I am repowering a Catalina 30 that had the old Universal M25(1985). Does anyone have any experience, concerns or opinions with the Universal M3-20B 20Hp verses the Universal M25XPB 25 Hp for this boat. I believe the original M25 was rated at 21Hp the new M25XPB is the same size and displacement, but is rated at 25 Hp.
m25 engine repower
- Thread starter ronc
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I have the M25 XPB
I have the XPB on a Catalina 30 and it is great. I doesn't use much gas and pushes the boat from 5.8- 8.2kts depending on wind and current. This is in the RPM range of 2200-2400. How does that sound?
I have the XPB on a Catalina 30 and it is great. I doesn't use much gas and pushes the boat from 5.8- 8.2kts depending on wind and current. This is in the RPM range of 2200-2400. How does that sound?
more like 23 HP
I also have the M25 XPB (original one from 1989) which is rated, according to the manual) at 23HP, but perhaps newer ones are more powerful. It is not a particularly powerful engine for a boat of the weight of a Cat30. Don't think you'll get much more than 5.5knts at 2400 rpm in calm conditions(unless you are riding a very strong current)and with strong headwinds and a chop the engine is adequate, but only just. Fuel consumption, though, is quite moderate. If I were to repower I would look at 26 to 30 HP, but that very much depends on the conditions in which you sail(or rather motor). If you don't have a lot of chop or very strong winds, 23 HP is ok. Literally: horses for courses.
I also have the M25 XPB (original one from 1989) which is rated, according to the manual) at 23HP, but perhaps newer ones are more powerful. It is not a particularly powerful engine for a boat of the weight of a Cat30. Don't think you'll get much more than 5.5knts at 2400 rpm in calm conditions(unless you are riding a very strong current)and with strong headwinds and a chop the engine is adequate, but only just. Fuel consumption, though, is quite moderate. If I were to repower I would look at 26 to 30 HP, but that very much depends on the conditions in which you sail(or rather motor). If you don't have a lot of chop or very strong winds, 23 HP is ok. Literally: horses for courses.
Engine ????? or Prop
I forgot to mention the transmission and the prop. This can change so many things performance wise. What do you do with your boat? Race, motor cruise, etc????
I forgot to mention the transmission and the prop. This can change so many things performance wise. What do you do with your boat? Race, motor cruise, etc????
I had a 30 with an M3-20B
The motor pushed the boat along just fine. In Maine we have huge tides and lots of rivers to get up on an outgoing tide and I never had a problem with either boat. I also owned a C-36 with a M-25 and it pushed that boat along just fine. I sail with the standard factory three blade you migh have a little more trouble with a two blade but the M3-20B will work fine on a C-30. You would probably find that a 16hp diesel would do the job in that boat too. I've also tried folding & feathering props and switched back to a standard three blade. To many problems with my folders / feathers..
The motor pushed the boat along just fine. In Maine we have huge tides and lots of rivers to get up on an outgoing tide and I never had a problem with either boat. I also owned a C-36 with a M-25 and it pushed that boat along just fine. I sail with the standard factory three blade you migh have a little more trouble with a two blade but the M3-20B will work fine on a C-30. You would probably find that a 16hp diesel would do the job in that boat too. I've also tried folding & feathering props and switched back to a standard three blade. To many problems with my folders / feathers..
M3-20B is a good engine choice
I have a M3-20B Universal w/ a fixed 3 blade sailor prop in my '89 Cat 30. It is rated at 18HP. Max RPM is 3600 as stated in the manual, but my engine will never see that RPM. At 2200 RPM or so the boat will cruise at 6.1-6.2Kts in flat water (GPS confirmed). I have powered at 6.3-6.4Kts w/an unloaded boat and fuel consumption goes from 1/3 GPH to over 1/2 GPH. The stern really squats down, so this speed and the 2500-2600 RPM have only been used to make a timely drawbridge opening. In big seas the boat powers to around 5.0-5.5Kts avg. My M3-20B is a great engine, trouble free 920 hrs. One raw water pump rebuild at around 750 hrs is the only maintenance other that routine normal items. I do not know the cost difference between the M3-20B 18HP and the M25XP 23HP. If cost were close, I would buy the extra 5HP. I am a Tim the Tool Man type though (more power)
I have a M3-20B Universal w/ a fixed 3 blade sailor prop in my '89 Cat 30. It is rated at 18HP. Max RPM is 3600 as stated in the manual, but my engine will never see that RPM. At 2200 RPM or so the boat will cruise at 6.1-6.2Kts in flat water (GPS confirmed). I have powered at 6.3-6.4Kts w/an unloaded boat and fuel consumption goes from 1/3 GPH to over 1/2 GPH. The stern really squats down, so this speed and the 2500-2600 RPM have only been used to make a timely drawbridge opening. In big seas the boat powers to around 5.0-5.5Kts avg. My M3-20B is a great engine, trouble free 920 hrs. One raw water pump rebuild at around 750 hrs is the only maintenance other that routine normal items. I do not know the cost difference between the M3-20B 18HP and the M25XP 23HP. If cost were close, I would buy the extra 5HP. I am a Tim the Tool Man type though (more power)
For what it's worth
I looked at repowering with these two engines several years ago & as I recall, the M25 is a few inches longer than the M20 (no real issue here for you). Also the motor mount footprint might be different (not sure, but would cost $ to get re-mounted). Also the tranny might be different, & that can run into the thousands... Check these facts before changing to the M20, otherwise stick with the M25...
I looked at repowering with these two engines several years ago & as I recall, the M25 is a few inches longer than the M20 (no real issue here for you). Also the motor mount footprint might be different (not sure, but would cost $ to get re-mounted). Also the tranny might be different, & that can run into the thousands... Check these facts before changing to the M20, otherwise stick with the M25...
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