need guidence

Sat Jun 19, 2004 11:50 pm

Hello Cubaholics
Long time no speak. My '57 lo-boys been running like a swiss watch until recently....and I don't know where to start to troubleshoot the problem. Starts great when cold, and will run great till I shut it off, but will not restart until engine cools. My first thought was bad coil--replaced it-- no help. Ammeter usually shows aprox. 5 amps running with lights off.....around 0 with lights on. Now.....for the past week, ammeter showing -5 lights off, -10 lights on. What would be the first step in finding the offending componet? This not starting when hot has been going on for some time now....before my charging problem....or could my ammeter have been lying and these problems be connected? Where do I start, and what do I look for. I'm lost

Sun Jun 20, 2004 7:54 am

Lets start with the charging system.
Since the charging system just started acting up I would start with
checking all wire connectionsalso ck. for proper voltage at the terminals.
From there check the points in the regulator. You might also take the band off of the gen. & check to see if the brushes are worn out.

As for the hard restart when hot even when charging system was working 2 things come to mind 1condser breaking down 2 vapor lock at the carb.
There is 1 more thing are you using the starter to try a restart or are you hand cranking?

Sun Jun 20, 2004 8:52 am

Thanks for your reply Dale,
I posed the question about vapor lock some time ago and was told it was impossible to get vapor lock on a gravity flow, updraft system. Is there a quick way to isolate a condenser problem? I have the cheap & cheesy IH repair manual but it leaves a lot to be desired. If vapor lock is can it be cured? Starting with battery.
Last edited by splicer on Sun Jun 20, 2004 9:10 am, edited 1 time in total.

Sun Jun 20, 2004 9:02 am

If you have a Zenith carb, you can check or relieve the vapor lock by removing the drain plug at the rear when hot. Another thing to check woud be the bolts holding the manifold. if they are loose, or the gasket bad you could be getting enough air leak when hot to make starting very dificult.

Sun Jun 20, 2004 9:21 am

Thanks John,
This may sound ignorant, but what do I look for in a vapor lock condition when I pull the plug? I haven't had any experience with vapor locking.It is a zenith carb about 1 year old. Can I spray starting fluid around manifold connection to check for air leaks? If I do find a vapor lock is it solved?

Sun Jun 20, 2004 9:58 am

I would tend to think the valves need some adjusting

Sun Jun 20, 2004 10:08 am

Thanks for your input Jim,
What makes you thimk that? Sounds like we're missing something your not. Please explain. To be honest.....the valves haven't been adjusted since I've owned it......2 years.

Sun Jun 20, 2004 11:19 am


As Jim said it could be that that the valves are too tight. When the tractor is hot the valves may not be closing completely due to expansion.

Check the simple things first. The plug on the carb would be a good place to start. When the tractor won't start remove the plug and make sure there is good fuel flow.

Sun Jun 20, 2004 12:26 pm

OK Neighbors....just got home from church, got my work duds on.....gonna get busy. With all the input from you "Cub Masters" I will start attacking the charging problem first. Found the link to the charging problem flow chart and this will help me alot. I do appreciate all your advice for I'm not near the cub mechanic you guys are. Will post my findings. Happy Fathers Day to all you dads out there, speaking as a son I can tell you fathers our lives would be sorely different had it not been for the wisdom, encouragement, and patience of our Dads....oh yeah, and the butt whippings (probably the most important)

Sun Jun 20, 2004 12:39 pm


Check the Blue Ribbon Service Manuals as well as the Best of H.L. Chauvin and the other Cub Info including the FAQ's. They will help. Click the manual link below.

PS - Ifn I can do it :shock: :roll: :? - so can you :!: :D

Sun Jun 20, 2004 1:37 pm

Splicer, Do NOT spray starting fluid around the gasket to check for a leak. if it ignites things will get real unpleasant.