1985 25 hp mercury starter

MarsAngler40 · Sep 30, 2014

Bought a used boat and motor. Motor is 25hp mercury tiller steer. It runs great and starts in first 3 pulls every time.

The motor has an electric starter and when the button is pushed it engages but only turns the motor half way and then doesn't disengage. The battery is good, connections are good, just seems the starter is shot or possibly bent? Anyways, they are not that expensive for a new one but just wondering if anyone has any thoughts before I go that route?

crazymanme2 · Sep 30, 2014

Double check your connections.

MarsAngler40 · Sep 30, 2014

crazymanme2 said:
Double check your connections.

Done that, also skipped the button and connected battery direct to starter and had same issue.

Side note, live outside of Chicago but grew up in Zeeland, brother lives in West Olive.

marshman · Sep 30, 2014

I wanna say check the solenoid.. But I guess if it were bad, you'd have nothing...

Does the motor run fine??

I'd change the starter... Not all that hard to do...

kofkorn · Oct 1, 2014

If it is turning slowly, it can be a couple of things:

Low voltage caused by: poor battery connections, low battery, thin wire gauge
- try the stater a few times. Do a temperature check of all of the wiring contact points any bad connections will warm up.

Weak starter: windings shorting out, brushes making poor contact - shorted windings will cause the starter to heat up quickly. Starter will need to be disassembled to check the brushes. It's a good idea to clean up the brush contacts and armature when you have it open.

Poor positioning: If the starter is too close to the ring gear, the starter will work harder to turn it. With the way that you say that the starter doesn't disengage when it stops turning, this may be the issue. I recently had this on one of the motors I was working on. I shimmed it with a thin washer and it worked fine afterward.

Good luck!

MarsAngler40 · Oct 3, 2014

Thanks for the response kofkorn. I am going to try to re-position it as that is the only thing i have not tried. If that doesn't work ill just order a new one for the spring.