Spark plug gap

[stusugg]

Hello. Anyone know the gap setting for a yamaha 9.9 four stroke spark plug? It idles really well, but sputters pretty bad when it's opened up.

 

[rodbolt]

Re: Spark plug gap

can ya post the model number so we can ID the year ?

 

[stusugg]

Re: Spark plug gap

I don't have a model number. I was hoping it was generic. It's a 9.9 Yamaha 4 stroke circa. 1999. Right now the gap looks pretty wide and I think that's what is causing it to sputter at full throttle. Any ideas without the model number?

 

[swist]

Re: Spark plug gap

Nothing replaces the exact spec for the exact model, but I'm had several Yam engines and they were all 1mm gap (.039 inches).

 

[Ray Neudecker]

Re: Spark plug gap

Sputtering at full throttle is normally a fuel restriction. Sounds like time to clean the carb.

 

[stusugg]

Re: Spark plug gap

Thanks, I'll check the gap and clean the carb again.