M25 alternator mount cracks gear case cover

[mherrcat]

I have the alternator adjustment all the way out, and the belt is still not tensioned properly.

Try a slightly smaller size (length) belt?

The M18 engine has the same original bracket as the M25 bracket that we keep hearing about breaking. The thing is, I have only heard of the M25 bracket breaking, not the M18. I bought the replacement bracket for my M18 but have not installed it yet...

Did you have to replace the manifold studs when you put the new bracket on? If so, was it difficult to remove the old studs? The original studs on my manifold are not long enough to get the nuts on with the new bracket. (New studs were included as part of the bracket kit package.)

 

[bknight365]

Try a slightly smaller size (length) belt?

I agree - this is the easiest solution.

Did you have to replace the manifold studs when you put the new bracket on? If so, was it difficult to remove the old studs? The original studs on my manifold are not long enough to get the nuts on with the new bracket. (New studs were included as part of the bracket kit package.)

I did have to replace the exhaust manifold studs. I was not one of the lucky ones. For some people, the stud unthreads from the block, but for me the nuts unthreaded from the stud. I was therefore forced to remove the exhaust manifold in order to replace the studs. It wasn't too bad.

 

[mherrcat]

Thanks. I bought two new exhaust manifold gaskets and an exhaust elbow gasket for the project; the M18 is only 2-cylinder. Not looking forward to the job since, in my case, there is very little room to work. I figured while I have the manifold off I could have it sand blasted and re-painted though.

 

[eherlihy]

Try a slightly smaller size (length) belt?

That will not work with the M25. There is just barely enough room to fit the coolant hose along the engine and run it between the engine and the lower arm of the bracket. A shorter belt would cause the arm to be closer to the engine, and the hose would no longer fit.

Did you have to replace the manifold studs when you put the new bracket on? If so, was it difficult to remove the old studs? The original studs on my manifold are not long enough to get the nuts on with the new bracket. (New studs were included as part of the bracket kit package.)

Yes, I did. I carefully sprayed the studs with PB Blaster, and let them sit a while. Then, I backed the nuts off, and removed the old bracket. Once the bracket was off, I again carefully sprayed the studs with PB Blaster, and then took two nuts, and put them on the stud. I tightened the nuts against each other, and then backed out the inner nut. The stud came out easy as you please...

 

[eherlihy]

thanks for the picture. Its just like mine, but with a different alternator. It looks like you're nearly out of tension adjustment also.

That is a 90A alternator.

Actually, I can continue to raise the adjusting arm. The only thing that holds the arm in place, and the alternator in position, is the friction between the arm and the bracket, caused by the tension from the bolt.

As I said, I am not very impressed with this design, or the kit.

 

[mherrcat]

If you are still monitoring this thread, one final question.

When you removed the manifold studs did you have to remove the manifold as well?

I was figuring the manifold would probably have to come off or risk an exhaust leak around the old gaskets. That was when I planned to repaint the manifold. But if the manifold does not have to come off, maybe I'll leave it as it is and just replace the alternator bracket.

 

[Maine Sail]

If you are still monitoring this thread, one final question.When you removed the manifold studs did you have to remove the manifold as well?I was figuring the manifold would probably have to come off or risk an exhaust leak around the old gaskets. That was when I planned to repaint the manifold. But if the manifold does not have to come off, maybe I'll leave it as it is and just replace the alternator bracket.

If the studs are too short the manifold must come off. You will need three manifold gaskets as well..

 

[mherrcat]

Do you happen to know a torque spec on the nuts for the manifold/bracket studs?

 

[Norwester]

21 years later... 256891 retrofit/conversion kit is now over $600.00 dollars from distributors.
IF YOU HAVE ONE LYING AROUND... pm me, please. Oh.....maybe you know of a used one attached to some dead M25 engine.
Maybe, I own the last Westerbeke M25, which still needs the alternator retrofit.
Excellent resources, with pictures, and step-by-step instructions will help this potential winter project. Kudos to those sailors (especially in Gig Harbor)!
Here's a picture of my M25 with recently replaced Oberdorfer pump (some filing required) and raw water hoses. Not pictured are the newly installed o-ring kit for the Groco raw water strainer, and vinegar rinsed Sen-Dure 2" heat exchanger with new cap & gasket.
If not a retrofit this winter...then rebuilding/restoring of fuel system.
(I apologize in advance for cross-posting to forums with this retrofit topic.)
Surprise me with some good news.
Happy Holidays.

 

[Prairie Schooner]

@Norwester - ". . . recently replaced Oberdorfer pump (some filing required) . . "

Our new O-pump was a sweet 1:1 replacement. I'm curious what you needed to file.