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Re: Engine Warms up and wont stay running

Posted: Mon Aug 05, 2019 1:04 pm
by jralbert
Another non-gear-head response based on observations here over a long time: This seems heat related. Something heating up and failing. What's likely culprit? Is vapor lock an issue?

Re: Engine Warms up and wont stay running

Posted: Mon Aug 05, 2019 2:48 pm
by Busia
Yes, it is heat related. If it is vapor lock you won't have fuel in the float bowl and the accelerator pump won't squirt fuel. My guess is no spark, and the ECM is bad. It's the module mounted on the fire wall if it was a Dodge pick up. Yours will be nearby. Easy to change and you should have a spare anyway. Napa or any auto store has them. Search this site for more info on them, been lots of discussion on them.

Re: Engine Warms up and wont stay running

Posted: Mon Aug 05, 2019 3:49 pm
by jralbert
Just a little more than a yr ago, the same kind of query popped up with replies from the same varmints - you might find it useful (or at least, interesting)
viewtopic.php?f=27&t=1425&p=10196&hilit=stalling#p10196

Re: Engine Warms up and wont stay running

Posted: Tue Aug 06, 2019 6:12 am
by Fastjeff
You have to determine if the motor still has spark when this happens, to narrow down what's going on here.

Jeff

Re: Engine Warms up and wont stay running

Posted: Tue Aug 06, 2019 7:46 pm
by tedurocher
okay, back at it tonight. I swapped parts to see if I could the problem to follow from one engine to the other.

coil, ignition module, breaker plate that contains the pick up coil and nothing really changed until . . . . I swapped the rotors. The stalling switched engines then. I put my spare rotor on from my last tune up and it fire right up and hasnt stalled since.

Re: Engine Warms up and wont stay running

Posted: Tue Aug 06, 2019 9:13 pm
by jralbert
Thnx for the followup (some folks don't do that) - are rotors subject to heat failure?

Re: Engine Warms up and wont stay running

Posted: Wed Aug 07, 2019 9:20 am
by ddependo
I believe Some electronic ignition systems require internal resistance coil and some do not . might check that.
Good luck.
Wayne

Re: Engine Warms up and wont stay running

Posted: Wed Aug 07, 2019 11:40 am
by Fastjeff
If those are the original distributors, there are two different rotors and caps that are NOT interchangeable.

Guess how I found that out!

Jeff

Re: Engine Warms up and wont stay running

Posted: Fri Aug 09, 2019 7:37 am
by Fastjeff
Yes, Alice, you can teach an old dog new tricks!

Learned one just this morning on my Mercruiser 305 V-8, that was apt to cold stall after going into gear. (Very embarrassing at the ramp!) Here's the deal (and it translates to Mopar distributors and others): The electronic module in the deal bumps the timing 2 degrees when the motor reaches 1,000 rpm. Not realizing this, I had timed it at that rpm, which made the motor 2 degrees retarded. I retimed it just now with the idle speed on 700 rpm, then reduced the idle speed to get it back down to 700 rpm (it was at 1,000). The timing was STILL retarded, so I went through the exercise again, eventually getting my 8 degrees advance at 700 rpm. Motor sounds much now and I'm sure the cold stall issue will be gone.

Jeff

Re: Engine Warms up and wont stay running

Posted: Fri Aug 09, 2019 8:18 am
by Fastjeff
Addendum (really dumb!):

Lying there in the tub (where I get my best inspiration) I realized I had also made this dumb *ss mistake on my Marinette, which had "mysterious" hot stalls the entire time I owned it. Grrrr!

The bottom line here is: When You (or ?) is timing your engine(s), have a helper keep an eye on that tach! If the idle speed increases above, say 600-700 rpm (less is better), then turn down the idle speed at the carb and retime it. I had to go through this iteration several times before advance and idle speed was correct.

Hope this solves some problems for y'all out there (I'm a southern now).

Jeff (pronounced 'Jay-F' around here)