1995 Yamaha 250 3 dead cyl. same side

[sail_tahiti]

I have a 95 250 which it wont run over 13-1400 RPM. I recently took all the carbs off and cleaned them. The boat was sitting before that. All the cyl. have spark but im wondering if maybe on that side the spark is not strong enough? I have been reading the service manual. Any ideas??? Thank you for any information. Also I put six new gapped spark plugs in.

 

[sail_tahiti]

Re: 1995 Yamaha 250 3 dead cyl. same side

Also I changed all three fuel pumps. I have two 250s and the other one is running fine. Thanks for any input

 

[Ray Neudecker]

Re: 1995 Yamaha 250 3 dead cyl. same side

More testing needs to go on. Check compression next. Sometimes a shot of gas or carb cleaner into each cylinder may help diagnose. Check the timing to see if it is advancing properly also.

 

[sail_tahiti]

Re: 1995 Yamaha 250 3 dead cyl. same side

Thanks for the reply. I checked the compression and it is good. I also sprayed a little gas in those three cyl. and tried to turn it over and it still would not fire on that side. Thank you again for the reply