RANT ON: If you own an M-18, M-25 or an M-25XP with the old style bracket, and have NOT done the alternator bracket upgrade, DO IT NOW!
This information has been out as common knowledge now since the early 90's, June of 1991 to be exact. It may even affect some early M-25XP engines not just the M-25. There is NO EXCUSE!
Here is the Westerbeke Service Bulletin:
Universal / Wsterbeke Service Bulletin - Alternator Bracket Failures
Why is this so important you ask? Take a look at this photo. This blue peeling painted item is the timing gear case. It is a MAJOR job to replace it.
This engine had already experienced ONE failure of the timing gear case. Sadly the people who put it back together still did not upgrade the alt bracket. A 3K bill for a job done incorrectly, and then had to be redone, is really sad, but it happens...
Beyond that this timing gear case is NO LONGER AVAILABLE! You break this gear case cover and your engine is now SCRAP METAL. According to Westerbeke Kubota discontinued it & Westerbeke can not get them. Even if they could get them the last pricing for that timing gear case, which is part #300140, was $1261.40.
Parts You will need if you break the timing gear case:
Timing Gear Case Part# 300140 - $1261.40 (Will need a used one. Part is now DISCONTINUED!!)
Timing Gear Case Gasket Part# 300180 - $34.00
Alternator Bracket Upgrade Kit Part# 256891 - $163.90
Exhaust Flange Gasket Part# 298600 - $3.20
3 Manifold Gaskets Part# 299435 - $9.57 Each