4.3L dies as if key shut off when hot.

[took-the-red-pill]

Hi folks. Thanks in advance for any insights here.

The Engine:
1988 OMC cobra 4.3L V6, 175HP(I believe). 2BBL carb. Manual fuel pump. Old school all the way.
In the last month it has had a complete tune up, carb kit, and even a starter.
When operating, oil reads about 45PSI. Temp about 160 or so. Battery reads 14V.

The Problem:
Starts and runs like a champ, Buckets of power. Smooth, no misses, chugs, burps, farts, or anything.

Last time I had it out I'd had it going for maybe 10 minutes. I was running at about 3000 RPM across the lake. It just died. The best analogy I can come up with is that it's as though I turned the key off.
Tried to start it. I would pump it a few times and leave it in neutral. Start it up. It fired right away, jumped to about 2-3000RPM as if happy and running perfectly, for 2 seconds. Then died as if I turned the key off. I did this maybe 15 times with identical results. Still no chugs, burps. No running rough. It just dies as if a switch is turned off.

Tests done, actions taken:
1-Accelerator pump squirts as if the bowl is full.
2-I took off the fuel line, unhooked the coil, and cranked. It squirts a healthy amount of fuel even just with the starter.
3-Others had mentioned that a coil can do that, so I replaced the coil.
4-Started and idled for 10 minutes in my driveway with muffs. Ran fine with the new coil.
5-Took it out on the water with identical problem to above. Got warm, shut down. It did it both in gear, and in neutral.
6-I checked the ignition key. It seems in good shape, and anyway it shouldn't be affected by an engine heating up10 feet away.

Some had mentioned a "low pressure oil switch" which can malfunction, but I can't find any such switch, either on the engine block or on a schematic of the electrical system-granted, I'm no pro at reading schematics.

Something is turning out the lights on me.
Any ideas? Insights? Similar issues out there and their resolution?

Thanks y'all
Keith

 

[jbetzelb]

If they replaced the points and the capacitor with the tune up it is possible the new capacitor was bad. That could shut you down when it gets warm. It will cost like 10 bucks to put on a new one and see if it solves the issue.

 

[took-the-red-pill]

Hi there,

Thanks for the reply. My neighbour came over and we took off the distro cap and BEHOLD! My points were completely shot, a hole right through the contacts where it's supposed to be solid. Looks like we found the culprit.

The problem is that when I asked my mechanic to do a tune up on it, I assumed that meant he would do an complete tune up on it...He just did a carb kit an obviously never pulled the cap. Now I have to go check the invoice to see what he charged me for.

Thanks y'all