Starter problems 120 hp Force 98

Hi. I hope some of you can help me find out whats the problem with my starter (In Sweden where I live, Force engines are hard to find = no one to ask).
The starter spins but bendix gear does not engage the flywheel.
I have changed battery and polished all connections. I have lubricated the bendix spiral shaft (its now very easy to raise by hand).
I have measured the battery (12.9 V).
Then I measured the solenoid without the starter engaged = 12.8 V
With the starter engaged = 0 V
The starter gets 9,1 V when I measure it while its engaged.

If I engage the starter so it spins and take a screwdriver and gently push under the rotating bendix so it jumps up to the flywheel it almost stops and you can hear that the starter struggles to rotate. But it doesnt have the power to rotate the flywheel.

Someone?
(I hope you understand my not so good english )

Re: Starter problems 120 hp Force 98

I would try puting a battery charger on the battery and then try it. Speed is what makes the bendix jump up. The lower the voltage the slower the speed.

Re: Starter problems 120 hp Force 98

The starter may be bad. You might try cleaning the carbon brushes on the inside of the starter. Have you ever taken an electrical motor apart? The force starters are similar. If that doesn't help, then a new starter may be the answer.

Re: Starter problems 120 hp Force 98

Thanks for your answers.
Today I took a startcable and connected from the battery direct to the starter. And the result was the same (I wasnt sure if the selonoid was the problem). That test should tell me that its the starter. Right?
Even though the engine is from 98 it has only been running for 40 hours...

I have already taken the starter apart. And I cleaned the carbon brushes with a cloth. They looked ok.

I havent tried connecting a battery charger, but I took my car battery (from a large Land Rover) but that didnt help.

The owner before me has put a safetyswitch on the batterys minus side. Can that has something to do with my problem?

Of course I could buy a new starter, but I just whant to be sure that its the starter that is the problem...

Re: Starter problems 120 hp Force 98

The I doubt that the safety switch has anything to do with your problem. You can by-pass it if you want to be 100% sure, but it's looking more and more like you have a bad starter.

Re: Starter problems 120 hp Force 98

9 volt during start would be a reasonable number. In the old days, american autos had a dropping resistor at the coil because battery voltage dropped to 9 volts during cranking. The coil was a 9 volt coil and the resistor was bypassed during starting.

Anyway: Your starter is a high torque single speed motor. If you were to remove it from the engine and jump it on a good battery, it would (if good) spin so forcibly that it would want to twist out of your hand.

Spinning a starter with no load usually will tell you nothing about its condition with the exception I mentioned above.

Now, you say you cleaned the brushes, but did you check the condition of the pressure springs? Did you clean the copper commutator? If the commutator is carboned or if the springs do not hold the brushes tight against it, then the starter will not produce full power. If the brushes are worn down to the point where there is less graphite above the power wire than below, then they are worn beyond use. Replace them. Good brushes will be somewhere around 12-13 mm in total height. If they are 10 or less, then for sure, they are worn.

Your starter is most likely American Bosch and I would not be surprised if you could find European Bosch brushes and other parts to fit it.