[roadnsky]

Hoping to finish the Lake Michigan season without major repairs

Laker-
You can remove the carb and give it a very thorough cleaning in an hour or two.
That's not major.
Aside from doing that, have you tried re-adjusting the idle mixture?

[BunnyPlanet169]

I agree that removing and cleaning a carb sounds much more scary than it really is.

For good measure, you've checked the choke cable attachment/linkage?

[Laker]

Choke cable - yes , normal. I have not reset the idle mixture ; I will give that a try.

[capnward]

Sounds like a classic case of 'gummed up carburetor.' This kind of problem can definitely occur abruptly. With an engine like ours, you have to be comfortable with carburetor removal and cleaning, and the jets if they are blocked. It is in my experience the major source of problems with the A4. Do that, and you should be good to go. Make sure the little holes in the throat (idle ports) are clear, and the idle screw is 1 turn out from the seat. I agree with Al; You may be able to fix it by turning the adjustable main jet (if you have one) in to the seat and back out 1 and 1/2 turns. Or if you have a fixed main jet, remove and clean it. If that doesn't work you need to remove and open the carb. I had symptoms similar to yours once, and discovered the idle jet had something in it. Changing the inline filter at the same time is a good move. Otherwise, do everything you can to ensure your fuel is clean. Use non-ethanol if you can.

[Laker]

I use non-ethenol exclusively.

[HOTFLASH]

Non ethanol fuel

Where to you get the non-ethanol gasoline?

[ndutton]

FYI

I use a steady diet of E10, have for 11 years without a single fuel issue, replaceable cartridge main filter, no polishing filter
BUT
we've floated a theory in the past that climate may be a factor. You folks in the snow belt may have a different situation than me.

[BunnyPlanet169]

I use a steady diet of E10, have for 11 years without a single fuel issue, replaceable cartridge main filter, no polishing filter
BUT
we've floated a theory in the past that climate may be a factor. You folks in the snow belt may have a different situation than me.

I'll bet it's the frequent use of your boat, and resulting fuel turnover. Like you say, it's us folks with more, shall we say annually sporadic use, that have issues with ethanol.

[ndutton]

You'd lose the bet. My boat sat in the slip for over a year due to the passing of both my parents in 2015 and me being the executor and Trustee for everything. Fuel tank was nearly full the entire time and still is. My boating excursion a couple of weeks ago came off without a hitch, both under power and sail.

Side note:
The energy and camaraderie of this forum saved me from going stark raving mad during the worst of times. I'm indebted to all of you.

[BunnyPlanet169]

I've been wrong before, and I'm quite sure it will happen again. I'm sorry to hear that Neil -that's just hard and painful, no doubt.

Now that we've gone full thread hijack - Laker, did you blow out the passages in your carb?

[ndutton]

Except for the side note I was trying to suggest ethanol is the go-to scapegoat for almost anything on a gasoline powered boat. We've seen in the past that professional mechanics are particularly guilty of this generalization.

My idle is erratic = ethanol
Engine is hard to start = ethanol
Engine dies = ethanol
Corn flakes stale = ethanol
Won't reach full RPM = ethanol
Big toe hurts = ethanol

And thanks for the kind words. 2015 sucked to high Heaven. My dog who was my best friend for 17 years passed in November too. I've never celebrated New Year's as much as I did when that stinking year came to a close. We're back on the water though - things are looking better, much better.

[Laker]

No thread hijack resentment here at all.

Congratulations to Neil for weathering the storm. That's what strong people do.

As to ethanol , if I were King I would abolish that.*&#?@*** stuff. But , that is a different discussion.

Carb work day is Saturday. I will post results.

Thank you , Laker

[ndutton]

Thanks Laker, such is life. Some days chicken, some days feathers.