[Farmall] 1951 Cub won't start when very hot

[Tractorman453657 at aol.com]

>From what you have said it doesn't sound like a spark problem  especially 
with the electronic ignition. All though if you aren't using the  proper coil 
with the petronix ignition you may be having a brake down problem  with the 
coil. You must use a coil that is compatible with the  petronix  ignition. 
The reason I say that is because I tried  to use a  regular coil. I had 
problems. Without more information on the engine  such as  has it been 
overhauled? If so then what was done? If not, has  there been regular maintenance ?  
>From what I gather  your over  filling the radiator, leave it down about 1 
1/2 inch from the top. The coolant  needs expansion room.   The first ting 
that comes to my mind when you  say it wont start after running a while is the 
engine valves. If they are out of  adjustment ( too tight)  the valves 
might not be closing when hot causing  the problem. I would make sure the valves 
are adjusted properly of you haven't  already.
 
 
In a message dated 8/30/2010 1:25:57 P.M. Eastern Daylight Time,  
DBigdog at columbus.rr.com writes:

Jim,
You have covered all the common causes for  non-starting in the cub 
engine.  Coil failure is most common and a  new coil could still fail. 
However, before throwing parts at it, check for  presence of a good spark 
when trying to start it hot.  If you still  have a good hot spark then 
ignition is not an issue.  If your engine  is getting hot enough to boil 
the 
coolant it is possible that you have  valves sticking when the block is 
that 
hot.  A compression test when  hot should tell you if that is the case or 
not.
If you  can start by verifying spark when hot we can decide which 
direction to  head in troubleshooting.
I might also suggest that you check out  www.farmallcub.com as there is 
lots 
of cub information available there as  well as a very active online forum.

BD
----- Original Message -----  
From: jimbon88 at aol.com
To: farmall at lists.antique-tractor.com
Sent:  Monday, August 30, 2010 12:44 PM
Subject: [Farmall] 1951 Cub won't start  when very hot




Hi Folks,

I've been lurking on this  list for a while to learn about my Cub but have 
never written in.   Now I have a problem that I can't solve and would like 
to know if  anyone has any suggestions.   My Cub starts right up when it is 
 
cold or hot, but after running it so hard that the coolant is boiling in  
the 
radiator and it is VERY hot, it won't start.   It turns over  just fine so 
I 
don't think it's the starter.   I installed a new  coil with no change. 
Then I thought it was a fuel vaporization problem,  but I can smell gas at 
the exhaust pipe and choking it makes no  difference.  I have a pertronix 
ignition in it now, but it acts the  same as when I had the points ignition 
system were in it.    If  I let the engine cool down for an hour, it starts 
right up as if nothing  was wrong.   Does anyone have any other thoughts as 
to what  might be causing this no-start condition?   Thanks for the  help.

Jim  Gearhart




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