The Fordson Tractor Pages Forum

My Diesel Fordson Super Major TBH won't start. Here's what I think I know.

What it does: Turns slowly for maybe one turn of the fan, sometimes less than one turn. Then it stops, and when you stop it rolls back slightly.

Tractor was shut down normally after having run it for maybe an hour that day. Did not notice anything unusual the last time it was running (other than power steering fluid was very low -- filled reservoir.) Came back next day, tractor would not start.

What I've done so far:

1. Replaced battery recently. Last one made it 10 years, new one is a month old. Tractor was running and starting fine since battery was replaced. Battery voltage is 12.9 V before starting. It's a big battery, commercial scale from Autozone.

2. Replaced starter. Same effect.

3. Removed hydraulic pump on the front of the crankshaft. Just to make sure it's not froze up. No difference in starting.

4. Removed power steering pump to make sure it's not froze up. Not much difference, maybe turns just a bit easier, hard to say?

5. Tried jumping it from another battery, just in case. No difference.

6. Tractor has decompression lever. It is in the down position. I raised it and put it back (to verify it's not froze or anything), but didn't try starting it with lever up. Have never used it, only recently learned what it is for.

7. Pulling the tractor is not really an option. Has loader on it that is down, and hoe is down too. Plus, I don't have much space.


In conclusion, the crankshaft rotates so the engine does not seemed to be seized. But it's really hard to rotate it, either by hand or by the starter.

What should I do next? Thanks in advance for your help. Really appreciate it. I've her for about 2.5 years, so I'm definitely still learning.

Had exactly the same problem with mine which turned out to be a corroded head gasket allowing coolant into one cylinder.
Using several socket extension rods I turned it over one cylinder at a time, one out of the four pretty much locked = combustion space filled with water.
If nothing else works suggest you have the head off, don't risk ether or it might become more costly than a new gasket !

If the starter is alright and you got a good battery installed it should turn over well, unless the engine is blocked somewhere.
So Rick could be right, that the pistons aren't moving well.
Can you rotate the engine by hand?
Are you pushing down the clutch while starting?

As an update:

I read a little more about the decompression lever, and decided to give that a try.

I had my wife crank it over with the lever raised (clutch down). That got it spinning. Then I lowered the lever while it was still cranking, and it started.

I stopped at that point to celebrate some success!

Now I need to get back to see if it will start normally again.

mathias1 wrote: ↑

Wed Apr 08, 2020 4:24 pm

If the starter is alright and you got a good battery installed it should turn over well, unless the engine is blocked somewhere.
So Rick could be right, that the pistons aren't moving well.
Can you rotate the engine by hand?
Are you pushing down the clutch while starting?

Can rotate by hand, but barely, and maybe only a quarter of a turn or less.

Yes, pushing the clutch down while starting.

oehrick wrote: ↑

Wed Apr 08, 2020 1:09 pm

Had exactly the same problem with mine which turned out to be a corroded head gasket allowing coolant into one cylinder.
Using several socket extension rods I turned it over one cylinder at a time, one out of the four pretty much locked = combustion space filled with water.
If nothing else works suggest you have the head off, don't risk ether or it might become more costly than a new gasket !

Thanks. See my update about getting it spinning with the decompression lever up. Then it started once I lowered it, while it was still spinning.

I'll get back at it shortly.

Thanks again for everyone's comments.

Dear Hobo

If one cylinder is hydraulic-ing because of coolant in cylinder, you need to find out which one(s), or if you don't use the decompression lever, you could bend a connecting rod. Fill the radiator up with coolant (is it low?) leave for a period that it usually takes to refuse to turn over (a day or so?) Take out the injectors just prior to spinning it over with the starter. Water/coolant spurting out of one or 2 cylinders will tell you which ones have the problem. Mind your eyes, it can really whoosh out sometimes. Cracked liner, cylinder head gasket blown are usual culprits. Good luck. Tim E

Timeee wrote: ↑

Wed Apr 08, 2020 6:46 pm

Dear Hobo

If one cylinder is hydraulic-ing because of coolant in cylinder, you need to find out which one(s), or if you don't use the decompression lever, you could bend a connecting rod. Fill the radiator up with coolant (is it low?) leave for a period that it usually takes to refuse to turn over (a day or so?) Take out the injectors just prior to spinning it over with the starter. Water/coolant spurting out of one or 2 cylinders will tell you which ones have the problem. Mind your eyes, it can really whoosh out sometimes. Cracked liner, cylinder head gasket blown are usual culprits. Good luck. Tim E

What do you mean by "if I don't use the decompression lever?" Is starting it using the lever as I described a problem, at least during testing?

Thanks for your help.

hobo13 wrote: ↑

Wed Apr 08, 2020 8:47 pm

Timeee wrote: ↑

Wed Apr 08, 2020 6:46 pm

Dear Hobo

If one cylinder is hydraulic-ing because of coolant in cylinder, you need to find out which one(s), or if you don't use the decompression lever, you could bend a connecting rod. Fill the radiator up with coolant (is it low?) leave for a period that it usually takes to refuse to turn over (a day or so?) Take out the injectors just prior to spinning it over with the starter. Water/coolant spurting out of one or 2 cylinders will tell you which ones have the problem. Mind your eyes, it can really whoosh out sometimes. Cracked liner, cylinder head gasket blown are usual culprits. Good luck. Tim E

What do you mean by "if I don't use the decompression lever?" Is starting it using the lever as I described a problem, at least during testing?

