at high rpm engine misses and breaks up

[inkman800]

3.0 mercruiser i replaced condenser rotor and cap boat at high rpm or medium rpm breaks up and misses runs smooth at idle any ideas would plugs or points cause this

 

[Bigmo83]

Re: at high rpm engine misses and breaks up

Check the fuel pump

 

[SS MAYFLOAT]

Re: at high rpm engine misses and breaks up

Hi Inkman, see that your a fellow Buckeye. Does your engine still have points or electronic. If it is points type ignition, the wrong gap/dwell can cause the missing a sputtering. But check your fuel filters also. A fuel restriction can cause problems of leaning out at high RPM which is not good on the ole power plant. Have you ever been on the Muskingum? Trying to find someone that has. Planning to take a trip on it next year. Good Luck

 

[chesire_catt]

Re: at high rpm engine misses and breaks up

I had the same problem on my 1986 3.0 Mercruiser. It would run great until I hit 28 MPH then would sputter and bog out. You could insert a primer bulb on the line out of your tank and squeeze it as it starts to sputter and see if that does it. With mine the previous owner put in an electric fuel pump and the relay was going bad. so it wouldn't always bog out. once I fixed it, it has been fine. I read somewhere that merc had a problem with some of their compression fuel pumps not being strong enough I know a newer hi volume pump is available. Also check your fuel filters. Good luck!!