Logo
FULL SITE MENU

Yamaha 40hp 2 stroke running rough

G

gonefishn

New member
I'm new to boating and hav

I'm new to boating and have a 1996 Yamaha 40hp 2 stroke on my 13' Boston Whaler Scout. It has been in the water through the winter and only run a few times. I recently had to replace the start relay and took it out yesterday. It starts great and seemed to run well at WOT and intermediate settings for a while. After about 15mins it started to run rough and was hard to keep running except at WOT or close to that. It actually sounded like it was running on less than all 3 cylinders. I was thinking it might be a coil or carburator issue. I was planning on pulling the carbs and giving them a good cleaning. Am I on the right track? The motor was really strong last summer so I think it has just has crud in the carbs. Thanks for your responses. GoneFishn
 
"Just-In-Time,

I'll put

"Just-In-Time,

I'll put fresh gas in the tank and see how that does. If that doesn't do it what might it be?"
 
you need to check to make sure

you need to check to make sure u have no water first!!!
drain water separator and dump the fuel out of the filter on the motor
 
"Just-In-Time,

Where is the

"Just-In-Time,

Where is the water separator on the 40 hp Yamaha? I know where the fuel filter is. gonefishn"
 
"I drained the fuel filter, ch

"I drained the fuel filter, changed the gas, changed the tank and fuel line/primer bulb from the tank to the motor. It is running very poorly at low RPM (idle), dies if I try to advance to WOT and seems to run ok at WOT if I can get her there. Do I need to rebuild the carburetors?"
 
Back
Top