I've got a GY6 /ODS157FMI series - 125 cc 4 Wheeler with electric start. (Raytech CT-125) The motor turns over slow like it has a dead battery so I replaced the battery with a brand new fully charged one and I get the same thing. I take the spark plug out and the motor turns a lot quicker without the compression obviously and gas is getting to cylinder but I don't think the motor is turning fast enough to fire. I have replaced the starter and checked valve clearances to .005 and .004 at TDC. Any ideas on what else could be wrong? It sounds like a dragging starter or a dead battery so I took the chance on replacing both. Fail 🙁 Before I dump more money in parts anyone have suggestions? Thanks

 

Take the plug cap off and leave the plug in. If the engine now spins faster, the spark timing is out, or the one way clutch for the starter is slipping. You can't alter the timing unless the flywheel has slipped on the crank but that usually puts timing so far out that it doesn't slow the starter. I have known new CDIs to alter the timing though. The slipping starter clutch is a common problem. If removing the plug lead doesn't alter things, it still can be a slipping clutch, or there is resistance on a thick wire (this includes earths) between battery and starter, check all connections.

 

[QUOTE=merryman;3508826]Take the plug cap off and leave the plug in. If the engine now spins faster, the spark timing is out, or the one way clutch for the starter is slipping. You can't alter the timing unless the flywheel has slipped on the crank but that usually puts timing so far out that it doesn't slow the starter. I have known new CDIs to alter the timing though. The slipping starter clutch is a common problem. If removing the plug lead doesn't alter things,


Thank you for the ideas. All the YouTube I watched I couldn't find anyone replacing the starter clutch on this style motor. Is it on the starter gear side of the motor and what exactly does it do? I think I could tackle replacing that.

This I haven't tried. Thank you