Honda 5 hp outboard floods and quits

[IslandYacht]

While running along The carb will start spewing fuel out of a vent on the top. The engine will start running rough and, unless kept full throtle and spewing fuel, will quit. I can limp along by removing the fuel line from the tank and reconnecting when engine falters. Second new carb on engine and all the same problem ultimately. Any ideas?


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[a64pilot]

Sounds like a stuck needle valve, the job of the needle valve of course is to maintain a fuel level within the the float bowl.
Easy to take apart and clean, easier than cleaning the jets, but if I was there anyway, I'd clean the whole thing.

On edit, I'm sure you have heard to run only non ethanol fuel if at all possible, and always use sta-bil in the fuel, the green sta-nil does seem to work better than the red, although that may be just a placebo effect. But Sta-bil, does work


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[belizesailor]

+1. Highly likely a stuck float valve. Easy to fix...just clean it.

Dont know on the Honda 5, but some connect to the float, which helps to pull the valve back down if stuck. Some use a little wire clip for this connection, which can fail and make a stuck valve more likely.

[four winds]

IslandYacht, you replaced entire carb twice and problem persists? Not likely three different needle/seat combos would act up.

Or did you clean the carb twice with no improvement? If so the needle would be the likely cause. Inspect for a small groove on the tip indicating wear and relace if so. Also, how well is the fuel filtering working? A suprisingly small bit of contaminate will stick a needle and seat. And requiring repeated cleaning until the filtering is improved.

[Xthewater]

Contaminated fuel my guess. I would check for water and rust in the tank if it's metal. Rust particals can get in the float needle keeping it from seating.

[marlinmike]

Sometime with a problem like this take off the boat, hold sideways and give it a good shake. But like others have said, really need to address fuel quality, might need a pre-filter, the new reg's have jets on carbs rather small and numerous problems.

[captain mitch]

It is most likely just a sticking float.
Sta-bil is an amazing material for removing sludge and varnish from a fuel system. (I did this to a 280ZX that had sat in a barn for 25 years and cleared ALL the system, including injectors)
Check the fuel tank for any obvious signs of crud, then start with non- e fuel, load it with 9 times the recomended dose of Sta-bil, start the motor and run it for a few minutes to be sure this mix gets into the carb. Let it sit over-nite or a couple days if possible. Run it for a while on the "loaded" fuel, then go ahead and dilute it down. Easier than tearing into the carb.

[deblen]

Originally Posted by IslandYacht

While running along The carb will start spewing fuel out of a vent on the top. The engine will start running rough and, unless kept full throtle and spewing fuel, will quit. I can limp along by removing the fuel line from the tank and reconnecting when engine falters. Second new carb on engine and all the same problem ultimately. Any ideas?


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"second new carb.....& same problem"

Suggest tank &/or fuel system to carb is contaminated with crud of some kind. Ethanol gas will cause this as will water in tank.
Suggest flushing tank to carb with methyl hydrate (methyl alcohol).It breaks water up into micro droplets & dissolves ethanol crud also. Methyl hydrate is used as gasline antifreeze in the north.

You may find white jelly crud in carb bowl-clean it completely out with MH.

Scrub the tip of float needle with methyl hydrate for same reasons.

Other suggestions re Stabil,etc are good practice also. A teaspoon of MH in the tank is good for keeping water(condensation) broken up so that it will "burn" with the gas.

Cheers & Merry Christmas / Len

[ebsail]

could also be a pin hole in the float so the needle valve is always open.

[svJasmine]

Make sure the float "floats", check needle and seat.

[SeaSon]

Second carb, so shouldn't be the float - my first choice.

But "spewing fuel out a vent on the top"? Should there be a hose or cap on that "vent"?

[a64pilot]

Originally Posted by SeaSon

Second carb, so shouldn't be the float - my first choice.

But "spewing fuel out a vent on the top"? Should there be a hose or cap on that "vent"?

No, the bowl has to be vented to atmospheric pressure for the carb to work, of course there could be a hose so long as the other end is open and unobstructed


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[hamburking]

I'm +1 for needle valve. If you replaced the carb and the problem persists, then its a symptom of bad fuel. Buy a new plastic fuel tank and hose, and new gas from a reputable source.

[basssears]

How old is your fuel tank (not familiar with specific model here but I'm assuming at 5hp we're talking external tank)?

Might be worth investigating if you're getting too much fuel pressure into the system... the way the newer tanks are built for zero emissions they can generate lots of pressure in the fuel lines, maybe blow through the whole carb system.

When you're running and it's dying, have you tried cracking the fill cap on the fuel tank? Does that help? If so you might consider a fuel demand valve like this:
Prevent Engine Flooding with Fuel Demand Valve : Attwood Marine Products®
(I have no experience with it just have read about them).

Good luck (and keep in mind, my advice is worth what you pay for it... the only thing I'm worse at than diesels is outboards...)

-- Bass

[Jrlyons123]

I’m having the same problem. Brand new carburetor, and gas tank and fuel lines. Still having the problem. IslandYacht did you ever figure it out?