Cure for vapor lock?

TDR

Well-known member
I'm running a basically stock 200-6 in a '66 Mustang. It's been fully rebuilt, everything is nice & fresh, and it runs great. However, in hot weather, and upon restarting while still hot, it acts up in a way that I would relate to old-fashioned vapor lock.

The temp gauge does not show it as hot, but I haven't done a temperature measurement to determine precisely at what temp it is running.

My question is, to help correct this situation, would it be beneficial to disable the stock "carb-heater" arrangements - the heater hose which routed through the carb base, and the "plenum" tube, which goes from the manifold to the choke body on the carb?

Both items are primarily redundant for my car and are mainly for looks, because I don't drive it in cold weather, plus I'm running a manual choke.

Please give me some ideas, guys. I want to correct this nagging problem, but would sure appreciate some experienced advice on how to do so. Thanks.

Ted G.
Salem, Ohio
 
Contrary to popular belief, the carb heater system is actually more of a steady-state temperature control device. I should know...I live in south Texas and had serious carb fuel-boiling issues until I hooked it up. Now, the carb doesn't so much as hiccup.

That said, it sounds like you need to check your carb float height. From what I understand, that's generally the REAL culprit...
 
I am setting in East Texas, 101 degrees on the drive home, temp guage running 3/4 of the way up. Hot starts are just fine.

Try setting the float and you might find a happy place. I don't know how much the elevation will affect it, but that is where I would start.
 
If you can avoid alcohols in the fuel (not possible in many areas now days) it should give you some more headroom.

One of my cars I ended up putting an electric fan on the front of the radiator hooked up to a mechanical bathroom timer, just gave it a wind to about 10 minutes when I parked and 99% of the time thats all it took to keep it happy. Now running EFI even happier.
 
An electric fuel pump will also cure it and you can leave the float level a tad low so it doesn't boil over after stopping and flood the engine.
Works for me.
 
This is probably redundant info. at this point but I would have to agree with the input you have been getting so far. I have a 67 Mustang, 200 hooked up just as you described and I'm pretty sure it was 110 or better here today and I have had no heat related starting problems. Try adjusting the carb float as suggested.... sounds like a good bet to me.
 
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