1981 35hp misses under load at high speeds

[Flash214]

Hello everyone,<br /><br />I am new to the board and have just bought a little fishing boat.<br /><br />The engine had a bad prop on it when I got it (Rubber spun out). I put the spare prop on it and now it seems to miss at higher speeds or when I am at high throttle positions. I don't know if this is load related or not but it does it whether there is one person or 4 in the boat. I thought it was a gear case problem but I pulled that last night and all looks good. No worn teeth or anything. I am not sure were to start. It seems to do it in 15-20 second intervals but it is just a quick miss then back strong again. It is enough to make the engine jerk and kick though.<br /><br />Sorry this is so long but can someone tell me where to start. Plugs and wires look good. Runs great at all other ranges like idle and slow cruising speed.<br /><br />Thanks for the help,<br /><br />Flash

 

[inohv8]

Re: 1981 35hp misses under load at high speeds

I had a similar problem.. with one of my engines.. Do you know if the carb(s) are clean? or at least the high speed jet(s), if it misses the fuel even for a second, it will drop and come back.. another thing is to check the timing, usually the timing at high speed is critical, it has to be bang on to run properly, you can also do some damage if it fires at the wrong point which will give you a kick, like hitting a rock then runs ok again..<br />sound familiar?<br />stan

 

[Flash214]

Re: 1981 35hp misses under load at high speeds

Yeah, that sounds like what it was doing and now is doing again. I had the gearcase apart to check everything with it and everything looks greats. Hardly any wear. I adjusted my shift cable and replaced the plugs with new ones.<br /><br />When I put it back in the water it seemed like the problem was solved. It ran like a top for half the day...then back to the missing. It feels just as you explain...like hitting a rock. I will pull the carb. and check the compression and timing tonight.<br /><br />Thanks for the reply.