cold spark plug after running

M

mvaughan

Cadet
Joined
Jul 16, 2010
Messages
9
Hello all, I have a 68 9.5 sport win. Cannot get top end when running wot. Seem like it is running on 1 cyl. I have replaced points and condensors, set at .020", rechecked settings. Swapped coils from on to the other, and my bottom plug is cold to the touch after running for a couple minutes. Top plug is hot after same run time. Also have changed plugs.

Engine starts fine and runs great, just no top end.

Could this be a plug wire problem? I have checked continuity and is good.

Thanks Mike
 
S

Solittle

Fleet Admiral
Joined
Apr 28, 2002
Messages
7,518
Re: cold spark plug after running

Don't know your 9.5 but if the top cyl is firing swap the coil and plug wire to the bottom hole. If the problem moves to the top hole you have nailed it.
 
M

mvaughan

Cadet
Joined
Jul 16, 2010
Messages
9
Re: cold spark plug after running

could this be a clogged high speed jet or a compression issue? I plan on testing compression tonight. From what i have read on this site, as long as the pressures between both cylinders are similar, and pressure is above 70 psi, I should be good to go.

I have switched the coils around with the same results.
 
M

mvaughan

Cadet
Joined
Jul 16, 2010
Messages
9
Re: cold spark plug after running

Good news! The motor is running great. The lower plug wire had a split in it. After replacing, motor is running great. However, during reassembly of the stator plate, I screwed up the throttle alignment. Using trial and error several times, still cannot get is set properly. My manual has nothing about throttle set up.

Can any one help?

Thanks Mike
 
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