Missing and hesitation, only after a hot start

[Fairview]

I hope you don't get tired of hearing from me, but I've put 300 miles on my 3000 in less than a week, so finding plenty to ask about.

Here's a mystery I can't solve: My engine runs smoothly and with no issues unless I have parked it for a few minutes while it's good and warm.

From a hot start (where the temp gauge has climbed over 190 degrees from just sitting, with the engine shut off) it will miss and pop. I am able to drive it, but it is missing quite noticeably, not an even miss like a fouled plug, but an unpredictable miss. It seems to stay that way until it cools down, or I shut it off and leave it.

Next time, after the engine is cold, starts up, runs beautifully, I could go 100 miles without issues. Then if I park for a while, engine compartment gets hot from just sitting there, then it misses again.

Any ideas? Thanks very much, Jeff

Here's an unrelated photo, so my post doesn't look so boring!

 

[steveg]

Sounds like typical hot flooding. The heat from the engine boils the gas out of the float bowls into the manifold.

I wonder if the ethanol in the gas makes this worse.

 

[BoyRacer]

What creates this problem is that the intake manifold and exhaust manifold are bolted together. Another good reason for putting headers on your Healey.

 

[nevets]

possibly a bad coil

 

[Fairview]

possibly a bad coil

I wanted to report back that yes indeed- a bad coil. To recap, my 3000 would run beautifully until it got good and warm, then miss unpredictably, still driveable but a very noticeable miss. I had avoided replacing the coil as I'd never had a bad coil in all my old car years, so doubted that as the cause- shows I was wrong.

I put on a new coil and it now revs smoothly even when warm. In my research, it was suggested that an oil-filled coil should not be mounted horizontally as it is more prone to going bad due to the oil not covering all the innards! I don't know if that is true or not, but I thought I'd mention it. Of course I put mine right back where it was atop the generator.

Anyway, Nevets, you were on the mark. Many thanks, Jeff

 

[homebeforedark]

From my experience about ten good coils are replaced for one bad one. Same with bulbs . I always suspect something else but every once in a while a bulb actually burns out.

 

[John Turney]

Thanks for getting back to us with the solution!