Thanks for your help.

hobo,

The lever should only be used to turn a cold engine by hand (you can put a handle on front of the tractor). The decompression lever shifts the valves and when you start your engine the pistons can touch these valves, which leads to damage on the valves and/or pushrods. The push rods are the connection between the valve rockers under the valve cover and the camshaft, which is located in the lower part of the engine block.
There seems to be something blocking the engine, When a cylinder is filled with water, the engine won't be able to compress, as water can't be compressed.
Best thing to do is take of the rocker cover and take out the injectors. It's not a difficult job. Just make sure don't drop any bolts in the engine. When you have the injectors out, it should be possible to turn the engine by hand using a big pipe wrench or spanner on the crankshaft nut in the front.

mathias1 wrote: ↑

Wed Apr 08, 2020 10:02 pm

hobo13 wrote: ↑

Wed Apr 08, 2020 8:47 pm

Timeee wrote: ↑

Wed Apr 08, 2020 6:46 pm

Dear Hobo

If one cylinder is hydraulic-ing because of coolant in cylinder, you need to find out which one(s), or if you don't use the decompression lever, you could bend a connecting rod. Fill the radiator up with coolant (is it low?) leave for a period that it usually takes to refuse to turn over (a day or so?) Take out the injectors just prior to spinning it over with the starter. Water/coolant spurting out of one or 2 cylinders will tell you which ones have the problem. Mind your eyes, it can really whoosh out sometimes. Cracked liner, cylinder head gasket blown are usual culprits. Good luck. Tim E

What do you mean by "if I don't use the decompression lever?" Is starting it using the lever as I described a problem, at least during testing?

Thanks for your help.

hobo,

The lever should only be used to turn a cold engine by hand (you can put a handle on front of the tractor). The decompression lever shifts the valves and when you start your engine the pistons can touch these valves, which leads to damage on the valves and/or pushrods. The push rods are the connection between the valve rockers under the valve cover and the camshaft, which is located in the lower part of the engine block.
There seems to be something blocking the engine, When a cylinder is filled with water, the engine won't be able to compress, as water can't be compressed.
Best thing to do is take of the rocker cover and take out the injectors. It's not a difficult job. Just make sure don't drop any bolts in the engine. When you have the injectors out, it should be possible to turn the engine by hand using a big pipe wrench or spanner on the crankshaft nut in the front.

Thanks for the explanation. I'm an engineer, but an electrical one, haha. So trying to learn a lot. Appreciate the help!

I watched a video on removing the injectors. Agreed, seems doable. Once I remove the injectors, would I see water in the cylinder? And how would I get the water out? Sorry, if that's a stupid question, I'm trying to learn.

Also my tractor is a TBH. The hydraulic pump is connected to the front of the crank shaft. Though I did disconnect it already to make sure it wasn't seized.

Had the very same problem, solved by removing, cleaning and greasing all the battery and solenoid connections. Check and recheck all the heavy electrical connections, particularly the earth leads. A bit of corrosion can seriously reduce the available amps giving the 'flat battery' effect. A slave battery connected direct to the starter solenoid bypassing the battery leads and switch gear can quickly show if the fault is electrical (spins and starts up), or mechanical (no difference). Spinning over with the decompression lever could also point to a lack of amps.
From what I remember, positive earth vehicles are supposed to be more prone to electrical corrosion.

As a curiosity, when you started it with the decompressor, did you get any coolant out of the exhaust?

Yup. Like Hairy Bear said. Any liquid out of the exhaust? Dandy Dave!

I run two 12volt batteries in parallel. I have two suppers and both have the same problem. I have even used new starters from Bareco, but in the end two batteries in parallel works best. Kind regards.

Have you replaced the solenoid ?
I thought my starter was bad and it turned out to be the solenoid wouldn't pass the amperage needed.

Fixed with $7 part:
My tractor would turn over with the compression release open and partially turn over with it closed. I replaced the battery, battery cables and the solenoid with no change. I removed the starter and then removed the band covering the brushes. I found the problem. One of the brush springs was broken. I replaced the broken spring and fixed the problem.
I purchased the spring from Amazon.
Dts New Starter Brush Holder Spring for Lucas M45,M50,M127
https://www.amazon.com/gp/product/B07N1 ... le_o01_s00

The spring can be found elsewhere by searching using "LUCAS" " Brush Holder Spring" and the numbers stamped on the starter. Mine was M45G 26172L.

Note: The armature and winding will smoke within seconds if the starter is stalled. Don't keep power to it when it is stalled.

I think everything stamped on the starter should be used.
Davie's one reads Lucas M45G CW84 12V 26143N 2 63.
It certainly is worth inspecting things first, worn brushes in particular or brush springs broken, deformed or missing. You're very right to look at the battery first, old batteries struggle to hold a charge for long, and even if it's a new one, it can still be low for other reasons.
Sandy