bymiller
Active member
- Joined
- May 19, 2013
- Messages
- 30
- Fluid Motion Model
- C-24 C SE
- Hull Identification Number
- FMLT2160D707
- Non-Fluid Motion Model
- Sea Pearl 21 sailboat
- Vessel Name
- Daycare
- MMSI Number
- 367647960
All last summer I was unable to keep the main belt tight. It would become loose within just a couple of hours of tightening it. Thinking the alternator was sliding on the bracket I tried various lock washers and other things to keep the bracket tight. The whole front of the motor was covered with black rubber dust. The belt on the motor looked good but I replaced it with an exact replacement, a NAPA Premium XL 25-9385. It still would be loose within a couple of hours of use. When I say loose I mean it would deflect an inch or more between the alternator and the engine pulley. Wefings tightened it for me early this year with the same result.
After much thought I figured this couldn't be caused bu the alternator slipping on the adjustment bracket. There are too many of these motors in use for too long to have a design problem like that. I also figured that if Wefings tightened it that it should not be slipping. It finally dawned on me that the belt I was using was the proper length but not the correct size. Close examination showed that the belt was riding very deep in the pulleys. I ordered a genuine Yanmar belt from Wefings. When compared to the NAPA belt it was wider and I think the angle of the V may be different. When installed it sits flush with or a little above the tops of tops of the pulleys. I haven't had a chance to run it yet but I feel confident this has fixed it.
The moral of the story is that if you want to use belts other than those sold by Yanmar be sure the replacement is the correct width as well as the correct length. All belts are not created equal.
After much thought I figured this couldn't be caused bu the alternator slipping on the adjustment bracket. There are too many of these motors in use for too long to have a design problem like that. I also figured that if Wefings tightened it that it should not be slipping. It finally dawned on me that the belt I was using was the proper length but not the correct size. Close examination showed that the belt was riding very deep in the pulleys. I ordered a genuine Yanmar belt from Wefings. When compared to the NAPA belt it was wider and I think the angle of the V may be different. When installed it sits flush with or a little above the tops of tops of the pulleys. I haven't had a chance to run it yet but I feel confident this has fixed it.
The moral of the story is that if you want to use belts other than those sold by Yanmar be sure the replacement is the correct width as well as the correct length. All belts are not created equal.