Greetings,

I'm posting about a '68 302. It's in a boat but I'm told it's a truck engine, and I'm desperate for advice.

History:

Last year had the motor rebuilt by local engine builder.
Installed factory Ford aluminum four barrel intake and Holley 650
First two times on water, about 30 minutes each, ran good and smooth.
Third time on water, developed vibration, put it up for winter.

This year tried new harmonic balancer, no change.
Check plug wires and found that engine missing on every other cylinder, starting with number one cylinder.
Switch wires from adjacent cylinders, no difference.
Switched plugs from adjacent cylinders, no change.
Check for valve closure, valves closing.
Checked compression, has compression.
Checked spark at plug end of wires, has spark, orange.
Changed points to Unilite electronic,and high output coil, no change.
Double checked spark at end of wires, has spark, orange.
Changed spark plugs, last years plugs dark, but no buildup.
Still missing on every other cylinder.

Help

 

Have ya checked to see if the valves are opening on the missing cylanders

sure ya have the firing order right 1-5-4-2-6-3-7-8

 

Correct,


I re-adjusted the valves on two of the cylinders that were missing, and triple checked rotation and firing order.

It's the every other cylinder that is confusing, as well as that it will start and run on four cylinders, and even planes out and cruises at 30MPH.

 

If you've got a dual plane intake manifold, rebuild the carb. One side
is not feeding gas to the cylinders.

 

Thanks Kruse, I'll check into that tomorrow.

 

That was going to be my second choice (the carb)...

 

Great job guys, it was the carb.


Thanks for the help!

 

I have the same issue as the gentleman who started this discussion. I have the same symptoms and the carb is only shooting gas out one side
i therefore clean the other and still no gas. I spray the faulty side and it works.
yet does not when I don’t inject it.
thoughts?

 

how did you repair the carb?

 

I would rebuild the carburetor; take it apart, use lots of carb cleaner to clan out all the passages. You can point the straw of the pressurized cleaner and put its tip against any of the ports and openings you find and spritz away. Watch for where the cleaner shoots out and make sure both sides do the same. Get a rebuild kit, which usually includes all the gaskets and seals, as you will be scraping the old ones off all the surfaces on the carb.

 

And make sure to wear safety glasses when spraying these passages.