04 2stroke 40 carb problems

[Scbowfisher]

I'm trying to set the jets and wondering the set points including the needle jet and how to set it

[boscoe99]

1 and 1/2 turns out from being lightly seated. Plus or minus 1/4 turn.

[Scbowfisher]

Ok well I've tried that and it still won't even try an run. New plugs and cleaned carbs and set jets. Still nothing. Any thoughts.

[boscoe99]

Were the carburetors completely disassembled and cleaned in an ultra sonic cleaner? And were all of the passageways verified to be open and clear?

Are you sure that this is a fuel related problem?

Could be lack of compression.

Could be lack of spark.

What happens if you spritz some gasoline or starter fluid into the carburetor inlets? Does it not fire at all?

[Scbowfisher]

Yes. If I put gas in carb it will run a few seconds then shutoff. And no it wasn't clean in ultrasonic cleaner.

[TownsendsFJR1300]

Are you putting fuel down the fuel line into the float bowl or just spraying some down the throat of the carb?

If spraying down the throat, the carb internals are probably clogged/varnished up. The jets are VERY SMALL and it doesn't take much to clog them. I would pull the jets completly out and make sure ALL ORIFICES ARE SPOTLESS.

Pulling the drain plug on the carb float bowl would let you know if fuel is even making it to the carb..

If after that it still doesn't get fuel, I'd be checking the fuel pump first, lines, tank, vent, etc.

ANY previous HISTORY, issues you can give on the engine (ie, sat for 5 years with old fuel, has run every day, no issues, fuel stabilizer used, replaced fuel lines, etc) would help alot with diagnosis.

[Scbowfisher]

Ok. I just boat the boat. It had been sitting for over a year. With muffs on it it cranked up and idle a little rough but it did run. So we go to the lake. Crank it up fine still rough idle. As I pulled away from dock it shut down. I drained gas in tank and put 6gallons of new gas as well as sea foam. I replace diaphragm in the prime start as it was torn. Fuel line. Cleaned filter and jets in all carbs 2 times but all by hand. Also new NGk plugs. And yes it is getting gas to the bowls just not into carb. Gas straight in carb it fires right up.

[Scbowfisher]

Also I pulled the fuel pump off and took it apart and the rubber diaphragm inside had some small cracks in it like dry rot.

[TownsendsFJR1300]

If there's fuel in the bowls and it only revs when you spray fuel into the throats, the carbs are still not right. Wether there's a piece of crap floating about or ? I'm assuming you repaired what ever dry rot, etc issues you found..

With the engine sitting for a year, you have a varnish, clogged carb issue.

Did you physically pull the jets out? Looking thru the carb body isn't good enough. Some of the smaller jets have tiny holes that run horizontal(not just straigh thru). Those clog very easily. Your symptoms are exactly that of clogged jets. Fuel is in the bowl, but isn't getting sucked up and vaporized for ignition (spraying fuel manually is doing that)

I've always cleaned carbs by hand, but the jets are the main issue.

Filling the float bowls with STRAIGHT Seafoam and letting it sit for at least 24 hours may get to what you likely missed, but, IME, I'd pull the carbs off again and check those jets, float needle, etc. Should you put Seafoam in the carb bowl body, drainn it BEFORE trying to re-start and prime with fuel or you'll foul the spark plugs.


Please read this thread, similar issue (carb) and repair (post #11 especially):

http://www.yamahaoutboardparts.com/f...e-th23100.html