Farmall H starts to miss after warmed up

slydog · Sep 29, 2008

I have a Farmall H that starts real nice and hits on all 4 cylinders when it is cold. As soon as it gets warmed up it starts to miss on 1 cylinder and sometimes 2 cylinders. Example: I started it up and drove about a mile in 5th gear and it ran perfect. Then it would start to miss once in awhile and then steadily got worse the farther I went to a point it wouldn't hardly pull itself in 5th gear. I checked the gas at the carb and it is getting plenty of gas. I am leaning toward an electrical problem. It has a magneto. I put new points in it 2 years ago. Could it need points again or could it possibly be the condensor? Any ideas would be most helpful. Thanks.

John T · Sep 29, 2008

If its NOT fuel related, and it gets worse as she gets warm, Id suspect the points (clean n buff n regap or replace if burned bad or pitted) then the Condensor (easy n cheap thing to try) then finally the coil as its more expensive n harder to change then points or condensor. How are the plugs?? If oiled up or real black you may wanna try a set of fresh and a bit hotter plugs also.......

If its NOT fuel or Ignition, you may wanna check the valve lash

John T

rustyfarmall · Sep 29, 2008

Pull the valve cover and check the clearance gap. Sounds to me like the gap is too small and when the engine gets warmed up, everything expands, and the gap pretty much goes away which prevents those valves from closing completely. If that doesn't cure it, you might have some issues with the manifold to engine gaskets, or even the carb to manifold gasket, but I'm puttin' my money on the valves right now.

teddy52food · Sep 29, 2008

When you changed the points, did you put a new condenser in too? Check the points and if they have a pit on one side and a peak built up on the other, the condenser is bad. I would put in both and if that doesn't help, I would change the coil next. If the valve lash is not enough, you should notice the exaust change sounds as it gets hot.

El Toro · Sep 29, 2008

I would check that valve lash as Rusty suggested. Hal

Bob Kerr · Sep 29, 2008

You might look and see if there is an oily film inside the cap also. Mine was acting up because of that a couple weeks ago. Cleaned with carb cleaner inside cap and off rotor and it is all good now. also make sure it isn't running too rich. It will run good cold since not all the gas vaporizes cold but warms up and the fuel mixture gets too rich (all the gas vaporizes). If that isn't it, I am with the others on the cond/coil.

RJ-Wi. · Sep 29, 2008

I hope it isn't this but it could also be a cracked head. When it gets warmed up the crack opens up enough to cause the engine to miss. I've ran into this alot on the M's and supers. They of course have higher compression and have been worked harder for the most part. These ol tractors have been heated up and cooled down so many times in their life that the metal has reached its limit and causes cracks in the heads.

slydog · Sep 29, 2008

I did not put a new condensor in the last time I put points in. The spark plugs are new autolites. I think I will try new points and a new condensor first. What is the correct gap for the points? Where can I get points and a condensor for a reasonable price?

El Toro · Sep 29, 2008

Set your valve adjustment to .020" cold. Hal

jonnny2006 · Sep 30, 2008

sounds like an intake leake .... check and ake sue al the bolts are nice and tight and when the engine is cold you can take a hose over the intake manifold and see if you get any white steam smoke, thats what was wrong with my 43 now she runs like new

Farmall H starts to miss after warmed up

slydog

Member

John T

Well-known Member

rustyfarmall

Well-known Member

teddy52food

Well-known Member

El Toro

Well-known Member

Bob Kerr

Member

RJ-Wi.

New User

slydog

Member

El Toro

Well-known Member

jonnny2006

Member

Similar threads