JD H Firing issues

[Pensfan1983]

Hello and thanks for taking a look at my ad!

I posted on here recently and thanks to some people, I was able to find the brackets for my hood. I"m hoping someone can help me with my latest issue in this restoration project.

I have a "41 JD H that I"m restoring. I"m having issues with getting fuel and spark to the motor. The Mag and carb have both been rebuilt. It"s still a 6V setup and it sort of sounds like the starter is dragging a little bit and won"t crank fast enough to fire it. Its the original starter and I had it checked before mounting it and it cranked fine.

I"m asking if anyone has any tricks or insight as to what I can to do get this thing running! And I have put it in time and still no luck!

Thanks for your time!

 

[Radiator Bolt Man]

You have two definitely separate issues when you say fuel and spark, or talk of having rebuilt both carburetor and magneto! Either of these being dysfunctional will prevent an engine start-up. You need to do some basic troubleshooting to see just what you do have.

IGNITION ISSUE

Clearing up a myth – there is no such a thing as having to crank a magneto-ignition engine “fast enough to fire it”. You can take that to the bank! The engine should start by just “tipping it over”.

Why? Magnetos have two stages of timing, starting timing and running timing. Starting timing is designed to deliver ignition when piston is at Top Dead Center or TDC. If fire were delivered earlier – like 25° before TDC, there would be a tremendous kick-back, and such would destroy your starter.

The magneto’s impulse mechanism comes into play when starting, and kicks out once engine speed reaches about 250 RPM. Below 250 RPM, you should be hearing a solid clicking sound from the magneto – the impulse at work! Are you hearing the IMPULSE clicking?

Go to the URL cited below, and once there, scan across to ARTICLES/DIAGRAMS, and there - under ARTICLES 1, select the drop-down called ELECT SYSTEMS. Study that piece to get the background you are seeking on magnetos. If your Maggie is freshly rebuilt and it is indeed rotating with the engine, you should have fire! Fire will alternate from one terminal to the other and come when you hear the impulse mechanism click. This and all of the data in the piece I am sending you to is contained in the John Deere Model “H” Restoration Guide – I feel like I am re-writing the book for you!!!

FUEL ISSUE

You either have fuel to and from the carburetor or you don’t – should be easy enough to verify before chasing demons as to why there seems no fuel in the firing chambers. Open the fuel selector valve (3-way) and the fuel shut-off (at sediment bowl). Then holding a catch basin under the carby, open the drain cock. You should have a steady, unbroken stream of fuel coming out. Troubleshoot as needed.

Initial settings of the carburetor needles is not critical, but a nominal setting would be for IDLE at roughly 1-1/2 turns out, and LOAD at roughly ¾ turns out.

Once again – back to the URL cited below – Under ARTICLES 1, see CARBURETORS; another excerpt from the Restoration Guide.

STARTING THE ENGINE

Do you have any form of an owner’s manual for your tractor? Do you have some knowledge of how to start a Deere tractor? Help us to understand how well equipped and/or familiar you are with the task set you face. (PatB)
Restoration Site, JD H

 

[John T]

If the starter cranks slow, first thing Id do is remove, clean n wire brush, n reattach each n every battery n starter n ground cable connection. Then make sure the battery is good (have it load tested) and fully charged. On 6 volt systems I advise the use of 0 or 00 battery cables and a high CCA rated battery.

If the mag was rebuilt, Id hope it and its spring trip and impulse are all okay, see if it throws a good visible BLUE not any faint thin wimpy hard to see yellow spark. SLOW TURNING HAS NOTHING TO DO WITH HOW WELL A MAG CAN FIRE AT CRANKING, so slow cranking isnt the problem as far as a spark ifffffffffff the mag is good???

After she fails to start are the plugs bone dry (may need carb adjusted or needs more choking) or wet (maybe too much choke)


Verify a strong blue impulse spark,,,,,,,,,adjust the carb,,,,,,,,,see if shes getting plenty gas when cranking (look at plugs),,,,,,,try carb at slow idle setting when starting

John T

 

[steveastexas]

had pretty much the same thing ,spent lots of money , went a head and did a valve job and away she went. STEVE

 

[Pensfan1983]

Thanks for all the help! I am happy to report that I took a second look at the carb and I was trying to start the old girl with the throttle wide open! I fixed that problem, hooked the battery up and she fired right up! Little smoke at first (been sitting for 25 plus years!) but once the initial smoke cleared, it putt-putts just like it should with no smoke, good oil pressure and no major issues!

If I remember, I'll post some before and after pics on here once I get it on here.

Thanks again!

 

[Radiator Bolt Man]

Pensfan - It is so good to hear you have overcome! These old relicks don't demand rocket science, but they do have nuances we need to know, and how to start one is job 1. Thank you for coming back with feedback, and if I helped - I am pleased as well.

I have all of the books you would ever need for your "H" tractor (Owner's Manual - both vintage and comtemporary, Service Guide, and Parts Catalog, and more). You can take a peek at the URL cited below. (PatB)
Restoration Site, JD H