fuel pouring out of carb

brentjsimm

Cadet
Joined
Jun 3, 2011
Messages
20
short background: 1990 70hp yamaha, 3-cylinder, 2-stroke. boat wasn't run for about 5 years, so i cleaned the carbs, changed all fluids, plugs, impeller, and everything else i could find. i bought a manual and did everything to the t, b/c i'm anal that way. boat cranked up like it was brand new the first time i tried. BUT, i noticed fuel coming out of the front, air intake, of the carbs. there was quite a bit of it too. not long after the boat ran (maybe a few minutes with the muffs), it died out, i'm guessing it flooded b/c it wouldn't restart until the next day. took off the plugs and they were wet. next day, same thing, lots of fuel. my guess is my carbs need to be cleaned again? or do the jets need to be adjusted? i turned them out 1.5 turns per the manual. a few suggestions would be much appreciated before i break the carbs down again, or torch the entire boat, whichever comes first. also, the bulb does get firm when pumped.

also, the first time i ran the motor, i had a great **** stream, but it gradually got weaker. today, 3rd time running the motor, there was barely any coming out. i was watching it closely, and didn't run the engine but about 15 seconds when i noticed that. broke down the lower unit and the impeller is fine. took the pee stream exit hose off, blew through it, and it was clear. could this perhaps be the thermostat? i suppose i could test it in some hot water, but just in case it comes back fine, i would love a suggestion or two here.

thanks guys for the help.
 

James R

Commander
Joined
Feb 1, 2007
Messages
2,679
Re: water pouring out of carb

Re: water pouring out of carb

Carb problem could be bad needle valves or floats not set correctly.
Water problem could be a blockage, a piece of old impeller or even bugs. Remove the lower unit and the thermostat housing and try flushing down and up with the garden hose.
 

ADK_Boater

Petty Officer 1st Class
Joined
Jun 29, 2010
Messages
217
Re: water pouring out of carb

Re: water pouring out of carb

You should have a tell-tale (****) stream whether or not the thermostat is functioning properly.

If in fact your waterpump is fine, and you have no **** stream, then it would be safe to say that you probably have some blockage.
Start right where the stream comes out and gently use a pick set to pull out any debris if present.

If there are any hoses, then disconnect and check those too.
 

brentjsimm

Cadet
Joined
Jun 3, 2011
Messages
20
Re: fuel pouring out of carb

thanks for the help guys. just a follow up

the needle just wasn't seated well in the carb, so it was staying open and allowing fuel to overflow. i did the upside down blow test, which i didn't do after cleaning them, and it worked perfectly after putting it back together.

the water flow issue is a kick yourself in the arse moment. i took the hose off the exit nipple, and blew back through the engine.....great air flow. i was bewildered. checked the thermostat, and it was fine. THEN, after your replies, checked the simple little plastic outlet nozzle. it was clogged. i probably should have checked that first. oh well. thanks for your help.
 
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