1948 John Deere A, firing, wont start

I have been trying to get the A started. New points, cap, rotor,
good spark. New carburetor, getting fuel. It will pop, something
see a flame come out the muffler, sometimes a backfire. The
exhaust manifold is warm, when cranking, but no start.



I removed the intake tube, thinking maybe there was some
blockage, and not getting enough air.



I have posted a video, attempting to start.



Any tips would be appreciated!

https://share.icloud.com/photos/0c1ufHZoIjq2AcTfpNYZHHnAA

Verify that you have good fuel flow by removing the drain plug from the bottom of the carburetor. Is the float set correctly. Did you check that setting? It has to allow the fuel to flow, but also close off the flow when the level in the bowl is correct.

Have you checked the valves in the head? Are any of them stuck open or shut? The engine has to be able to breathe.

Flow from bottom of carb when loosening screw.

When I was putting on the new carb, the float appeared to be in the correct position.

change your SPARK PLUG WIRES around. !!

I tried that as well, no avail!

Going to check the valves tomorrow!

Have you run a compression test?

Need about 60-70 PSI minimum to start.

A spoon full of oil in each cylinder might bring it up if it's been sitting a while.

I have not, will check that out too!

It has been sitting for about a year.

Had it running prior, then was using it one day and was sputtering and died. Had put some new plugs in to make
It back to the house. Rebuilt the carb, and was not able to get it started again.

Have you made sure the timing is set correctly?

Yes, checked timing today, I m good there.

That looks like a backfire. Perhaps your timing is off or more likely you have one or more exhaust valves that do not close.

Check the distributor shaft for size to side movement. Sounds like what I had on my B. After installing a rebuilt distributor the tractor starts and runs like a new one.

(quoted from post at 19:55:26 09/16/22) That looks like a backfire. Perhaps your timing is off or more likely you have one or more exhaust valves that do not close.

Click to expand...

One of the exhaust valves was stuck, was able to get it unstuck pretty. Made a slight adjustment to the float setting, and it is in time.

No clue what to try next.

see, ... we dont have all the information. took it as it was running,... then u changed plugs and did the carb then would not start ,that
means self inflicked problem. why u adjusting float? set it level and its good. and the float being off a bit has nothing to do with a no
start and backfire. a backfire means your out of time! check your compression then post it. make sure the firing order is correct. get
number one on compression at TDC and then see which plug fires. what happened when you switched the wires? was it still backfiring??? if
not that is a good sign. people vever post actual pec setting... ooh its in time well how do we know. post your point setting and your
timing and how you did it. then maybe the aahh haa moment might kick in . people think we are magician's. we have no eyes or ears on the
subject just what u guys tell us. so now u see why i am bitching so to say. i want actual facts. every thing is step by step. do one thing
and keep track of what you have done. record the facts.so when u post here u can post everything in order for a person to make a decision.
your unsticking a valve but not giving a compression reading to verify it has compression. and as you said was using it and sputtered and
died,... so either lack of fuel or no spark. are the plugs firing? old plugs no not cause a no start either. plus what is your carb
settings at?? we dont know you nor know what your mechanical skills are.

Rustred:

No worries, I understand your frustration, I have tinkered plenty, though not quitting my day job, the information/wisdom from youll is much appreciated.

-Over a year ago, it was running, started sputtering, then died. Plugs were fouled, put in new plugs, to get it to the barn. Wasnt running good, but made. Shut it off, and tried to start the next day, nothing. Took it to a guy to work on, kept saying he would get to it, never did so I brought it back home recently

-Installed new points, condenser, cap, wires.
I now have good spark.

-upon trying to start it, again, nothing. Took the carb off to make sure it was clean, discovered the bowl cracked, purchased a new carb.

-now to where I am at now, in video posted, it would fire, but not start. Sometimes a flame/backfire outside the muffler.

-someone posted about checking for stuck valves, so yesterday, removed the valve cover and saw that I had a stuck valve, was able to free that easily.

-I have never removed the magneto, as far as timing, I was referring to turning the flywheel, and listening to the click, and it clicked right on the mark on the flywheel, and the frame of the tractor.

-I have switched the wires around, and it does nothing different.

