Intermittent / Weak Spark

[GregG48203]

compression test

The compression numbers are good, so that should rule out a bad head gasket or burned valve. If the timing chain checks out okay, then proceed to the top of the engine: look for leaks at the intake manifold.

 

[CusTim]

If you are doubtful of your ignition 12 volt supply I highly recommend a dedicated ignition relay to offload the ignition switch contacts. This is a very inexpensive upgrade and very easy to do. If you end up rebuilding the carb, the best kitt comes from Rock Auto. Do not, under any circumstances trust the cardboard float gauge that comes with the kit. It'll get you in the ballpark but it's not ideal. These carbs are sensitive to float levels and "trial and error" by removing the top of the air horn to reveal the exact fuel level in the bowl is the best way. I installed an MSD distributor once that required the gear to be removed and a brass gear installed. The information to do this came from the cam manufacturer and it can go the other way to. Has to do with premature wear or self destruction.

I like the idea of a dedicated ignition relay - thx. I have a couple more checks on the distributor / timing chain and if all is good there I will be moving on to the carb / intake so thx for thr heads up regarding quality kits. "Self destruction" doesn't sound fun lol. I will contact the mechanic that installed the MSD and see what he did with the gear - if anything.

 

[CusTim]

The compression numbers are good, so that should rule out a bad head gasket or burned valve. If the timing chain checks out okay, then proceed to the top of the engine: look for leaks at the intake manifold.

Well there is some play in the timing chain but I am not sure exactly how many degrees of play. I read in a different post one of the guys said if there is 1/8 of a turn of slop then that is too much. There definately isn't 1/8 but probably about 1/16 or a little more of a rotation - would this be out of spec? I also read in a different post that your timing mark jumping around when setting the timing is tell tale of a stretched timing chain. When I set the timing a couple months ago I don't remember the mark jumping around at all, so I am not sure what to think about my timing chain.

 

[GregG48203]

timing chain

The last car I had with a loose timing chain had a wobbly engine speed at part throttle. It would also flood quite easily, but I suspect it also had a weak choke element (electric). You may also have multiple issues; the spark plug fouling may be unrelated to the starting/drivability problems.