Replacing an M25XP with a Betamarine ?

[FastOlson]

As I contemplate my off-season list of maintenance and upgrades due for our 2300+ hour 1988 Universal M25XP, I have done some preliminary measurements to study whether a Betamarine 25 would be a "close enough" drop in for it.
Our original Hurth 50 is starting to make some noises under load, also.

Just curious... anyone done this swap for an aging M25 or M25XP in their boat?
How did the (vertical) alignment with your existing prop shaft work out?

Thank You!

 

[Mark Maulden]

Just went through this with a Beta 35 replacing an old Volvo. I had new stainless rails made to accept the current inserts on top of the bearers to accomodate the Beta and supplied mounts. This was cheaper and faster than having Beta make new mounts per YOUR measurements. Beta will make mounts to spec. Also, Beta publishes all their drawings on their websites with all the dimensional info. Websites are a little strange but between the UK, NC, and west website, the info is there..we splash on friday!! BTW, 2200 hrs is not much. Why are you thinking repower?

 

[FastOlson]

While our engine is not "ancient", this proposed change-out really is more about the years rather than the hours on it. While the short block may go on indefinitely, all of the peripherals do need replacing or rebuilding as time goes by. Other than replacing most of the hoses about a decade ago, it's never been "opened up" for anything other than a valve adjustment.

Thinking seriously of a repower because I may have to remove the present engine to get at some pan oil leaks. While it's out we need to rebuild or replace the orig. Hurts trans which sometimes has a bearing howl at some rpm's, and it's long out of production. While the trans. is off we would replace the torque plate.
What with already preparing to replace the old wiring harness and the whole exhaust system... it seems like a good time to..... step back a bit and consider just changing out the whole enchilada. We will probably have this boat for another ten years, and our cruising plans will take us hundreds of miles away from any towing services.
No decision yet, and I am just fishing for any input from other sailors that have replaced the same (very common) OEM Universal diesel in their boats.
Thanks.

 

[jibes138]

I just replaced a M25 with a Beta 25. All we had to do was add some spacers under the motor mounts to raise it a little higher, about 3/4 inches to get the tranny lined up with the shaft. The engine height is equal or a little shorter than the M25 so it fits the space very well. Also had to replace entire exhaust as the Beta requires a 2 inch exhaust while the output flange on the M25 is 1-1/4. Assume double the engine cost by the time you get done unless you install it yourself. In addition to the engine, new exhaust, shaft checked at a machine shop for condition, new shaft coupling, new propeller, hauling, crane time to pull old engine and install new one, remote tank for coolant to raise it higher than water heater, raw water hoses. New vented loop for raw water. You may need a new raw water through hull and seacock for 3/4 inches. My original scoop strainer was 1/2 inch and the Beta requires 3/4. I had previously installed a 3/4 seacock a few years back. Sanding and bottom painting while boat is hauled. Checking for leaks and stuffing box adjustment once launched, sea trial, propeller pitch adjustment to get engine RPM's at max throttle. You may need new engine control cables if they are old. I had new battery cables made up instead of buying a crimper and doing it myself, easier to install while engine is removed. Panel installation required some surgery to the mounting area in the cockpit to enlarge it a little. New motor is great!

 

[FastOlson]

Dave, thanks a bunch for the narrative! I have been trying to accurately measure the center of the present shaft connection to the transmission and compare that to the published height for the Beta. By golly it does look like there is a height difference, and I do have about two inches of height (total) to spare now. The width of the Beta is slightly less, which is nice given that the original engine really fills up the bay.
Sounds like your front-to-back distance did not change enough to require a shorter shaft.
Exhaust hose up-size would require a new transom outlet, and our boat has a 3/4" cooling water intake. Probably a good time to upgrade from the old Racor to a new 500 series, as well.
How is the TCM 40 transmission working for you? Did the new engine come with the "reverse bell crank" to reverse the action of the throttle cable? Which alternator did you choose? Serpentine belt, I presume?
We already replaced both cables about a decade ago, so at least that's done.
Oh, and did you use the Flex Coupler that they say comes with the engine. I was about to try to add one anyway for the old engine to try to tune out (or lessen) some vibration still present after some delicate alignment work was done.
And, Thanks Again... for taking time to write!
Regards,
Loren

 

[jibes138]

I went with standard alternator 40 amps, I don't use much electricity. Serpentine belt. Yes I used the flex coupler but had to add a jumper wire to get electrical continuity to the shaft. I did have some continuity about 5 million ohms :>) Yes a new exhaust outlet was needed. No idea on the throttle linkage. Transmission is fine no complaints. Some vibration on engines is from natural frequencies and are a design issue, not an installation issue. Solution is change RPMs to not operate in that range. Coupling may have nothing to do with it.