Farmall H 12 volt live hydraulic wont start

https://forums.yesterdaystractors.com/viewtopic.php?p=10562905#10562905
I am now almost 90% certain that I am in time close enough to start. I manually turned the crank pulley with a wrench with a finger in the number 1 spark plug hole and waited till I felt air push out so I knew I was on the compression stoke, I put a straw like piece of plastic inside the spark plug hole to verify the piston was at the top of the stroke. I then turned it to top dead center and turned the distributer until the #1 spark plug sparked. I have the air intake hose detached from the carb currently and when I try to start the H I would say that a vast majority of the times it fires, it backfires out of the air intake of the carb. What could be causing this. I have checked previously and there wasn't any stuck valves. This is now week 4 of trying to get this thing started. Any help is greatly appreciated, Thanks in advance!

Double check your firing order to the rotation of your distributor.

If that correct check the valve settings.

This post was edited by J.Wondergem on 06/03/2022 at 08:12 pm.

Air going past your finger can be confusing. Difficult to tell if it's
sucking or blowing. You need to verify compression stroke by watching
the valve trane. I have made this mistake myself. Your trouble
description sounds exactly like the timing is off 180 degrees.
Dave

Firing order is correct. How do I check the valve settings?

This post was edited by SoulFate15 on 06/03/2022 at 09:21 pm.

I used a piece of plastic and verified that the piston in cylinder 1 was at the top of the stroke, is that not enough? How do you check the valve Trane?

Everything Ive read has said that the distributer turns clockwise and that the firing order therefor follows clockwise, My specific H was converted to live pto and the distributor is now driven via a hydraulic pump shaft passing through the distributer housing and into the magneto housing. Im not sure but I've never considered that this conversion could be spinning the distributer counterclockwise. I will double check tomorrow.

(quoted from post at 19:54:17 06/03/22) https://forums.yesterdaystractors.com/viewtopic.php?p=10562905#10562905
I am now almost 90% certain that I am in time close enough to start. I manually turned the crank pulley with a wrench with a finger in the number 1 spark plug hole and waited till I felt air push out so I knew I was on the compression stoke, I put a straw like piece of plastic inside the spark plug hole to verify the piston was at the top of the stroke. I then turned it to top dead center and turned the distributer until the #1 spark plug sparked. I have the air intake hose detached from the carb currently and when I try to start the H I would say that a vast majority of the times it fires, it backfires out of the air intake of the carb. What could be causing this. I have checked previously and there wasn't any stuck valves. This is now week 4 of trying to get this thing started. Any help is greatly appreciated, Thanks in advance!

Click to expand...

That following two statements, one after the other, are confusing to me.

''I put a straw like piece of plastic inside the spark plug hole to verify the piston was at the top of the stroke''

''I then turned it to top dead center''

The ''top of the stroke'' and ''top dead center'' are one and the same, with no ''turning'' needed between them.

ANYHOW, as to the valveTRAIN, when #1 is at TDC at the end of the compression stroke, ready to "fire", the rocker arms should have released BOTH valves on that cylinder so there's actually ''play'' between the rocker arm tips and the top of the valve stems.

On the other hand, if the rocker arms are tight/lifting the valves on #1 you are one crankshaft turn "off" from the correct TDC.

What I meant was i was confirming that the piston was coming up (compression stroke) and I used a straw through the sparkplug hole to feel the piston come up to verify. I then turned the crank pully to the tdc mark. I apologize as I'm only 22 and still very new around this type of equipment. Hopefully this makes a bit more sense.

when you thought you were at TDC were both valves closed The straw just shows
piston is at the top but it could also mean exhaust instead of compression
stroke

In the link is a method to set the valve clearance by
turning the engine two revolutions. The valve
clearance spec for your tractor is 0.017 of and inch for
both exhaust and intake valves. It is set by adjusting
then studs in the rocker arms that have the ball ends
the push rods fit into. The clearance is checked by a
feeler gauge. You may have to determine if the mating
surfaces between the rocker arm tip and valve. This is
to make sure you are measuring the spot with the most
clearance. First thing I would do is with the valve cover
off watch the valves on number 4 cylinder as you turn
the engine. When the exhaust valve closes and the
intake is just starting to open stop at that point. The
timing mark should be lined up for TDC on number on
cylinder one. This assures the valve timing of the
camshaft has not changed or slipped. Seems like with
the compression reading you had it seems like it
should be on. Lastly to post a link as I assume you
tried above you need to use the ..Optional link

URL box then title it in the next box down. To post a

link in Modern View you click the URL button paste in
your URL then click the URL button again and you
should be good to go.
Edit: I believe the link I posted for the valve setting diagram was not allowed by YT.
I changed the link to a YT thread that has the diagram in it as a photo.
https://www.yesterdaystractors.com/cgi-bin/viewit.cgi?bd=farmall&th=1070091


This post was edited by used red MN on 06/04/2022 at 08:51 am.

I agree, sounds 180 off. Move plug wires around the cap, 2 spots, way easier than moving the distributor!!

air will also come out on exhaust stroke but not as much as compression you
are out 180 if its backfiring

Here's an animation of what is happening inside the engine.

Note that EVERY time the piston is at the top, both valves are closed, so you can't go by that.

That is why you feel for compression at the plug hole. When the piston is on it's way up on compression, when it gets to the top of THAT stroke is when the plug needs to fire.
4 Stroke Animation

I moved the sparkplugs two positions so that the firing order matches up with the distributor being out 180 degrees. There is a lot less backfiring but its still backfiring often. I have checked the valves and none of them seem stuck but at the same time I have never worked on valves so im not sure how to tell if they aren't behaving properly. I did double check and my distributor does indeed still turn clockwise even with the weird conversion. Thanks everyone for the suggestions. Keep them coming!