Visit our Popular Forums

scargo · 24-07-2023, 18:47

I need to rebuild and probably repaint two Yanmar SD20 saildrives. I am looking for a list of parts to replace. Diaphragm replacement is due too, so basically I need to replace everything that needs to be replaced.

Anyone has gone through such a process and has an electronic list of parts and willing to share it ?

Also, any recommendation on the type and or brand of paint to apply ?

Thank you

**skipperpete** · 25-07-2023, 01:25

How deep do plan to dive into the SD 20 rebuild ? A full rebuild is fairly complicated in that you need more than just the bearings and seals, there’s some fairly precise measuring to do to get the gear mesh and backlash correct, nothing beyond the ability of a committed owner but it will test your resourcefulness making up a few special tools.
IMHO still the best saildrive around and well worth the effort to rebuild provided there are no gears that need to be replaced..... that’s when it starts to get expensive.

**GordMay** · 25-07-2023, 03:37

Yanmar Sail-Drive OPERATION MANUAL [SD20, SD50, & SD50-4T]
includes:
Repairing Damaged Coating, and Periodic Maintenance Procedures [begins page 38]
➥ https://www.yanmar.com/media/global/...OM_27MAR09.pdf

SERVICE MANUAL ➥ https://j109.org/docs/yanmar_sd20_sa...al_epb5547.pdf

PARTS CATALOGUE ➥ https://j109.org/docs/yanmar-sd20-sa...ts-catalog.pdf

scargo · 25-07-2023, 12:05

Quote:

Originally Posted by skipperpete

How deep do plan to dive into the SD 20 rebuild ? A full rebuild is fairly complicated in that you need more than just the bearings and seals, there’s some fairly precise measuring to do to get the gear mesh and backlash correct, nothing beyond the ability of a committed owner but it will test your resourcefulness making up a few special tools.
IMHO still the best saildrive around and well worth the effort to rebuild provided there are no gears that need to be replaced..... that’s when it starts to get expensive.

I wasn't planning on replacing the gears unless it is needed.
The thing is, I bought this boat (a 42' cat) less than year ago, one engine was replaced last November, the other one, I rebuilt the water cooling system and it is working fine. When I started sailing I discovered that both saildrives were leaking oil including from between the saildrive flange and the engine. The previous owner got the boat for five years and did no maintenance on the saildrives. So I must replace the diaphragm to be on the safe side.