2005 Yamaha 25hp 4 stroke - F25ESRD CARB PRIME STARTER??- HELP!!

[tawd77]

Hi I recently purchased a boat with this motor on it. It ran fine for the first few outings. Then it had slight hesitation when coming off idle, but would clear up and get to WOT no problem. Well, I took the boat out yesterday morning, and the motor would barely run. it would crank and crank and crank, then start and idle super rough. Then it would usually die again. We finally got it to stay running, and pulled away from the dock. Got about 100ft from the dock and it died. Finally got it started again, and it just spitted and sputtered at idle, and would die if you gave it anymore throttle.

I pulled the fuel line off at the carb, and it has great fuel pulses when cranking. It has a firm fuel bulb on the line also. If you use your fingers, and cover half of the air inlet for the carb, it runs really good. So basically, it is needing more fuel.

I got to looking at the motor wondering why there was no choke. I saw 2 wires going into something on the top of the carb that I thought may be the electric choke. I removed it, and turn the key, pushed the key in, tried starting, and this little valve never moved at all. I came home and read that its a PRIME STARTER. Is there any way to test this? I noticed that if I raise and lower the valve in the carb manually, I can get the engine to run nicely. But it doesnt seem to work on its own.

Does anyone know how to test the prime starter? Or have an idea how it should function?

Thank you!!

 

[99yam40]

Re: 2005 Yamaha 25hp 4 stroke - F25ESRD CARB PRIME STARTER??- HELP!!

Pushing the key goes nothing on a prime start motor.The needle closes off the passage after it warms up.
Sounds like you are in need of a carb cleaning.
Do a forum search on prime start, there have been a lot of posts on the way it works.

 

[tawd77]

Re: 2005 Yamaha 25hp 4 stroke - F25ESRD CARB PRIME STARTER??- HELP!!

Hi, Thanks for the reply. After an hour searching the forum, I dont think the prime start is the problem. Maybe the carb is just gummed up. I will pull the carb, clean it, put new plugs in it, and fresh gas. Hopefully that will fix er up. Thanks again

 

[skipper123]

Re: 2005 Yamaha 25hp 4 stroke - F25ESRD CARB PRIME STARTER??- HELP!!

Did you get it fixed and what was the problem. My 03 25hp 4stroke is doing the same thing. Have pulled carb 4 times and cleaned but still have not found the right spot to clean I guess.