Mercury Mark 35a - another setback - starter motor

Well this is turning into quite the project. I have been using a starter motor to start my engine. Today that starter decided to stop working. No indications as to why, no burning, arcing or anything. Just worked one second, I went inside for 5 minutes, and it wasn't working after that.

Anyone have any suggestions on this?

I pulled the starter apart to see what was going on and it seemed ok. There was continuity from power input to the wires all the way around. There appeared to be some spring-loaded contacts mounted to the wall of the motor at the very bottom. They seem like they are meant to wear away. They were very worn and short, but still made contact (until I pulled it apart, they sprung out, and now I can't get it back together because they've sprung into the spot where the rotor is supposed to go).

Are there any cheap replacements out there so I can avoid using 60 year old starter motors in the future?

It sounds like the brushes have worn away and aren't making contact; in the past I went to a small engine electrical shop and bought brushes that were almost the same size, then filed them to fit. You could do this or take it to them for brushes and bushings.
The brushes have to be silver soldered to the terminals or crimp connected, which is the only difficulty.

I think I'm just going to try to replace it with something new. I don't want to deal with an unreliable starter. There seem to be a few good candidates out there.

I'll call them and ask for exact dimensions before buying anything. Some of them look very close, just a different number of teeth on the gear, and I can always swap gears.

One example below.

https://www.dbelectrical.com/produc...VB4eGCh196g1IEAQYAyABEgIwKvD_BwE&gclsrc=aw.ds

So I popped off the bottom part of the starter motor to get a better look. How do these brushes look? I don't know what they regularly look like. They seem to be pushing up against their contacts pretty well, so I'm not sure how that could be the problem, but like I said, I don't have any experience with this.

I also got the replacement starter motor today. It fits into the screw mounts, which is the biggest thing, but has a different gear, It can be retrofitted by just grinding down the smaller spiral thread it uses to make splines, so that's my backup plan as of now.

Looks like a lot of brush left to me - what do the other ones in the cap look like, how is the continuity between the field windings and a brush - it should be 0 ohms.
What size are the pics you're uploading I haven't been able to upload one since the "E award" one.

There aren't any other brushes in the cap, at least I didn't think so. I'll give it another look tomorrow and also do those continuity tests.

The pictures are just iPhone pictures that I email to myself then post from laptop. When I send the pics to myself I select the "Large" option - it's usually around 1-1.3 MB

They look fine to me too. I suggest you clean up the commutator with fine sand paper, oil the bushings (top and bottom) and reassemble. Oh, and be sure the brushes move freely, with lots of spring action, so they don't bind.


Jeff

PS: After a half decade of messing with old Mercs, I've only found one starter I couldn't resuscitate in th above fashion, and it came from 'submarine'.

Jeff-----Have you only worked on motors for 5 years ??

Hah! Dumb guy, dumb guy! I meant half a decade. Seesh.

Jeff

So, 5 years...?
Sorry couldn't help it..

I noticed.

Jeff

PS: Of the 5 or 6 novels I've written over the decades, of which I've proof read over and over, I can't believe how many really dumb typos are still there!

In metric a ---decade---is 10 years.-----Now a century is 100 years !