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
, 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.