zeinith carb F20

Hello,
I just finished restoring my 1935 F20 and had to have the magneto redone. after getting it back I had problems starting it. the guy who did the work on the mag. said to make sure that when I remove the plug on the bottom of the carb that fuel runs out for a while. now I rebuilt the carb and it had specs for the float level. so I m not sure if he is giving me correct info or not. I removed the bowl and the fuel was to the top of the bowl. I would guess that was correct. I wanted to see if anyone else did this.
Any help would be greatly appreciated.

Thanks
Jim

If you set the float to the specs, and it doesn't leak, you should be OK.

I think his reference on the bowl plug is to verify that after it emptys, that there is still a strong flow of gas to the carb. A weak flow would indicate blockage in the tube or at the base of the gas tank. Crap in the tank can impeed flow of gas to the carb. Impeeded flow would most likely result in a tractor that will start, but begin to fail a few minutes into running, and/or under a load.

After cranking and it doesn't start, are your plugs dry or wet? If dry, you are not getting gas. If wet, something's a-muck with your spark.

Thanks I cant check that at the moment but I thought they were wet. I even put gas in the cyl. an no start. that"s not saying I could have two problems but it has been a hard starter from day one. all involving spark. I am waiting on an exchanged magneto and once I get it I will recheck the fuel.
Thanks for the help

What plugs are you using? Autolite 3077 are a long reach plug that makes these old girls purr pretty easily.

You said you just finished restoring it. Did you
paint it? If so, then the mag might not be
grounded well and thus weak or no spark even
thought the mag is hot. You can use a continuity
tester to make sure the mag is grounded.

What I do is wire brush out one of the tapped
holes in the mag and make sure it is corrosion
free, wire bush and shine up the threads and
inside of the head/lock washer of the bolt, then
scrape off the paint where the head/lock washer
contacts the mag bracket. I coat with dielectric
grease and tighten down. Always works.

Yes, One problem at a time. Don't worry about fuel until you have spark. I use starting fluid. If it will fire and run with starting fluid you have a fuel problem If it won't you have a spark problem.

Cowman is right on. one problem at a time. you very well could have 2 issues, but if there is good, hot, spark at the plugs, then you can move on. At times, these old girls can seem to be possessed by demons............but they aren't. One step at a time.

Spark, fuel, and timing: they will start and start easily.

1.) check for good spark, make sure wires are copper core and good contact. Make sure mag has good ground. Make sure points are clean and set right.
2.) fuel - make sure primer cups are shut or plugged. make sure carb is clean and good fuel flow. Ether is an option as well as Cowman states.
3.) Make sure your timing is set right. Not a hard thing to do. #1 on TDC on compression stroke. Mag impulse should trip at that point, not before, not after, but at TDC.

Unless there is something mechanically wrong (stuck valves, sheared key on cam or governor gear, leaky head gasket, wrong valve lash), it will start and run.

PS I once bought a mag from a guy who said he rebuilt it. Well, there were new parts: points, condenser, coil, and the inside was clean. However, he had the internal timing off by 10 teeth on the distributor plate. took me 2 days to diag that, and a dis-assembly of the mag. Not saying that is your problem, but also something to consider.

Harbor Freight has a neat device you put on a spark plug that lights when it fires. That could help determine if the mag is firing.

Also, use the "Twisted Belt" method to start it and you can diagnose your possible solutions while the engine is turning.