Cranking issue

[chris129]

Hi, I have a Jinma 254 and it cranks so slow that it will not start. I have tried 2 different batteries with the same result. When I bought it last year the owner told that he had just replaced the starter. Has any body have any ideas on what to check next?

[Ronmar]

If all your cables and connections are good, measure voltage at the large + terminal where it enters the side of the starter case and ground. You should not see more than about 2-3V of drop when cranking from the voltage measured at the starter solenoid terminal(battery voltage) if y0u have more drop than that you probably have a bad connection somewhere.

If the drop is not too bad, pull the starter, pull the end cap on the starter and inspect the brushes and commutator. You can pull the whole brush assembly by removing two bolts on the end and two philips head screws where the wires from the case windings connect to the brush holders.

Mine was doing the same thing, with good battery voltage while cranking(2V drop) but cranking horribly slow. There appeared to be some grease residue that had made it into the brush area, and all the carbon worn off the brushes was packed in there like paste. The commutator(place where brushes ride) was black, couldn't even see any copper. This mess effectively was shorting windings together and interfering with the magnetic field timing, preventing the starter from building full torque. Cleaned all the crap off(should be bright copper slats with grooves in between on the commutator) and re-assembled dry as the brush area should be dry with no oil or grease so the carbon can fall away to the bottom of the case. Put it back in and it cranks wonderfully now...