Starter / generator problem

[casper4203]

My '90 marathon starts great and runs great. Occassionally, it lets the battery get too weak to start. I replaced the ragged out belt but after a couple days of steady use... I have to charge it up. I thought to maybe rebuild the generator. But would it still crank if it was in need of a rebuild.

[scottyb]

I think that 2 stroke has to be in gear to start? If so, put it up on jack stands and check the battery voltage when you run it. It should be above 12v standing and up to 14v when it is running mid throttle?

[Dave Box]

If it appears not to be charging then you can test to see if it is the generator or the regulator as follows.

Remove the thin green wire from the generator terminal DF. You should place a thin wrench under the wire to stop the stud turning.
Make sure the wire does not get caught up in anything and with the rear axle on stands or the drive belt removed start the cart.
Measuring directly on the battery you should see ~12 volts. Now ground the green wire and you should see ~18 volts.
If you do then the regulator is working and your problem lies with the generator.
The generator is pretty bullet proof so you may only have to change the brushes which is a fairly easy task.
There are 4, 2 for the starter and 2 for the generator, it is a good idea to replace all 4.
Good luck
Dave

[afzimm]

I had my starter/generator tuned up a couple months ago. Brushes, bushings, bearings and new paint for 99 bucks at a local electric motor shop. Starts and charges like new again.

[Mudbuster]

Im not sure about your 90 model but my 94 marathon has a removable cover on the voltage regulator and has a adjustment screw on it that can be tweeked to send the correct amount of charge back to the battery. I had a 84 yamaha g1 with the same voltage regulator that would not hold a charge and the adjustment fixed my problem. Just jack up the rear, put a volt meter on the battery and press the gas to check you output. You should see around 14v wide open throttle. If its lower, turn the adjusment screw clockwise on the voltage regulator and check again. This may fix your problem.

[casper4203]

Thank ya boys. I just came back from a week at the Ocean. Loved having it there. I will test the regulator and genny when I clean up from being away for 8 days.

[Chattybirds]

Originally Posted by casper4203

Thank ya boys. I just came back from a week at the Ocean. Loved having it there. I will test the regulator and genny when I clean up from being away for 8 days.

I am having a similar issue. Did you ever resolve this? Thanks.

[redcloud]

No one has mentioned how old the batteries are? Have the grounds to frame and block been cleaned and checked? Also check to see that the battery connections are real good. I had one that all was well but when I checked for ground past the battery connection right at the battery it was weak and was not a solid connector.
Have they been tested for bad cells or even proper levels of fluid? If you have a bad cell it can drain a battery while sitting and even while running when it gets bad enough. Just a thought and may not even apply if you have already delt with that.