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Intermittent sputtering

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nevets

nevets

Jedi Knight
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Took the Healey out for a spin and experienced some engine sputtering. It started once the engine got fully warmed up, and not under load (as in climbing a hill). It would sputter when stepping on the gas after coming off a downgrade (fourth gear, foot off the accelerator). Car would sputter, like it was starved for gas, nearly die, then it would clear up and all would be well.

I’m thinking it’s possibly dirty carburetor float valves? Maybe a dirty fuel filter? A few years back I replaced the float valves with Gross Jets (due to overflowing fuel issue).

Any thoughts/suggestions will be appreciated.
 
Fuel filter...replace mine every year....even though I have a "new" tank..I am still filtering out kernels from the tank..

Pete
 
HI Nevets, My thought is you might want to look at the floats and check for dirt in the float bowls of the carbs.---Fwiw-Keoke
 
Thanks for the comments
As for debris accumulating in the float bowls, I hope it's not a symptom of a rusty gas tank!?
 
Follow up ...

I cleaned out the float bowls (which were fairly clean), soaked/rinsed, and blew out the jets. Replaced fuel line filter and float bowl gaskets. Did not see any fuel filter screens BTW? Noticed an improvement, but after about 15-20 min of driving, the sputtering occurred again and persisted intermittently, especially at low rev, but not as severe as before.

I'm ruling out ignition issues on the grounds that it would be apparent at start up, not just once warm.

Any other thoughts? Vacuum issues?

Thanks
 
Hey Nevets,
Might consider looking at the coil. I had a MG TC that started with the same
symptoms and turned out it was the coil going bad. Have no idea on how a coil
goes bad or even starts to go bad but once I replaced it, the sputtering on
the TC stopped ! Worth a look anyway. Good luck, these kinds of problems
will drive you nuts.
Regards,
Mike
 
I'd vote for the coil too. Happened in my 1971 Alfa. I'd drive maybe for 30 minutes, started sputtering. I'd pull over, open the hood and the cooling air would revive my failing coil for another 3o minutes. Took me about 10 tries of parts replacement and adjustments to finally fix it.
 
nevets said:
Follow up ...

Did not see any fuel filter screens BTW?
Thanks
Click to expand...
Nevets,
I'm assuming you have twin HD6 carburetors?
The two fuel filter screens I'm referring to are #42 in the Moss diagram.
 
I'm ruling out ignition issues on the grounds that it would be apparent at start up, not just once warm.

:nonono: No not necessarily a defective coil as has been mentioned will cause the engine to behave this way. Similarly, and a more prevalent failure is a faulty condenser in the conventional point type ignition system.---Fwiw--Keoke
 
Hmmm coil, would have never guessed. Is there a simple way to test for a flaky coil? Other than to replace it?

AUSMHLY, thanks for sending the diagram. I see they are available from Moss.

Thanks again for the assist...
 
Easiest thing to do is replace it. You do have a spare that you keep in the car, don't you? Along with points, condenser, distributor cap, piece of ignition wire, fan belt, hoses, etc., etc.......
 
Bill--

You can test the resistance of your coil with a simple ohm meter--it should read about 33 ohms. Disconnect all wires from the coil while testing.

But the failure mode which Keoke describes occura when the coil gets hot after the engine has been running for a while and I do not know of any way of testing for that other than putting in a substitute and seeing how things turn out. Any 12 volt coil will work and should it turn out that your problem is otherwise carrying a spare is always a good idea.
 
Michael Oritt said:
Bill--

You can test the resistance of your coil with a simple ohm meter--it should read about 33 ohms. Disconnect all wires from the coil while testing.

But the failure mode which Keoke describes occura when the coil gets hot after the engine has been running for a while and I do not know of any way of testing for that other than putting in a substitute and seeing how things turn out. Any 12 volt coil will work and should it turn out that your problem is otherwise carrying a spare is always a good idea.
Click to expand...
I have an very old coil tester that I'm going to do a test on my coil one of these days. I have never seen a coil tester like the one I bought at a garage sale. I'll post the results some day and maybe even a photo of ther tester sooner.
Patrick
 
You can test the resistance of your coil with a simple ohm meter--it should read about 33 ohms. Disconnect all wires from the coil while testing.

Hi Michael did you mean 3.3 Ohms---Keoke-- :smile:
 
But the failure mode which Keoke describes occura when the coil gets hot after the engine has been running for a while and I do not know of any way of testing for that other than putting in a substitute and seeing how things turn out. Any 12 volt coil will work and should it turn out that your problem is otherwise carry a spare.

Yep Patrick :iagree:----Keoke- :thumbsup:
 
I do have a spare coil, points, plugs, condenser, and rotor. I plan to replace all. Hopefully that will solve the problem. If not, then more under the hood entertainment.
Thanks again for the advice.
 
I have an old Snap-On arc-adjusted coil and condensor tester (so old it has no provision for the safety cover over the gap).

I used to use it all the time.
Will heat-soak for test, and will test condensor operation.

A little more set-up to use on the bench rather than on the car, but I've done both.
 
I would check the coil also. As a coil gets older the heat effects it after it warms up and can cause the engine to sputter. I have had this happen several times.
 
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