1943 H missing on #2 cylinder

Andy Motteberg · May 25, 2008

Hi all,
I have a 1943 Farmall H that I restored September 2007. It has always started and ran very good, but a couple days ago, it got a problem where it misses on the #2 cylinder. If I pull out the #2 plug wire while it is running, it makes no difference in the way it runs, so I know it is #2. There is spark at the #2 plug, but it still is missing on that cylinder. The other cylinders are not "missing". I removed the plugs and checked them out, they look very good, the were replaced a couple months ago, they are Autolite 3116 plugs. It has new copper core wires too. The mag has a good blue spark and the cap, points, condenser and rotor were replaced in September 2007. I did a compression test only on #2 cylinder and I've got about 65 in there which I think it about right for a all-fuel engine. My Dad said maybe it was a bad valve. What do you think? What else should I check? I sure hate to take the engine all apart again, but it is running very poor when only firing on 3 cylinders. It was running perfect before this happened. Any help would be appreciated! Thanks, Andy.

Mike L · May 25, 2008

I would try switching the # 2 cyl plug with # 3 cyl to see if it still has a miss in the # 2 cyl.
Ive had plugs that look good but still be bad.
try this before you tear the motor down.

Anonymous-0 · May 25, 2008

Andy, that's exactly what my '45 did last month. Always ran perfect and all of a sudden a miss. Wouldn't rev up for me either. I pulled the valve cover off and sure enough one of the rocker arms came off the pushrod so I had one valve not opening. Slipped it back on and it runs perfect. When I did the compression test it had good compression too.

old · May 25, 2008

Sorry but I HATE the term restore. If you truely did a restore then you have a new engine right??? As in you rebuilt it right?? Ok I'll stop[ ranting. Check the cap and see if maybe its bad. You do have copper core wires right?? Try a hotter set of plugs and see if that helps

Anonymous-0 · May 25, 2008

Andy,
That tractor is well over 50 years old, if it was "restored" 9 months ago, you can't have killed it yet; Check Simple things first; valve adjustment, a stuck valve or bent push rod would give good compression readings but still not run. Try swapping a good running plug with #2 and see if the bad cylinder follows the swap, your eyes are better than mine if you can tell a good plug by looking at it,many will fire fine in the open but not when under compression.

Andy Motteberg · May 25, 2008

Thanks Scott, I'll take off the valve cover tommorrow and check out the rocker arms/push rods.

Andy.

Andy Motteberg · May 25, 2008

Thanks, I had tried the plug from one of our other H's and it did not cure the problem.

Andy.

Andy Motteberg · May 25, 2008

The cap was replaced and is good. Yes, I do use copper core plug wires like I said in my post.

Thanks,
Andy.

Andy Motteberg · May 25, 2008

Thanks.

edward_m · May 26, 2008

Andy, hate to bring this example up, but I have a '40 H that ran like a top until last year, when it kept missing on a cylinder. Tried everything in electrical, tried adjusting the valves, just could not get it to run right.

Then followed some advice, and found that the intake valve guide was worn and leaking oil. Intake stroke sucked it in like a pump. Compression test wouldn't show any problem, 'cause it sealed on the upstroke just fine. Yet fouled the plug so fast you wouldn't believe it. I changed the head with another, and the problem vanished.

I HOPE it's something else, but when you check the valve train, see if any of the intake valves have any side to side play. They should be tight. If you find play, you need a valve guide job, or a new head.

John M · May 26, 2008

You said you swapped the plugs, but what about that wire? (BTW, I beleive you can restore a tractor and not touch anything in the engine, or transmission.)

El Toro · May 26, 2008

Check the valves on that cylinder. Hal

JT · May 26, 2008

Get a can of WD40, or carb cleaner, with tractor running, spray around the intake area. Might have an intake gasket leaking.
Jim

Red Mist · May 26, 2008

This is amazing; now, my super H has just today started missing on one cylinder. Must be something going around contagious to members of the "H" family. Guess I'll check compression, pull the valve cover and go from there.... : mike x

Andy Motteberg · May 26, 2008

Good luck with yours Mike.

Andy Motteberg · May 26, 2008

Thanks

Andy Motteberg · May 26, 2008

Yes, I've tried another wire off the running 300 and did not cure the problem. Thanks.

Andy Motteberg · May 26, 2008

Thanks.

Andy Motteberg · May 26, 2008

They look good from under the valve cover.

dave guest · May 27, 2008

Andy if you crimped plug wires, take continuity tester or meter and make sure you didn't lose connection. Copper should read practically zero ohms. Compare others if in doubt. New wires can be bad. Even factory crimps.

Andy Motteberg · May 29, 2008

Thanks, I put in new D18Y Champion plugs today and it runs right again.

1943 H missing on #2 cylinder

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