-I was reading about the the float adjustment, so that was why I was messing with that, so it was perfect, however thats not my main issue here. It is now not shutting off the fuel when the bowl is full (float is good), so there needs to be an adjustment so the needle is closing correctly, doing that tomorrow.
-I will do compression test tomorrow, and report back!

(quoted from post at 18:31:40 09/18/22) see, ... we dont have all the information. took it as it was running,... then u changed plugs and did the carb then would not start ,that
means self inflicked problem. why u adjusting float? set it level and its good. and the float being off a bit has nothing to do with a no
start and backfire. a backfire means your out of time! check your compression then post it. make sure the firing order is correct. get
number one on compression at TDC and then see which plug fires. what happened when you switched the wires? was it still backfiring??? if
not that is a good sign. people vever post actual pec setting... ooh its in time well how do we know. post your point setting and your
timing and how you did it. then maybe the aahh haa moment might kick in . people think we are magician's. we have no eyes or ears on the
subject just what u guys tell us. so now u see why i am bitching so to say. i want actual facts. every thing is step by step. do one thing
and keep track of what you have done. record the facts.so when u post here u can post everything in order for a person to make a decision.
your unsticking a valve but not giving a compression reading to verify it has compression. and as you said was using it and sputtered and
died,... so either lack of fuel or no spark. are the plugs firing? old plugs no not cause a no start either. plus what is your carb
settings at?? we dont know you nor know what your mechanical skills are.

Click to expand...

Didn t hit reply to your post, replied to your questions above.

And, 1 1/2 turns out on the carb needles.

Rustred,

-Point gap set at .21.

-compression on left cylinder, just under 50 psi. Right cylinder, just over 50 psi.

-pulled plug, plug is firing at top dead center. Switch the wires around, no change.

For spark ignition engines, the cranking motor should be used with the battery in full charge condition. Ignition wires must be disconnected from spark plugs in the case of spark ignition engines. Throttle should be set in wide-open position to provide normal volume of air to cylinders for correct reading. Spark plug should be removed only from the cylinder being tested to allow applying of the gauge. Removal of both spark plugs would result in a faster turning speed and, thus, a higher compression reading.

Model A

Cranking Speed 190 rpm

Pressure
A (All-Fuel) - 81.8
A (Gasoline) - 117.5

Allowable variation on No. 1 and No. 2 cylinders up to 10 %.

From John Deere field service bulletin 181-S, July 1951.

Try doing a compression test again after squirting some oil in cylinders and see if it comes up. If it does you may have stuck rings or a tired motor. If it does not you may have valves out of adjustment. Just a guess since it is a 48 it may still have the All-Fuel pistons in it, but 50 psi when it is suppose to have near 80 is not good.

This post was edited by Rodney51Cub on 09/19/2022 at 07:32 pm.

What did the plugs look like when you pulled them to check the compression? Black and sooty? If so you need to clean them with spray carb cleaner, a hand wire brush and compressed air. Or screw in new ones. I am not a Deere guy but is there a way to check valve timing on them. I think as a last resort you may have to pull the magneto and see if everything is right in the impulse. Maybe it catch when cranking slow by hand but not when cranking at starter speed. If it was a points machine I would have told you to replace the condenser. I am not real good with magneto note sure how the condenser in one of those That compression is a bit low but I think it should still fire and run on it.

Plugs were dry, slightly black. Exhaust manifold gets warm when
cranking, so I know its firing, as well as pulling the plug and
watching it spark.



As far as timing, I did have the marks on the flywheel, match the
mark on the frame. However, I pulled the plug and saw that I
wasnt getting spark at top dead center, adjusted the timing,

So I have spark at TDC.

So I did not put this in the last reply because it was getting long. Open the petcock and get a plug you know will fire, new or one out of you lawn mower that runs. Put the wire on it and hold it near the petcock. Is it firing consistently in sequence with the hiss of the petcock? I am no mag guy but I really think there may be a problem in the magneto and I feel it may be something like the impulse throwing the timing off at the speed the starter is cranking it. And like I said what about the condenser in the mag? You say the manifold is warm so it is firing that may be. But is it consistently firing at the right time. You may need to post this on the JD section so the 2 cylinder gurus can maybe lead you down the right path. What ever made it sputter and stop when you had problems the first time has not been found or you have created another unknown problem.