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Universal 25XPB

Jun 2, 2018
Catalina 28 mk ii Port Orchard
So I am looking at buying a Catalina 28 Mk II, and one of the things that spooks me is that it has a Universal 25XPB with a ZF10M gear box. It vibrates excessively at about 900-1000 rpm (yes I understand that the idle is set way to slow), and it smooths out when the engine rom is advanced to 1300 rpm or so.

One of the previous owners had the transmission replaced at 255 hours (when the boat was 4 years old). That was about 500 hours and 7 years again.

I know the 25XPB has a bad reputation of eating gearboxes. That scared me away from a Cat 310 I was looking at (owner had replaced the gearbox 2 years earlier).

Am I just paranoid from reading forum comments too much, or is this a real concern? $4-5k every 6 years on a transmission is a bit much.
Nov 18, 2010
Catalina 310 Hingham, MA
Yes, you need to idle a little higher. I also found that two key issues. The factory dampener plate is crap. It's plastic rybon style instead of metal springs. Pretty easy fix, search the 310 forum.

The second was the alignment. Really the engine bed needed to be higher in the front. The result was that the front mounts were all the way at the top of the treads and less stable. So there was a lot of movement. It might be responsible for the transmission issues and I was going through Cutlass bearings every 3 years, 100-150 hrs. So I had 1 inch stainless steel plates made to raise the front mounts. You could also do this with G10 board. Then I spent a good amount of time getting my alingment as perfect as possible.

Since making these fixes I have about 25k nm and 1,500 hours on the same Cutlass bearing and dampener plate with no other transmission/shaft related issues. Also, change your transmission fluid regularly. I do it every 4-6 months now but when I was a seasonal boater I did it every spring. I meet a lot of boaters that ignore that. When we bought Smitty she was 10 years old and had the factory tranamitrans fluid still.

Personally I really like the universal engine compared yanmars. The external heat exchangers are easier to maintain or replace, the raw water pumps can be switched easily from different manufacturers, the engine is simple and strong.

If I ever had to buy a new engine I would get a Beta Marine. Very similar to the universal but some better thinking towards maintenance.

Good luck and fair winds,

Last edited:
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Nov 18, 2010
Catalina 310 Hingham, MA
Also, I would check your tach adjustment. Most smooth out at 900-1000 and vibrate below. Shifting at 1300 would be bad for the transmission.
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Nov 22, 2019
Catalina Catalina 28 MKII Outer Harbour marina
The guys in this group are the best. It's all Catalina 28 owners. Great discussion threads and wiki. Free to be a member. Love to have new people. Lots of info on the engines, transmissions and prop alignment.