M cranking slow ?

dacaseguy

Member
A friend bought an M tractor. He put a new battery, installed new heavy battery cables and replaced the starter button.
The tractor cranks over real slow. To slow to start. He took the starter to a starter shop and they said it was fine.
Any one got. Any ideas why it won’t crank properly.
Thanks
 
might be able to get an idea if could hand crank it. who knows what the engine's condition is. presume you are talking 6 volt battery. maybe its bad? is the tractor outside in the cold? did he have it running before or this first start? engine shot like crank brgs turned??
cyl's rusted?? valves stuck??
 
find another starter shop after feeling both ends of the cables after engine turns over just because cables are new doesent mean they are good. Take a hydrometer reading on each. cell of the battery. Another example of buying all new parts and not fixing the problem thats why aother check of the starter
 
I'd oil the bearings through the oil cup or the screw in the ends and see if they turn easier first. Also check for slop in the bearing to shaft clearance. IF the nose end has excessive slop the rest are not far behind and the armature is probably dragging. Oiling will help with turning after all when was the last time they were oiled 10,20 years ago.
 
If I'm thinking right, M's came with a BCI group 2 battery. Most stores only carry group 1 6 volt batteries. The spec's I looked at show group 1 at 600 CCA and group 2 at 780 CCA. Do you think the additional 30 percent cold cranking amps would make a difference if you are using an off the self group 1 battery?
 
It might make a small difference, but not enough.

What kind of testing did this starter shop perform to determine the starter was good? Hooked it to a battery, and it spun, therefore it's good? Most starters will spin when you hook them to a battery. There's no load.

Ideally the commutator would be dressed up in a lathe, new brushes, new bearings/bushings. Then the starter is as good as it can be.
 
At an autoparts store you will find a starter draw meter. It will cost less than $20.00. It has no wires hooked to it, it is just placed against the wire. When the starter is engaged, the current is shown on the gauge by a needle. If it is over 300, the starter motor needs attention. In the winter, an engine block heater (coolant tank type is best) will help make it turn well. Farmall Ms have a just adequate starting system when new. Jim
 
I rebuild them , checked the armature with vom ,got to Napa for new bushings , and eBay for brush kit , turn commutator as mentioned clean ti mica just below commutator bars, make sure everything is good clean grounds everywhere .
I watch the video on you tube how to . Rachel does a good job.
And Kane does good with his classing lathe how to turn commutator,
Another does good on checking armature with vom meter .
10w30 oil for winter
If all is connected it will whirl good 😌
 
I think the big question is 6 volt or 12? Most of these tractors have oversized pistons and higher compression then original so when its cold outside an M has a hard time stating on 6 volt even if everything is setup correctly. Check to see how much voltage you have at the coil while it is cranking over. A cheap volt meter may be to slow to see this. A final thought on starting an M on 6 volt. I bought a Super M that would start on 6 Volt but it had giant battery cables to prevent voltage drop. I still upgraded it to a 12 volt with a Delco 10SI.
 
When the 49M was new and later ours started good as we ground fee at least 2 times a week and pushed snow with the Super Six loader and big blade had to keep 1/4 mile lane open and another 1/2 mile on the farm to two barns where cattle were fed but every spring and fall i removed the battery and claned the posts and box had distilled water for the cells so things wre in shape tractors did not set outside
 
(quoted from post at 08:56:04 12/18/20) If I'm thinking right, M's came with a BCI group 2 battery. Most stores only carry group 1 6 volt batteries. The spec's I looked at show group 1 at 600 CCA and group 2 at 780 CCA. Do you think the additional 30 percent cold cranking amps would make a difference if you are using an off the self group 1 battery?

They were grp 3 but no longer made.

The new grp 2 is close to the same output.

Grp 1 ain't gonna do it on a good engine.
 
Should not even be a question

Go to 12 volt and your starting problems will go away

I see their are a lot of alternator options that are the same size as the generator to make it easy

Don’t be fooled by the 8v trick. Yea it is a little better starting but not the real fix

If you must or need to keep the tractor original get the best battery cables you can, clean up all the connections and coat them with something to prevent corrosion, clean up the generator and the 6v will work

Any corrosion and the 6 v system and you’ll have issues
 
My recommendation is go 12v. It's the difference between night and day when it comes to electrical performance. I offer a 12v conversion kit with a Hitachi alternator, mounting and tightener bracket, a 12v ignition coil with clamp and a number of other small items like metric bolts and even a small machine bolt for connecting the wires from the old voltage regulator together. The kits also come with an easy to follow set of instructions and a wiring diagram.

I have designed these kits to fit correctly with not modification. I make my own brackets, they are not from the land of "sometimes fits". I have made everything to fit and even the original belt fits. Check out my web site for more information at www.charliesrepair.com
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top