Farmall H Lack of Power after Rebuild

apz*jr · Oct 9, 2016

I rebuilt the engine on my H last summer and have had an ongoing issue with lack of power when I take it tractor pulling. The head was decked & rebuilt, oversize stepped head pistons are about the only major modifications. Ever since then some pulls it runs great and others it lacks power. Things I have tried so far:

-Adjust the governor
-Went to distributor instead of mag (even when I had the mag it lacked power)
-Installed a hot coil & plugs
-Tried a larger carburetor (just smoked a lot with it, then took it off shortly after)
-Checked valves
-Checked timing

First thing I am going to do when I get it back out of the barn is check compression but it fires right up and sounds good when it runs, just lacking overall power. Any ideas of where to start would be great.

Thanks!

kevinj54 · Oct 9, 2016

(quoted from post at 15:58:19 10/09/16) I rebuilt the engine on my H last summer

Any ideas of where to start would be great.

Thanks!

Put it on a dyno so you know where you are.

Brownie450 · Oct 9, 2016

Gasoline different than before on bad pulls??

Solid plug wires??

Condenser maybe causing trouble/ acting up at different times?

Hard to pinpoint intermittent problem.
Jim

apz*jr · Oct 9, 2016

I have been running the same fuel. I replaced the plug wires with brand new ones too.

For example, when I went to the same track twice this year- the first time it ran good no issues, the second time I ran out of power right away.

PretendFarmer · Oct 10, 2016

What octane are you running? How many turns out on the main jet? Do you have the timing too far advanced? Some people think that running advanced timing and high octane gas on relatively low compression motor is helping. Unless your running really high compression I would retard the timing a little bit and run no higher than 89 octane.

rustred · Oct 10, 2016

things need to be set to factory settings... then tweeked from there.your checking and adjusting but not saying what timing, points,plugs, has correct wires? distributer advance,need to make sure all ignition parts are good. valves, carb , or governor is set at, or if even running at rated rpm. a compression check is always first on the list.

D beatty · Oct 10, 2016

If you put an over haul kit with larger pistons didn't it come with a kit for carb and parts for dist for the kit. They also give you directions on what to reset timing for kit. I have never redid an H but had done an M and had to advance timing 22 degrees.

rhtx55 · Oct 10, 2016

Too many variables. As stated above, using a dyno to dial in the carb & timing advance. That will be the only way to get it to pull correctly under a full load. You will also then know what HP you are actually putting out. There are many "tricks" to getting more ponies, but this would be your absolute starting point.

David G · Oct 10, 2016

A lower compression engine can run total advance around 30, a higher compression will be better around 22 to protect pistons.

Farmall H Lack of Power after Rebuild

apz*jr

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kevinj54

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Brownie450

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apz*jr

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PretendFarmer

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rustred

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D beatty

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rhtx55

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David G

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