1999 YAMAHA 115 2STROKE PROBLEM - The Hull Truth

mtpockits · 04-29-2008, 07:31 AM

Spent the last 3 days fishing on our boat, 40 miles a day, boat had been setting for the last 4 month, i do crank it every month and run it, racor is less than 6 month old, plugs changed at the same time.
BOAT RAN GREAT UNTIL MY WIFE SAID HOW GOOD IT IS RUNNING, when we slowed for a idle zone, at that point it was running on less than four cylinders now and snezzing and spitting, like a lean condision.

So yesterday i put the water to it and ran it at all rpm you can safely with a prop out of the water. It ran like a champ. My idea was to run it and the cylinders that were no hot was were i was going to start from there.

Had to drive 100 miles home with motor in up and locked, you think trash came out of bad spot and need to be cleaned out.

thanks kirk

mtpockits · 04-30-2008, 07:31 AM

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A1 Outboard · 04-30-2008, 05:15 PM

Quote:

mtpockits - 4/29/2008 9:31 AM
boat had been setting for the last 4 month, i do crank it every month and run it, racor is less than 6 month old, plugs changed at the same time. BOAT RAN GREAT UNTIL MY WIFE SAID HOW GOOD IT IS RUNNING, when we slowed for a idle zone, at that point it was running on less than four cylinders now and snezzing and spitting, like a lean condision.

you think trash came out of bad spot and need to be cleaned out. thanks kirk

It is possible that stale fuel varnish deposits can loosen up and float around inside the carb, intermittently restricting jets or holes in the carbs.

Another common problem is the steel screws inside the fuel pumps rust and flake off metal which lodges inside the carburetor, usually right under the float valve seats. It got so bad that in 1992 or so Yamaha finally put a brass screw and gasket over a passageway from the fuel inlet fitting to the valve seats. Remove the screw and look inside for trash, varnish, etc. In all likelyhood, you may have to soak and rebuild the carbs and replace the fuel pump for good measure.