no wot sometimes

[randyd9546]

I have a 1987 yamaha 25sh which is a 2 cylinder single carb,it runs fine most of the time but sometimes when you take off it will only get about half throttle and just boggs,you can let off and let it idle or kill it just for a few seconds and take off and it is usually fine again.I have replaced plugs 3 times changed fuel tanks,rebuilt carbs twice the second time added a in line fuel filter and pumped line to clean before installing hose,added new fuel tank,fuel line with new bulb,no help,grounds are good on coil no leaks,does not help to pump bulb or choke,i found it didn't have a thermostat so i installed one and decarbed with merc spray but it has been raining so i can't see if that helped.I just bought motor this fall PLEASE HELP.

 

[Yepblaze]

Re: no wot sometimes

Probe the main jet for hardened debris.

 

[randyd9546]

Re: no wot sometimes

Thanks for the suggestion.I ran wire through all jets then looked through them all clean.

 

[Yepblaze]

Re: no wot sometimes

How about the tube above the main jet? On many japanese motor carbs they drop out (with some persuation) and have special holes all over em. Called an emulsion tube.<br /><br />Also I believe some import motors had seperate low speed and high speed coils under the flywheel, if so perhaps it could be dropping the high speed coil. Does it allways fall off at the same RPM or can you massage it to get a little more out of it?

 

[randyd9546]

Re: no wot sometimes

same rpm,it has 1 coil on the outside with both plug wires coming out but i havent pulled the flywheel.it is confusing because it will fly when is is running right.it is on a 14 ft jon boat and will run about 32 with 2 people in it

 

[randyd9546]

Re: no wot sometimes

THE TUBES ARE CLEAN INCLUDING ALL THE SIDE HOLES<br />ALSO

 

[randyd9546]

Re: no wot sometimes

please any suggestions