Boggs down over 85% throttle

[Flying Fish 73]

Everybody has an opinion on this one, but nothing has worked yet....<br />My 1973 Johnson 65 horse starts great, runs at medium speed great, but when we get past the 85% throttle point she starts to bog down and will periodically surge every couple of seconds at full throttle. If we back off and start over she'll run okay up to the 85% point.<br />We've already replaced the gas tank and hose (thought she was sucking rust from the old tank). We did the fuel pump kit and replaced the spark wires. But, still no luck. And, when she's bogging down, squeezing the bulb doesn't do any good either. what's next? Thanks from Texas

 

[aludeidmonkey]

Re: Boggs down over 85% throttle

I have a situation very similar. Look for "1970 40hp evinrude boggs down. Try everything I have tried and see if you get somewhere. My problem has just about been solved. All I lack now is some mixture adjustments while I'm on the water.

 

[Maximum Gravity]

Re: Boggs down over 85% throttle

You didn't mention anything about the carburetors. Did you do carb kits/rebuilds? If you are pretty sure there is nothing wrong on the fuel end, it could be in the spark side. The plug wires are a good start, but you may be getting an electronic break down at higher vibration/temp/rpm. If that is the case, you might check into the coils (cheapest and easiest) then consider the power pack if you still have no luck.<br /><br />I am sure someone with more experience on this particular motor will shortly confirm or deny which is the most likely culprit.