74 FJ40 still running terrible... ignition?

[Gator1]

okay...

If that IS a vacuum retarder, It was plugged into the vacuum at the baseplate of the carb.
I capped it off
And I bypassed the resistor, since points have been replaced with the Petronix ignitor.

Just ran it around the block and put a fresh tank of premium. set the timing to about 12 degrees advanced.

Running much better for a couple of blocks... gonna take it out for a longer drive and see what happens!

Doug

 

[Air Randy]

That sounds promising! Let us know how it turns out. If you ever decide to replace that old distributor consider getting an HEI unit. MAF now sells them and the prices have come down to around $250. It will drop right in, requires 1 wire to hook up to switched 12V and will give you a little bit of a performance improvement. It will give you a little better advance curve to make it feel peppier. It also allows you to open up the gap on your spark plugs to .050 so you get a cleaner burn.

And, if you ever need replacement parts you can buy them in any parts store in the US since they use standard GM ignition components.

 

[Gator1]

Thanks Randy, Ricardo, Martin, Uncle Ben!!!!!!!!!

Just that little bit of back and forth really taught me a lot. I look forward to the day when I can chime in on someone else's problem...

Being a poor diagnostician means I tried all the little stuff... It seems like the problem was the retarder/advancer. Still not sure which one it is supposed to be and why it was such a big sudden change.

I guess with these old rigs, every little thing makes some difference.

with the retarder plugged off, my timing stays in one place (advances mechanically anyway)...

This thing is now running better than ever except for bogging down on initial acceleration. But runs under load better, fires right up, less backfiring.

Getting lots of hot spark by skipping the ancient resistor (have the pertonix ignitor anyway) and have the timing in one place makes a big difference...

Now, just may be getting the carb jetted correctly for the altitude

Doug