64-365hp driveability problem

[Don M.]

I've just done a major tuneup, and now when my 327-365 gets up to 200 degrees it just stumbles and quits running. It will crank fine, sounds like it isn't getting spark, but won't fire. It runs perfect for 20 minutes , gets up to 200 deg, and cuts out. Won't start, might stutter a bit, BUT will not start, wait 5 minutes. It fires right up and runs perfect. Get up to 200 again, and it quits again. Now, I just did , points, condenser, cap, plugs, rebuilt the carb, new coil, new fuel filter, (It never did this before) I am suspect of the points. I will replace them tomorrow. I swear this never happened until I installed a new GM restoration fuel filter. Clogging, ?? vapor lock. I have spark, I have fuel. Well, I believe I have good fuel supply, it backfired and shot a 15" flame, and I'm not so sure I want to look down the carb again. I'm thinking possibly weak spark, or the fuel filter??? Give me some ideas

[Gene M.]

Re: 64-365hp driveability problem

Don,
When it does not start are you getting spark and gas?

If you let it sit and it starts it sound as if the coil gets hot and quits.......

Also check if gas is present when it quits.

Sounds as if you are resuming work on it tomorrow. Be sure to disconnect battery over night.

[Don M.]

Re: 64-365hp driveability problem

It definetly has spark, I just replaced the coil, it had a non original coil in it when I bought it. I believe it was getting fuel, as I mntioned after the big backfire I became a little timid looking down the carb. But I think it has fuel. I'm replacing the points (weak spark)maybe? I think I'm going to replace the fuel filter, I swear this started when I put a new fuel filter on it.

[Dan H.]

Re: 64-365hp driveability problem

Sounds like the vacuum advance may be not functioning, high temps, shut down etc. Try checking timing with and without the VAC connected.

[Timothy B.]

Re: 64-365hp driveability problem

Don,

Before changing parts that may be good keep in mind the motor needs air, spark and fuel to run. Best way to repair the problem is get the motor to quit running.

Check for fuel leakage (flooding) inside the carburetor by looking down to the throttle blades with the key OFF after it quits. If that looks dry, work the throttle to see if the accelerator pump has fuel available as this will give a indication if fuel is in the floats.

Double check for spark at the plugs with a timing light, do this test first. If this just happened with your tune up chances are very good there is a faulty part.

Sounds like electrical problem, when the motor quits, put a test light on both ends of the ballast and with the ignition key ON you should have power on both wires. At that point, install the old coil and see if the problem goes away.

[Dana M.]

Re: 64-365hp driveability problem

You might check the points with a feeler gauge, had a similar problem and my dwell meter was wrong the points were barely opening.

[Chuck G.]

Re: 64-365hp driveability problem

I had a similar problem with a cracked coil. When the engine/coil would get hot, the crack would open up, and the coil would short out......car wouldn't run.

New coil.....no problem. You might try putting your "old" coil back in.

Chuck

[Paul H.]

Re: 64-365hp driveability problem

I agree that trying the old coil may be the answer.

[Larry M.]

Re: 64-365hp driveability problem

Agree with Chuck and Paul regarding the coil. It has also happened to me.

I would also change out the distributor condenser. These have also gone bad with heat/handling and if they short out, the ignition will die. Many of the condensers today are either cheap imports or VERY OLD original stock. Both are prone to problems. ACCEL (current manufacturer) has an excellent reputation for points and condensers for our old cars.

Larry