huntandhook
Seaman
- Joined
- Jul 29, 2005
- Messages
- 58
I'm having some problems with my 1979 40HP Johnson outboard model # 40R79E. The motor starts very well, idles and runs excellent for about 1/2 hour, then it loses power and will only run at low throttle. When I open up the throttle more than about 1/4, the motor loses power and stalls. I checked the breaker points and they are clean and properly gapped. I have the correct sparkplugs and proper plug gap. The fuel pump is also working fine. I also disconnected all safety switches and the runaway cutout switch and this has not solved the problem. The motor has externally mounted ignition coils, could one of these be the cause of the problem? I don't know what else to check. I don't understand why the motor initially runs as good as it ever has, and then starts to run terrible after a while. If anyone has some advice for me on what could be causing this problem, it would be greatly appreciated. <br /><br />Thanks for the help.<br />Phaedo