riverghost
Recruit
- Joined
- Jun 27, 2005
- Messages
- 2
Hello, I have a 1999 Yamaha 40hp outboard jet that is losing power and RPM at full throttle. The model number 40MJHX with tiller. When I give the motor full throttle max power and RPM is achieved and after about 20 seconds the engine slowly loses power and RPM. If I reduced the throttle to nil and crank it back up to full throttle max power and RPM are again achieved. There is no problem at slow speeds or idle. I figured it was a fuel starvation issue and replaced the fuel primer bulb in the gas line and checked all lines/connections for leaks and found none. I have also cleaned out the fuel filter. When I remove the gas cap while running there is still a problem. Also pumping the primer bulb while running does not help. Is it the fuel pump or carbs? Searched and tried everything on this site. Thanks any help is appreciated.