1984 evinrude 50hp intermittent low power

[skeeterss1]

I recently bought a boat with a 50 hp 'rude and I've been having issues with it losing power at higher rpm's. It starts and idles great but after running for a while at speed it falls on its face and sounds like its starving for fuel. It will get the boat up on plane fine and 1-10 mins later it drops rpm's and won't go over about 6mph. After the problem starts if you let it idle for a minute and go back to WOT it runs perfect again but only for a minute at best and goes back to low power. When the issue occurred the first time I tried pumping the bulb to see if that would help and it was hard as a rock, I couldn't budge it. It never has any issue running at low rpm's or even running at max high idle just no power at higher rpm's in gear. I checked the fuel filter which was clean and don't know what direction to go next. I'm an auto mechanic but don't have much experience with outboards. Any help would be much appreciated, Thanks in advance.

 

[bonz_d]

Re: 1984 evinrude 50hp intermittent low power

Could be a dirty carb or an overheat problem. Right now I don't have my manual handy to look it up.

 

[skeeterss1]

Re: 1984 evinrude 50hp intermittent low power

I originally assumed carb issues also but would that cause it to be intermittent? If the main jet(s) were partially plugged I would think it would happen all the time not on and off. It also didn't seem to be overheating, It had a good stream from the water pump with no steam or signs of overheating. As I said originally I am not very familiar with outboards just following what I know from working on cars.. Thanks for the response.

 

[Daviet]

Re: 1984 evinrude 50hp intermittent low power

All the fuel must pass through the high speed orifices, if they are plugged or restricted it can cause that type of problem at high speeds.

 

[bonz_d]

Re: 1984 evinrude 50hp intermittent low power

Could be any of a number of things too. Loose/dirty wires, faulty fuel lines, even a voltage control going bad and overheating.