A will not run nice

R

Ron McIntyre

Senior Member
I asked a club member to check out this problem Plugs regaped. Timing checked . Compression checked. Carburetor rebuilt and tested on his car . Runs rough and hesitates on acceleration while in the garage. The 2 manifolds were taken to a machine shop. 90 thou was removed. Looked nice. I am ata loss to what is wrong. Please help.
 
Good morning Ron.

A simple way to rule out a couple of things is to swap out one at a time your distributor and your carburetor with known good ones from one of your fellow club members.
 
A few things to check: Make sure the polarity on your coil is correct. Check the gap between the distributor rotor and the pin in the housing. Spec is 0.025 I believe but the smallest gap without hitting works best (bend arm to adjust). Check the jets for proper hole size (drill out or buy flow checked jets) but you said the carburetor was rebuilt and tested. I assume you have fresh gasoline but if not try that. Even though the manifolds were machined check carefully for leaks (a small hose held to your ear can be used or unlit propane torch). I assume you have played with the advance lever and GAV. You can buy a clear distributor cap if you want to look at the sparks when the engine is running. Check the points and condensor. Check the entire electrical system for loose or corroded connections.
 
Last edited:
Might also check the valve lash. Had the same presentation which turned out to be two valves with insufficient clearance. Let us know the fix.
 
1. Carburetor float level it could be too low. Remove washers under shut off valve or carefully adjust float end stop. GAV should be 1/4 to 1/2 turn open.
2. Replace the condenser even if it is new.
3. Check intake manifold gaskets for proper alignment. With engine cold retorque the manifold nuts to 50ft-#'s
 
I had a Model T that ran like that, turned out that the camshaft was badly worn. A reground camshaft cured it.
 
If you are confident about your carb, and fuel it has to be ingnition related. I had an intermitent issue once when my cable going into the distributor was in too tight. Turn the cable coming from the ignition switch to the distributor back 3/4 turn and see what happens. You can always turn it back. Other than that the condensor or the wire under the plate of the dist are always trouble spots.
 
Hi. Changed the carb nos c4 Plugs checked compression says 60 on all 4 gas flow is good points checked ok. At idle is fair and when accelerate misses. Seems ignition issue. Or ?
 
Tighten manifold nuts 25 - 30# incrementally rt to lt or lt to rt until you get to a max of 30# on each nut.
 
Ron, I suggest that you and your friend review post #3. It is a worthy list of checks. Your carb substitution may account for the jet size item, but it would help to methodically perform the list of checks Neil has written and then come back with what you found on each one and by what method you tested it. There are a couple more easy items that I or others may suggest after receiving your followup.

FWIW, The last item in his list is a common failure point. "loose, dirty or corroded connections" can reduce voltage and thus amperage flow in the ignition system causing weak or intermittent sparks. Low voltage/amperage may not adequately saturate the two internal coils and thus secondary circuit voltage is missing or weak, especially as load or rpms increase. (And now I'm espousing things way above my pay grade!)

If you or your friend or another club member have the Les Andrews (blue) book "Diagnosis and Troubleshooting" chapter 2 page 32 has a quick and easy test to help you determine if there are issues in the wiring. Other pages have easy tests for battery grounds and cables.

I hope this helps you.
 
Last edited:
I was going to suggest you check for a bent timing pin,I've found a couple of them lately. People pry against them sometimes.
You can use the A timing pin,here's how. Install pin,mark a spot on the crank pully. (Tdc is 0)Mark another spot on the pully 7/8" away Clockwise. Now turn the crank counter clockwise to the new mark.
This will set you at (9 degrees Btdc) Now set your timing.
 
Mine was doing the same a couple weeks ago, I tried a another carb and it ran exactly the same. I could pull the choke on mine and it would run better but go back to same after I let off of choke. I took it for a spin just to see if it would straighten out and it did. I have no idea what the problem was as I had changed points and condenser with new and it still ran the same. It may have been wiring connections also I haven’t ran a ground strap to the transmission yet either. Mine did start missing as I pulled a steep hill on the way back to shop but cleared up as soon as I got past the pull. These old cars are simple but can make you want to pull your hair out. I guess that’s part of the fun and learning exactly how things work. I’m tired of some problem all the time it seems but I’m not stopping, I love driving it and understanding it more. Good luck with yours and make sure you let us know what the problem is.
 
CT Jack said:
1. Carburetor float level it could be too low. Remove washers under shut off valve or carefully adjust float end stop. GAV should be 1/4 to 1/2 turn open.
2. Replace the condenser even if it is new.
3. Check intake manifold gaskets for proper alignment. With engine cold retorque the manifold nuts to 50ft-#'s
Click to expand...

50 lbs is too much. 25-35 lbs is good.
 
History: Fully pulling out the choke with full throttle is an old trick to clear a clogged main jet or other passages in the carburetor. It may be that partial choke did the same thing.
 
Last edited:
You must log in or register to reply here.
Back
Top