Yanmar 3ym30 starter solenoid

[chris in SG]

I'm looking for some practical advice. I've had a recurring problem of a poor connection from battery cable to starter solenoid, which I have always managed to resolve by removing the cable, cleaning and replacing.

Unfortunately the end result has been that I've gradually damaged the thread on the solenoid +ve connection. It is now officially 'stripped'. I suppose this intro is a pathetic way of explaining that I didn't carelessly overtighten on one occasion - not that it matters now.

Does anyone have any advice? One option would be to try to use a die to create a new smaller thread. Since the connector 'post' is either brass or copper, this will obviously mean that I would need to be so carefully torquing it that I wonder if it would last.

If I remove the starter, does anyone know if it would be possible to get a competent machine shop to make a new threaded 'post', or is the internal construction of the solenoid too delicate?

I really don't want to be ordering a new starter+solenoid!

[tkeithlu]

Best replace it, I think. The solenoid itself is not expensive.

https://www.amazon.com/SOLENOID-YANM.../dp/B07H1L719F

[tkeithlu]

There is a background message in this for you. Yanmar and other manufacturers do not design their own solenoids, starters, water pumps, and what have you. They take something off the industrial shelf that will do the job. They then have to maintain a parts inventory at considerable cost to them for a small market over a long period. Therefore their prices for parts are high. Sometimes, very high. Sometimes, obscenely high. If you can find the parts on the same industrial shelves, they are cheap.

A Westerbeke starter for a Universal M25 baby diesel is something like $1,200. It's the same starter as on a Kubota tractor, and it's on Amazon for $70.

Have you got a plan for preventing this annoying problem from happening again? Good luck with it.

[chris in SG]

Many thanks for the helpful advice. It now seems obvious that you are correct - this is far too important to justify a dodgy repair.

I could not find an equivalent Amazon example for the 3YM series and I can see that the 3GM is different, but it's interesting to see that whilst the external casting is combined with the starter motor, the solenoid appears to slot in as a cartridge. Interesting to note that the Amazon product was reviewed by one buyer as follows:

"Bottom line is the solenoid fits and works for my Yanmar 3GM. However, I did have some trouble with installation. The electrical posts on this solenoid are some sort of brass or bronze so are not as strong as you may expect from that size of thread. I discovered this when I broke one of the terminals off during installation."

Of course, that's no excuse. In reality, when I have checked all the battery connections (yet again) I have been tightening the positive in same way I tighten the negative lead to the engine block, which is a steel bolt. So I have definitely learned a lesson.

With your guidance, I found a UK supplier of engine parts offering starter plus solenoid for a very reasonable price, and described as "A quality Yanmar 3YM30 Starter motor, manufactured by a Bosh (sic) group company". So I guess I know what that means..

I've never kept a spare starter motor onboard (where to draw the line, adding weight?) but I will feel a little comfort in having a spare from now on.

[Compass790]

Originally Posted by chris in SG

Many thanks for the helpful advice. It now seems obvious that you are correct - this is far too important to justify a dodgy repair.

I could not find an equivalent Amazon example for the 3YM series and I can see that the 3GM is different, but it's interesting to see that whilst the external casting is combined with the starter motor, the solenoid appears to slot in as a cartridge. Interesting to note that the Amazon product was reviewed by one buyer as follows:

"Bottom line is the solenoid fits and works for my Yanmar 3GM. However, I did have some trouble with installation. The electrical posts on this solenoid are some sort of brass or bronze so are not as strong as you may expect from that size of thread. I discovered this when I broke one of the terminals off during installation."

Of course, that's no excuse. In reality, when I have checked all the battery connections (yet again) I have been tightening the positive in same way I tighten the negative lead to the engine block, which is a steel bolt. So I have definitely learned a lesson.

With your guidance, I found a UK supplier of engine parts offering starter plus solenoid for a very reasonable price, and described as "A quality Yanmar 3YM30 Starter motor, manufactured by a Bosh (sic) group company". So I guess I know what that means..

I've never kept a spare starter motor onboard (where to draw the line, adding weight?) but I will feel a little comfort in having a spare from now on.

The great thing about having a spare is that usually that part never fails

Still I'm guessing yr vessel is a cat so one spare for 2 engines isn't too onerous. On the other hand you have a spare engine so no need to carry so many spares. It's a puzzle.

Hate to think what yanmar would charge for a "genuine " starter or solenoid.
If they are made in a joint venture factory the quality can be right up there.
If not the reverse can apply.
tkeithlu told it as it is
All manufacturers are getting increasingly cunning to try & make it harder for you to do DIY repairs or parts substitutions.
After all a 2000% markup is much better than a mere 100%