Engine runs shakey when hot

[Striper Blues]

3L OMC runs great at idle and no problem up to crusing speeds for about 15 or 30 minutes then it starts some kind of slight, erratic skipping. I'm not talking running out of gas bogging here, I'm talking intermittent skipping. I have new, plugs, wires, cap, rotor, condenser, points, carburator etc, ... Could this be caused by the coil? It seems I read a lot about bad coils on here, but never had one go bad in a car. Is it because of the heavy 4000 rpm loads?

 

[MooseHootie]

Re: Engine runs shakey when hot

Could be running hot enough to cause the fuel in the carburetor to vaporize and cause it skip.

 

[Striper Blues]

Re: Engine runs shakey when hot

thanks for the feedback. I have changed manifold and carburator along with complete new outdrive water pump, thermostat etc. I initally had an overheating problem but now it runs right on the money on temp gage etc.

 

[Striper Blues]

Re: Engine runs shakey when hot

anybody experience a problem like this? I'm thinking the coil might breakdown when warm? Is this possible/likely?

 

[Boatist]

Re: Engine runs shakey when hot

Could be the coil but easy to check. Hook your timing light up to the the coin output wire and look at the light for skips or uneaven pattern. If it matches your miss you are on the right track. Could also be a valve adjusted too tight and with engine good and hot not closeing or seating.