Posted by Ddd [199.27.128.222] on Saturday, November 12, 2016 at 21:00:16 :
I'm pretty much at a loss where to go next.
I have a 41 Dodge wc12. Fresh Rebuilt 218. Brand new EVERYTHING. I mean everything. Wires. Plugs. Points condenser cap. Fuel pump. Fuel lines. Brand new carb.
Getting an occational "stumbling" or "miss" at high speeds.
Trying to diagnose. Started at the fuel system. Went thru the fuel lines tank to carb.
Replaced the brand new fuel pump with another brand new. Same issues.
Thought maybe my hard fuel line from fuel pump to carb might be too close to the exhaust. Rerouted it slightly further away. No change. (Maybe I need more distance? Boiling the fuel? Causing a vapor lock?)
Put a vacuum gauge to the manifold. Steady even 21 lbs. so maybe indicates besides a great condition motor ( which it is as its rebuilt with less than 100 miles on it) there are no vacuum leaks .
Tried the starter fluid trick to see it any leaks around carb base or manifolds. Nothing.its all right as far as I can tell.
Running points and condenser. Could these cause an occational miss at high speed IF defective? Point gap or dirty points do this? Haven't checked them since I installing when the engine was installed last summer.
So after all this and still same issues, this crossed my mind as I pulled in Tonight. Getting dark. No time for more trials. What about a really tight gas tank filler cap causing a vacuum to the tank, ultimately starving the engine for a split second?
Then recovering quickly?
Anyone ever experienced thiS sort of thing with vacuum to the tank due to gas cap creating this condition?
I am at a Loss where to turn next. Tried everything from rebuilding the brand new carb to every adjustment I thought would work to the carb and to the timing. Nothing changes the stumbling .
Maybe I'm looking at the wrong area. I'm assuming it's fuel but could it be electrical related? An occational ground or something I'm missing? I checked my new wires I don't see any arching at night. Any advice or experience related to this would be grateful if shared!
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