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Runs great then....

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Guinn

Guinn

Jedi Warrior
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My 78B runs great, then after several miles it starts stuttering and, unless I nurse it along slowly, it will die. After it sits for a few minutes it will re-start and run fine again, then same thing over again. I suspect a plugged vent but I got the car with the EPA stuff removed and the tank vent tube by-passing the round can under the RR fender.

Anyone got ideas other than a plugged vent line? How can I check the vent line so I can tell if this is the problem?

Guinn

Tony, please see your PM.

Guinn
 
If you were "down here" i'd say: "MUD WASPS!"

A plugged CAT converter if it wasn't removed with the rest of the 'stuff'. Tank vent line and cannister? Have you tried running with the fuel cap off or loose?

The vent at/for the carb float bowl is the most likely suspect. You'll need to remove the line at the carb and blow air thru it and check to see there's no obstruction at the carb body too.
 
Yes, it does sound like fuel starvation. That is why I pulled the filter (and crushed the old, brittle brake fluid reservoir at the same time) and asked about the venting. While I am sure the problem is due to a plugged vent somewhere, I don't know ALL the places to look.

No, I don't have a cat. Pulled by the PO. I do have a DVG carb. Fuel flow at the filter is super.

Thanks for the ideas,

Guinn
 
Hmmm...DGV. Diff'rent set of rules then. Try the "loose" cap experiment, and don't discount that the fuel pump could be getting hot and fail to maintain constant volume after some length of run-time. What pump do you have and do you know its age?
 
Beats me, Doc. I never have had problems with the pump. Hopefully not now, either.

I can't safely run the car until Tony comes up with a new brake fluid reservoir for me as I (stupidly) leaned my elbow on the cap while trying to wrestle the fuel filter from the fuel line. Crushed the cap into the reservoir.

Don't happen to have a spare reservoir for a 78, do you?

Guinn
 
My "collection" is all pre-'68 now. But I'll look thru my "lucky bucket" in a bit.
 
Guinn, I had a similar problem a while back. It was a cracked fuel supply line from the tank to the pump, the one with the braided shield. It would start and run, (drive), for about ten minutes and then quit. It would start right up after 30 seconds, run ten minutes and quit again. The pump was partially sucking air. New line, problem solved!
happy0034-1.gif
 
Guinn said:
Beats me, Doc. I never have had problems with the pump. Hopefully not now, either.

I can't safely run the car until Tony comes up with a new brake fluid reservoir for me as I (stupidly) leaned my elbow on the cap while trying to wrestle the fuel filter from the fuel line. Crushed the cap into the reservoir.

Don't happen to have a spare reservoir for a 78, do you?

Guinn
Click to expand...

I saw one one ebay on a used MC for $10
 
Ditto the fuel delivery idea as it is probably the culprit, but don't rule out a bad coil.

When they decide to retire they will over heat and when hot enough open the internal primary winding. I don't know how long your non-start condition persists but if you mount a known good coil next to yours temporarily you might be able to jump out and swap wires around fast enough to produce an instant cure and pin point it to the bad coil.

Checking for an open when the coil is cool and operational is futile.

Jack
 
Just want to thank Tony for the quick job he did finding me a used - but good condition - brake fluid reservoir.

I should have the car back on the road in a few days, if we ever get two sunny days in a row!

Guinn
 
If you are running the Stromberg, the problem is almost certainly the vent line from the carb to the canister. The next time is hesitates, pull the tubing off the canister to see if the problem goes away.

Do you have the heat shield in place? If not, you might want to consider installing one, as excess heat around the carb can also cause the problem you are having.
 
Just to add to my my earlier post; if the removing the vent line does appear to fix the problem, you will need to dismantle the canister, clean it thoroughly, and replace the charcoal (pet stores carry it) and that should guarantee a free-breathing system.

The reason for the heat shield is to prevent vapor locks.
 
Thanks, Barry. I do have a Weber Downdraft, not a Stromberg. I put in a heatdshield as soon as I saw that the gas line ran directly over - and close to - the exhaust manifold. I believe my problem is in the venting system but will not know for sure until the weather lets me run around a bit again.

Guinn
 
Finally got the brake fluid reservoir in and found it had two small hairline cracks in the upper part of the shell. Hard to see but probably my fault.It came in the mail well padded.
Yesterday I had a chance to try some fibreglas stuff I had sitting around. I wasn't about to take that sucker out again (it had a frozen mounting bolt to start with), so did the fiberglassing in situ. Two coats (layers) and now it is really armored! Brakes work and life is a joy!

Guinn
 
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