Starter Motor Deceased 2.25 petrol

Thanks John.

have it set up on the bench through the solenoid and measuring the volts at the starter motor terminal. The set up I have on the bench , the lead from the solenoid to the motor is not the biggest, I will try to find something bigger and see if it makes a difference.
The shaft moves about a mil or two max. No heat though that I can notice.
The solenoid pushes out 12 v . When I connect to the starter motor and it is running , I only see 7v. The commutator has some wear on it from the brushes.
cheers,
D

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Originally Posted by Dark61

Thanks John.

have it set up on the bench through the solenoid and measuring the volts at the starter motor terminal. The set up I have on the bench , the lead from the solenoid to the motor is not the biggest, I will try to find something bigger and see if it makes a difference.
The shaft moves about a mil or two max. No heat though that I can notice.
The solenoid pushes out 12 v . When I connect to the starter motor and it is running , I only see 7v. The commutator has some wear on it from the brushes.
cheers,
D

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Does the shaft move sideways? If the bushes are stuffed the rotor may be contacting the field cores. New bushes aren't hard to do if you can get some. Even just oiling the bushes can help sometimes. Try reading the voltage at the battery while the starter is spinning and showing 7V. Maybe the battery or the solenoid is stuffed.

If the shaft moves as much as you say, there is a very good chance the armature is touching the poles (they are magnetic and trying to pull the armature). There is no more than about a millimetre clearance (the bigger the clearance the less efficient is the electric motor), and as soon as they touch it is like a brake. If this is the case, it has only just worn this far, and the braking is enough to stop the starter turning when under load, but not when running free, although the friction is loading it and hence the high current draw and voltage drop.

The starter is quite easy to disassemble (see manual) and if it has been poling, it will immediately be apparent.

Thanks Gents - back in the shed for me when the Sun comes up.
Cheers,
D

back in the shed with all cables battery cable size . Measuring volts at battery = 12.5 at start after running for 30 seconds down to 11.3 and falling slowly.
back to measuring voltage at starter motor and getting 7ish volts.
There is movement of the armature shaft pushing in and pulling out say 2mm and up and down say 1 to 2 mm.
Always started fine even if not driven for a couple of weeks - up until it let me down last week.
cheers,
D

Herewith some pics.

I think I can see marking on the field cores? which if not caused by the wobbly armature shaft could I suppose have been by me when taking it to pieces.Not having really looked inside one before its hard for me to tell. Having dismantled it I can see what you mean by not much clearance - although hard to tell if rubbing when its all put back together. I think I will have to source a new one as this is my daily drive so I can get back on the road and further look into how this one comes to bits (read as will probably sit on the shelf for years) . It will start quite easily on the handle so thats another option.
cheers,
D

I don't see the marks you refer to - picture not in focus enough!

Better?
cheers,
D

Looking at the end of the shaft the bush hasn't had any lubrication for a while. Stick the endcap back on (without the body fitted) and see how much play there is between bush & shaft.
If there's lots the starter could be poling.


Colin

It doesn't look like its been poling, the scores from that are pretty obvious. Have you tried oiling the bushes and seeing if it spins better? You'd be amazed at how much dry bushes drag a motor down.

Ill have a go with some oil. I had this off last a couple of years ago. BIL was cranking the hell out of the truck testing a carb rebuild a mate of his had done and the starter died. He took it to an auto elec who said bin it. I cleaned it up and its run fine till now. I would have oiled it back then. There is slight play with the end cap on.
cheers,
D