1979 Evinrude 140hp running funny lol

Okay, so last time i took the boat out, my whole shot was great but once i got to top speed i was at top speed for about 5-10 seconds and then the motor just suddenly bogged down I have checked my hoses and just replaced my fuel line and primer bulb and installed an inline fuel filter after the problem started and that didn't fix it, could my fuel pump possibly be going out? I had a mechanic listen to it and he thinks maybe i either got a bad batch of gas or i could be getting air in somewhere but I can't find any leaks and am starting to lean the fuel pump. when the motor would bog down, if i put the motor back into neutral and then throttle back up, it is just like before good whole shot plane out and then top speed and them bam bog down... and as long as i don't go completely full throttle it doesn't happen...
Anyone have any other ideas i can troubleshoot with?

Re: 1979 Evinrude 140hp running funny lol

Start with the basics checking your compression and spark that will jump a 7/16 inch gap. If you know that that is good then try to use a portable gas can with fresh gas/oil in it. Once you take it out if it starts to bogg have some one pump the fuel bulb, this will replace the fuel pump for getting fuel to the carbs.
It sounds like it could be either a fuel problem or an electrical one where you are dropping a cylinder at high rpm's. Start with the basics and then move on to the more complicated test.

Re: 1979 Evinrude 140hp running funny lol

Well, i sure hope its not electrical, the motor has like 25hrs on the rebuild and my stator trigger and coil packs all changed, new spark plugs installed month and a half ago was running fine then, had the timing checked under a light and that was fine... it was acting up just before this where i would slowly loose power and like you said i would hit the primer bulb and it picked back up, and i was also getting air in from the hose so i bought a new one and when it is bogging down pumping the primer bulb doesn't do anything...

Re: 1979 Evinrude 140hp running funny lol

Sound like a weak fuel pump. Can't supply enough fuel to keep it running at high rpm. When they start to fail, it is common for them to run high rpm for a short period, then go to idle while the carb bowls refill, then take back off again at high rpm. If you constantly prime the fuel hose bulb (forces fuel into the carbs), and it runs high rpms ok- I'd replace the pump.

Re: 1979 Evinrude 140hp running funny lol

It has taken me a long time to be able to even look at my boat.... I really hate working 2 jobs... I haven't been able to get a new fuel pump or rebuild it yet but.... I think I have finally found my problem but not sure if what I found would cause this... I fired the motor up last night while i had a few moments to tinker on her and I noticed she was idling a little high... when I pulled the cover off I felt around on the cables and linkage and I found that the cables were slipping out of the bracket so the motor wasn't going back to proper idle level... So for now I have strapped the cable in place with some sturdy zip ties and am going to take her out and see if she still boggs down.. either way I plan on replacing the throttle/shift cables and rebuild the pump... would a loose throttle cable cause the motor to bogg down after trying to reach full throttle?