Surging-surging

[Paul_Dublin]

Yam 60, 3CYL surges under power (above 3000RPM).<br />I've had them serviced ($400!) and she's fine for about 2 trips and then progressivly gets worse.<br />It has Water seperator, and new fuel tank with new hoses and connectors.<br />Fuel pump was replaced and Carbs completely stripped down and cleaned (by shop).<br /><br />The sister motor beside doesn't get any such problems on an identical setup.<br /><br />Could the oil injection be fouling the carbs?<br />Any thoughts on what may be causing the motor to surge (Electronics trouble?)

 

[rodbolt]

Re: Surging-surging

most likly its still fuel. the oil is injected begind the carbs so there is no oil in the carbs.<br /> the connector on the engine side bolted to the pan has been known to give problems. its easy to bypass. but most surging with no alarms is fuel.

 

[Paul_Dublin]

Re: Surging-surging

What connector is this?<br />Is this the connector on the Small fuel filter before the Pump, or the actual connector to the fuel tank?<br /><br />Thanks

 

[rodbolt]

Re: Surging-surging

its the connector at the lower cowl. the one the tank line plugs into. it has an oring in it that swells sometimes.

 

[FHARVELL]

Re: Surging-surging

Your fuel tank venting may also be a possible problem. I had a dirt-dobber(bee) nest in my fuel tank vent flang (50 gal). Caused the motor to surge above 3000. I had to go through the deck (skill saw) under the console, disconnect the line and take a screw-driver to clear the clog in the tank. Plus I had to blow out the vent line that feed over the side with some LP air. How did I check this, I tried to blow air into the fuel tank vent and discovered it was clogged solid, also, I couldn't put more than a gallon of gas at the time in my tank. I would not recommend tring to blow LP air into the tank unless the line is disconnected or you could inadvertanly pressurize the tank which will lead to big trouble when you go to take the gas cap off. If you have a portable tank, you might check to see if the tank develops a vaccum when your having this problem. Most portable tanks have that little vent screw on the combination fuel guage/cap. Anyway, that cured my surging problem.

 

[Paul_Dublin]

Re: Surging-surging

Have changed the fuel connectors for genuine Yamaha types. Have replaced water seperator and using a new tank (that causes no problem on an identical motor).<br />Still have the surging problem!<br /><br />I have also tried pumping the bulb when it surges and it still surges.<br /><br />Any other suggestions?