Farmall A Engine is Spinning Backwards

[FarmallA1943Eh]

Hey all, first post here.

Just finished up a not restoration but freshening up of my grandfather's 1943 farmall A, and I'm confused because the engine started and ran backwards

I started the engine with the crank, cranking it clockwise as that's the only way the spiral will let me (unless I'm crazy), the thing started and ran. Me being super excited to hear the thing run hopped on, put it in reverse to back out and the tractor drove forward. Put it in any forward gear, tractor reversed.

I tried searching up a bit on this, but im wondering if anyone has encountered this before, most posts revolve around the engine dieseling for a short time after shutting off, but not like this.

Thing hasn't run in 8 years, I did pull the distributor cap off and rebuilt magneto, but im pretty sure I never pulled the distributor itself out completely(maybe I'm wrong, It was a while back I did that).

Any ideas of where to start?

Thanks
Ben

 

[tractorsam]

I think youll find the engine is running just fine, I assume it built oil pressure? It really can only run one way (for any amount of time) otherwise the exhaust would come out the carburetor.

More likely someone had the transmission apart and the differential is in backwards. That would give you 4 reverse gears and one forward.

 

[used red MN]

Hello Ben welcome to YT! You are a month and 4 days late for April fools, maybe you get an early start on Cinco de Mayo!! ; > ) Did you have the tractor completely tore down rear gear train and all? If so it appears you did it without the proper manuals. Now not 100 percent sure if it can be done on that tractor but what it sounds like you did was installed the rear differential ring gear on the wrong side of the pinion gear. That will effectively make reverse a forward gear and the forward gear reverse gears. A gas engine cannot run backwards because the fuel air mixture would have to come in through the exhaust valves. This can and does occasionally happen to diesel engines that inject the fuel directly into the cylinder. When this happens the engine will have no oil pressure because the oil pump cannot pump oil into the engine when running backwards.

Edit: I see Sam beat me to it, I got interrupted because we were ordering dinner from the local Mexican restaurant to celebrate Cinco de Mayo! Not sure which side the gear should go on, the diagram is not specific enough to tell. Not that familiar with the Cub, A, B and C my experience is with the H model and on up.

CNHI Farmall A Rear Differential diagram.


This post was edited by used red MN on 05/05/2023 at 05:58 pm.

 

[FarmallA1943Eh]

Well ill have to eat a big slice of humble pie. I never even considered it a possibility that the rear diff could go in and function properly both ways.
You guys are 100% right. Just went through the pictures of when I rebuild the transmission and sure enough the diff is in backwards

I can't even explain how much of an idiot I feel like.

That's a lot of hours wasted, I guess the only bright side is all the bolts are new and clean and ill never do that again

 

[rustred]

i cant see that . first that engine rotation is counter clockwise. engine rotation is from sitting in the seat, or standing behind the engine. now we have that straight. next if it started it wound be spinning the crank like a windmill, probably hurt you real bad. next is it a magneto system, or the distributor that needs a battery? your not clear on that. next the oil in the air cleaner would be all blown out, and even the oil pump would be turning backwards. the distributor would be turning backwards also. i actually dont think it would actually run backwards that you could drive it. which gears did you use? do u have the gear shift pattern? reverse is top left. rest are forward. i have seen them diesel , but that is not turning backwards,.. that is running without a spark in the normal direction.the only tractor i have seen run backwards is the john deere 720 and it happened to me. also at our show there was a guy with a lantz bulldog and he made it run backwards by almost stopping it and then let it rock a few times them it was running backwards. i was standing right beside it when he did this. and.. if you have this tractor timed correctly it will not kickback either. so confirm the gears u used would be my first thing to verify. as i said no way for the crank to become disconnected if it started in reverse direction.

 

[rustred]

there u go that will do it, now we have the rest of the story.

 

[used red MN]

Well rust this time your practice of not reading others post first because no one else could possibly answer something correctly kind of shines a dull light on you!

 

[rustred]

and thats what they do when they make a forklift out of these tractors , except the bigger ones. they turn the diff. around.

 

[FarmallA1943Eh]

Bright side is going through video, engine made 30psi oil pressure, pretty decent from my knowledge. Definitely needs carb and timing adjusted, but clutch works great, brakes work and looks like I'm gonna be able to push some snow with it this winter.

You guys saved me pulling my hair out all night over this, much thanks!

 

[rustred]

well gee wizz, when i read this there was no posts to read! i can see what u guys are typing either. not my fault had an interuption here. so no sense even trying to black ball me again, plus i dont type fast either. wow wow to you. so am i wrong?

 

[rustred]

your welcome!

 

[used red MN]

Okay rr, guess I will give you a break this time. As you can see if you READ my post that Sam actually beat me, but I also had the same proper diagnosis!

 

[rustred]

this reminds me of the time my dad had a 1965 ford 1/2 ton. the rear diff give up , and we had the old 1965 pontiac on blocks. he took the complete diff out of it and put it in the ford. then once done he had 3 reverse gears and one forward. then he flipped it over and used it a bit till he got the same diff from an auto wrecker. fords had ball brgs. in the axles and chev had rollers. he would say once i put o load on that ford it makes rollers out of them balls.

 

[SkipperII]

There's an old saying; I have learned far more from my mistakes, than I have from my successes. I think it fits.

 

[Rich'sToys]

Also, the engine rotation is counter clockwise when sitting in the seat, as stated....WHICH MEANS..that when cranking it from the front, you are turning it clockwise, as the original poster stated.

 

[gene bender]

the engine does not run backward are you sure the gear in the rear end isnt put together wrong thats the only way it would make the tractor move backward

 

[Rich'sToys]

He already stated that that was the case.