Yamaha F50 '02 w/ "dead spot"

[joedawg]

I have a '02 Yamaha 50 four stroke that has two problems that might be related... First problem is that it has a "dead spot" on the throttle... About halfway forward, just before enough power to plane out, the motor, when agressively moving the throttle forward, has a dead spot that stalls the engine... If proceeding at a gradaul pace thru this "dead spot" then just a slight hesitation... Also, the engine does not like to start when cold... Need to keep pumping the primer bulb to keep a good flow of gas into the engine... Any suggestions out there?

 

[Ray Neudecker]

Re: Yamaha F50 '02 w/ "dead spot"

Apparent fuel restriction, I would suspect fuel pump or carb problem. Trying priming with the cowling off and see if fuel leaks out of the carbs. This would indicate a sticking needle valve.

 

[joedawg]

Re: Yamaha F50 '02 w/ "dead spot"

I did prime the motor with cowling off and there was not any leakage... Using the boat the past few times, I have been able to start it with now with no problem... I must lift the idle throttle to full and she starts on sometimes the first, but almost always on the second turn of the key.... I am still having the dead spot issue when I move the regular throttle forward in a manner other than slow... I have alwasy been hauling other trailers when heading up and back from the lake so its been hard to get the boat home... I might just have to "bit the bullet" and take a quick trip to get it in to a shop but am wondering if there is one more thing to try...

 

[rodbolt]

Re: Yamaha F50 '02 w/ "dead spot"

hello a thourough inspection of the linkage and then the accelerator enrinchment circuits. your engine is also equipped with prime start. DO NOT use the warm up lever to start. if it wont start with the lever down its broke. get it fixed. the carbs are rather touchy on the 50 and without a manometer almost impossible to set up correctly.<br /> good luck and keep posting

 

[rowbards]

Re: Yamaha F50 '02 w/ "dead spot"

sounds like a pilot jet adj. to me...I've had a few of these with the f/t50. some i've found to be completely closed...