Members Login
    Remember Me  
Post Info TOPIC: Catalina 36 Engine Replacement

Veteran Member

Status: Offline
Posts: 77
Catalina 36 Engine Replacement

Read our Catalina 36 Repower Write Up -

Original Power

Original builds from 1982 started with 23 hp diesel engines as standard.  Later in this models history, the 36 Mk II was fitted out with up to a 35 hp engine.    

Repower Recommendations

The Beta 30 is a fine choice of power for the Catalina 36. It produces the power you need for motoring and low speed handling, while also providing excellent efficiency. The Beta 30 fits the engine compartment very nicely and the exhaust is properly located on the port side of the engine. This is important for easy installation when using the original Catalina muffler location and design.   

The Beta 25 has also been used in this application.

Beta 30 -

Beta 25 -

-- Edited by Bob on Tuesday 24th of December 2019 07:43:48 AM

-- Edited by Keith on Saturday 25th of January 2020 09:17:23 AM



Status: Offline
Posts: 1

Looking for additional details.

Do the muffler, furl or water filter need relocation to allow fitting the beta?

any problems with oil pan clearance?

Does the galley sink need removal to remove replace the motor?



Status: Offline
Posts: 1


I'm in the middle of a repower project w/ my 1985 C36 (Mk 1). Purchased the Beta25 w/ "atomic feet" (to match port to starboard spacing of OEM engine well) and PRM60 gearbox. To answer your Q's:

- I fully intend to re-use my original Aqualift water muffler. I assembled an exhaust riser to connect to Beta's 1-1/2" "stub" exhaust using:

  • (1) 1-1/4" x 5" nipple
  • (1) 1-1/4" x 10" nipple
  • (2) 1-1/4" 90 degree elbows
  • (1) 1-1/2" to 1-1/4" reducing 90 degree elbow
  • (1) 1-1/4" Westerbeke injection nipple
  • (1) 1-3/4" x 6" Silicon Hump Hose

The wet exhaust from the Beta25 is 1", so to use the Westerbeke injection nipple and existing 5/8" hose loop through the anti-siphon fitting, you will need a reducer. The raw water intake on the Beta is 3/4" as opposed to the 5/8" line connected to the OEM water strainer... you will need to replace the output fitting on the water strainer and the hose.

You do not need to remove the galley sink to install the motor, HOWEVER, you will want to remove the wood bulkhead separating the galley from the aft cabin in order to install the exhaust riser. I'd refer you to for guidance on how to do that, but beware, there are MORE screws holding the bulkhead in place than documented on this site.

Another excellent resource is on the site. If you are a member you will be able to download a writeup of another C36 owner who has also done the installation. A couple of key takeaways from the article:

  • You will need to use 1" shims under the engine mounts to align with the prop shaft and stay within the Beta spec's. My installer used a 3/4" shim under the front-starboard mount because he claimed that the stud on the mount would have interfered with the diaphragm fuel pump.
  • The gear selector on your old Hurth transmission is the opposite of the way the selectors work on Beta's transmissions, i.e. the morse cable needs to "push" the selector forward for forward gear as opposed to pulling the cable aft which is the way it works on my boat. Beta recommends using a vertical as opposed to horizontal mounting bracket and rotating the selector switch positions 90 degrees to resolve this problem.  Unfortunately the exiting gear selector morse cable will not be long enough to work with this bracket configuration. I'm opting to fabricate a bracket similar to the design sketch in the C36 writeup. This is the last "challenge" that I'm currently working on.

A few more tips:

  • You will need to order the 5 meter engine harness, the stock 3M harness will not be long enough. Also the extension harness has a spare wire you can use to connect your existing fuel pump to accessory power on the ****pit control panel.
  • Regarding the control panel, none of the stock Beta panels will fit the existing panel cutout in your ****pit. I designed my own panel so that it would be a drop in replacement and I ordered my controls WITHOUT a physical panel. I had my design fabricated out of ABS plastic by providing a CAD file to the fabricator... it looks great, better than the original control panel. The custom design also allowed me to add a switch for the blower to the panel, which will not be present on any of the stock Beta panel. Lastly, I opted to upgrade to the B-panel which provides a gauge for the water temperature (recommended).

Bottom line, I think the Beta25 is a good choice to repower a C36, but it is far from a "drop in" replacement, as would be the case for any replacement engine except for another old M25.

Page 1 of 1  sorted by
Quick Reply

Please log in to post quick replies.

Tweet this page Post to Digg Post to

Create your own FREE Forum
Report Abuse
Powered by ActiveBoard