Engine shutdown after 20 min... wait 15... starts...then shuts down after 8 min

[Candc27_CarteBlanche]

Good day, new to the atomic 4. Recently bought a candc 27 with an atomic 4, electric fuel pump and electric ignition.

Engine starts great and runs smoothly, shutsdown after a cold start as if you turned a key after 20- 30 min. Will not start again for 10-15 min. It then starts and runs smoothly until again it shutdown after about 8 min... rince repeat.

The fuel pump has a opss connected to it but the previous owner seems to have bypassed it by connecting the two terminals with a jumper wire. I removed the jumper cable and was able to measure power at both terminals of the opss until the engine shutdown so I dont believe it is killing the fuel pump.

The fuel filter always has some air in it when the engine has stopped. Is the fuel pump shutting down?

The fuel pump feels hot to the touch. Should it be hot?

Mechanic here suggests replacing all fuel lines, installing fuel/water seperator and changing fuel pump.

The abrupt shutdown (like a key turn) made me think electrical. It doesnt cough or sputter like its runnjng out of gas but I am new to the game so what do I know

[Al Schober]

Sounds like a classic case of the spark coil failing. The electronic ignitions are hard on coils, and some folks use a ballast resistor to limit coil current. I have zero experience with electronic ignition, but there are lots of threads on this BB that deal with that issue.

[Dave Neptune]

I agree with Al. You could let her run until she dies and then check for spark.

The engine shutting down like the key was shut off is indicative of an electrical failure of connection. The "fact" that it starts up after "cooling" down a bit and then dies again is a classic coil failure.

Check some of the threads regarding the coil issues and don't get caught up in the technical stuff. You will need a new coil and a resistor for it. My suggestion is buying them from our host or Indigo and be done with it.

Dave Neptune

[Administrator]

The fuel filter always has some air in it when the engine has stopped.

Let's come back to this after you've followed the advice re the coil.

Bill

[ndutton]

Al's and Dave's comments are spot on. There are several threads on the subject but as we have seen recently, they can be unnecessarily confusing with technical geekoid stuff.

Here is a thread that hasn't been polluted yet:

http://www.moyermarineforum.com/forums/showthread.php?p=113955

[Candc27_CarteBlanche]

Thanks for the quick replies! Will try to get out to test the coil this evening.

Previous owner made a comment he had rellaced the spark plugs but he had not gapped them correctly but was sure it was not an issue.... will this have an impact?

[ndutton]

Thanks for the quick replies! Will try to get out to test the coil this evening.

While there, please measure your alternator output with the engine revved up a little and report back.

Previous owner made a comment he had replaced the spark plugs but he had not gapped them correctly but was sure it was not an issue.... will this have an impact?

No, but get them right anyway.

Mechanic here suggests replacing all fuel lines, installing fuel/water separator and changing fuel pump.

The mechanic is guessing on your dime. How much($) to heed his suggestions?

[Dave Neptune]

No the gap will not cause a shut down. Do inspect the plugs and set to about .040 as you have an EI. The gap only influences the fire at the tip which starts the whole power stroke. The EI produces a consistent spark unlike points so additional gap can be utilized for better overall performance. Points are only "Correct" when set correctly and wear out from the "start", unlike the EI which has a consistent "dwell". Also the "cam" in these old distributors are pretty much worn out so setting by gap is useless and a dwell meter is necessary!

Dave Neptune

[Candc27_CarteBlanche]

Tried my best to test the coil , waited for the engine to fail then disconnected coil to check for spark. Seemed to work.

Mechanic showed me base of spark plug was dry from lack of fuel. Went ahead and let him change the fuel pump.

Ran for 1h and 15min no issues. Seems to be resolved. No idea why pump went bad thou
gh.

Thanks everyone for the help and quick replies. You guys are a great resource!!

[joe_db]

Please consider the Moyer alarm panel system or a fuel pressure gauge.

[edwardc]

...No idea why pump went bad ...

Another victim of the "stuck ball" syndrome?

( for reasons that yet to be determined, sometimes the fuel pump's check valve ball starts sticking to its seat.)

[roadnsky]

Another victim of the "stuck ball" syndrome?
( for reasons that yet to be determined, sometimes the fuel pump's check valve ball starts sticking to its seat.)

The fuel pump feels hot to the touch. Should it be hot?

Although mine has never stuck and I'd think that I'd have the hottest of the bunch?

[ndutton]

Jerry, it’s been a while since we talked about your hot fuel pump. I’m transferring fuel right now, so far a 20 minute run time with the electric pump at full flow (1 gal @ 3 minutes) and the pump is cool to the touch. With the engine running and the pump pushing against a closed float valve (flow rate = 1 gal @ 60 minutes) the pump is much warmer. I’m sorry I don’t have my IR temp gun handy to measure. It’s clear that flow rate makes a significant difference.

[roadnsky]

Jerry, it’s been a while since we talked about your hot fuel pump. I’m transferring fuel right now, so far a 20 minute run time with the electric pump at full flow (1 gal @ 3 minutes) and the pump is cool to the touch. With the engine running and the pump pushing against a closed float valve (flow rate = 1 gal @ 60 minutes) the pump is much warmer. I’m sorry I don’t have my IR temp gun handy to measure...

Yep, it's been 9 years!
Your post sent me back to that old thread and I re-read it.
(Old memories for sure)

It’s clear that flow rate makes a significant difference

Our extensive testing back then I think proved that very point.