Hitachi starter motor failed on Yanmar 3JH4E

[MikeCondor]

Hi all-trip 103, engine hours ~ 850, in Hanse 388. Starter motor failed. Dissecting it shows major failure centred around bent brushes, commutator. Has anyone seen this before, any comments? Not covered under extended warranty.

[stormalong]

Looks to me like it overheated which caused the damage. Does it smell like it has burned? Has the engine been cranked for long periods of time? Could the solenoid have been stuck on after the engine started?

[MikeCondor]

Hi- thanks! No burn smell, It made no noise at startup so maybe it got stuck on prior long run (6 hrs at 2,000 rpm) I’ll try to figure if release function is sticking in the gear that sticks out to engage engine. There was no visible damage to planetary gear.

[MikeCondor]

& Ill dissect solenoid for your suggestion on that.

[Scubaseas]

Are the field magnets intact? I've seen this kind of damage on permanent magnet style starters like your where someone beat the starter which can break the field magnet. Something clearly was stuck in there.

[Jammer]

Probably started with a bearing failure on the commutator end. Clearances are tight and any runout causes parts to hit other parts and the whole thing just grenades.


My advice would be to just replace the whole thing and think about something else. They fail for various reasons and aren't worth a great deal of analysis.