The Stovebolt Site Forums The Shop Area Engine Shop No consistency

Hi guys. Long time no see.

I've been playing around with the Blue Funk ('51 3100 with a '57 235, carter carb) and it seems to have no consistency in its symptoms of running poorly. It began being difficult to start, so I played with the timing, air, and throttle settings. Then, I found the mounting nuts were a little loose, tightened them down, and adjusted the air mix. All of a sudden, it ran perfectly! Cruised at 40-45 mph and would hit 50 mph with little exertion! I was in 7th heaven! Then, later in the same day, it began being hard to start with out tromping the gas pedal and hesitating a bit in high rpm's. When the engine warms up a bit and will idle without giving it a little throttle, it idles funny, like consistently timed waves of high and low rpm's.

It starts easier sometimes than others, and runs better sometimes than others without rhyme, reason, or intervention.

What do you think?

Oh- BTW: Recently tuned up with new points, plugs, condenser, etc.

Could be a long shot, but do you have a good (very good) battery to frame connection and engine to ground connection? Sounds electrical to me...

Check the distributor and make sure the mechanical advance weights are not hanging up and that the vacuum advance is working every time it's suppose to.

Just to be different, I’m going another direction. Trash in the gas tank covering the outlet, partially sometimes, fully others. Sloshing around starving the carburetor until it moves off the outlet. Just an idea based on practical experience. 🛠

Also check for water in the gas.
And that the cap is vented, if when it acts up remove the gas cap, if it hisses loudly it’s not letting air in to replace the gas that is used.

Hard restarting of a hot/warmed up stovebolt engine is not an unusual thing. Built up heat reeks havoc to the fuel in a carbs float bowl once it transfers from the hot manifold to the carb. GM and pretty much all manuf's put carb insulators on to try to prevent the over-rich heat transfer condition that occurs all frequently.
1st thing I'd do is make sure theres an insulator installed then check the float settings. If your carb is a Rochester B model check the power piston for free movement. If it's stuck it's generally in the rich condition. Course it'll give overly rich symptoms at all times.
All that said, which may be alot of hot air, LOL., try the following.

On your next hot restart, while cranking slowly depress the gas peddle all the way to the floor so the throttle plate is fully open, if it doesn't start slowly return the gas peddle back to it's idle position. If the engine is in an overly rich condition it should start somewhere in the peddle return. What you're doing is finding the sweet spot where the air/fuel passing through the carb is the right mixture.
My old 216 would restart during the slow depressing phase but every now and then it wouldn't start until the releasing phase.

Additional causes to making an overly rich warm/hot engine restart is carb set too rich, choke not fully open, heat flapper valve stuck in "open" position, float set too high, someone put in a larger main jet, restricted air filter, using an electric fuel pump with too high a pressure, fouled plugs, timing too retarded, points set incorrectly, valves not properly adjusted to name a few.

Read your plugs, if they're black and sooty the engin eis running too rich.
Good luck
Dave