i am thinking of repowering from 5411 to M20 in my C30. Has anyone used the M20? Will it fit in the same area as the 5411? Any issues or extra work/materials?
Universal M20
- Thread starter lpbosch
- Start date
LP,
I did this several years ago. My engine is the 3M20A & it's worked well for 12 years.
I would suggest you look into the correct 2-3 blade prop/pitch for the increased HP.
I can remember I had only 8 HP under cruising speed @ the prop because of HP reduction.
I couldn't get out of my own way in seas & currents. You will like the increased power pal.
I have a 1980 Cat & should have the drawings I made of the new motor mount brackets. I had a welding shop
make them up for me out of stainless plate. The motor footprint will probably be different. I didn't see what year
boat you have in your profile, but is these may be of help, let me know.
CR
I did this several years ago. My engine is the 3M20A & it's worked well for 12 years.
I would suggest you look into the correct 2-3 blade prop/pitch for the increased HP.
I can remember I had only 8 HP under cruising speed @ the prop because of HP reduction.
I couldn't get out of my own way in seas & currents. You will like the increased power pal.
I have a 1980 Cat & should have the drawings I made of the new motor mount brackets. I had a welding shop
make them up for me out of stainless plate. The motor footprint will probably be different. I didn't see what year
boat you have in your profile, but is these may be of help, let me know.
CR
LP,
Glad to help.
Ps: do your profile for your boat, it will be useful in future threads.
Here are my sketches. If you have questions, PM me & we may want to talk via phone.
CR
LP,
I should have mentioned, that I do no longer have an (AARGH) stuffing box.
I have a waterless PSS shaft seal. Just so you know.
CR
I should have mentioned, that I do no longer have an (AARGH) stuffing box.
I have a waterless PSS shaft seal. Just so you know.
CR
I have the M-18 in my Mark II (1988). I realize that when the time comes and I decide to move the boat from Lake Lanier (north of Atlanta, GA) to the Intracoastal Waterway (ICW) for coastal cruising, I will be challenged with the 14 horsepower in heavy tidal/current areas like Georgia and the Carolina's. A three bladed prop for a bit more torque might help, but the M-18 was short lived on the Mark II and even as an optional engine because it was not a great improvement over the earlier Universal with 11 horsepower. The three cylinder M-22 and M-25 would suffice if I decided to repower. Your in the Gulf and these engines would provide the power to get you ahead and out of trouble. Tough choice I know, but if your going through all that trouble or removal and replacement consider the larger engine, which I understand will fit just fine. By the way I was on my buddy's 1980 Cat 30 with the M-11 years ago on a run from Pensacola, Fla to Mobile, Ala. When power was needed the damn thing was slow!!!!!!
Bob
Bob
BO
I would love a M25X but they are currently a bit out of my range. This is why I was thinking either M20 or Yanmar diesel model 2gm 15HP (if it will fit).
I would love a M25X but they are currently a bit out of my range. This is why I was thinking either M20 or Yanmar diesel model 2gm 15HP (if it will fit).
When Catalina upgraded the engine they went to the M25 which is I think 21hp, and some said that was still too small. The M20 is only 16 or 18 (I don't have my references handy) so that's not a huge improvement. 20-25 hp would be more fitting for a C30. Unless you already have the M20.
On the other hand if you're in salt water and the 5411 doesn't have the fresh water add on, it may be about done anyway. Raw water cooling and salt water are not the best combination.
LP,
These bracket mounts do not have to be stainless, that's only what I did. I also looked at the 25XP
but, decided it was too long based on my stuffing box & I did not want to modify the front door
cover area. It's not only the HP but, prop size & pitch can make a marked difference.
When aligning the motor & shaft, I would do it in the water & not on blocks. My boat sat
on blocks in Florida weather for three weeks & a tilt adjustment was needed (the boat sagged somewhat).
Give your boat a day to relax in the water then do the alignment. I feel this is crucial for correctness.
I can only speak from my experience.
I also used my halyards to drop the engine (250 lbs. approx.) thru the hatch cover & was able to do
the alignment myself sans, a mechanic's fee. These options would depend on your experience
with engines. Either way, alignment is just a true longitudinal run & the correct angle of tilt.
Do it in-water pal.
CR
These bracket mounts do not have to be stainless, that's only what I did. I also looked at the 25XP
but, decided it was too long based on my stuffing box & I did not want to modify the front door
cover area. It's not only the HP but, prop size & pitch can make a marked difference.
When aligning the motor & shaft, I would do it in the water & not on blocks. My boat sat
on blocks in Florida weather for three weeks & a tilt adjustment was needed (the boat sagged somewhat).
Give your boat a day to relax in the water then do the alignment. I feel this is crucial for correctness.
I can only speak from my experience.
I also used my halyards to drop the engine (250 lbs. approx.) thru the hatch cover & was able to do
the alignment myself sans, a mechanic's fee. These options would depend on your experience
with engines. Either way, alignment is just a true longitudinal run & the correct angle of tilt.
Do it in-water pal.
CR
LP,
I want to mention this.
The sketch that has the shown & opposite hand, are the rear support brackets. You will see a larger hole on the vertical side. Memory says that looking from the engine rear, the hole is only for the left bracket. This is an access hole to get to the zinc stick replacement in the heat exchanger. No hole is needed on the opposite bracket.
I got these style new motor mounts. Match up the vertical dimensions for a good fit. These are DF-100 mounts available on E-Bay
Let me know as you delve deeper into this having any questions pal.
CR
I want to mention this.
The sketch that has the shown & opposite hand, are the rear support brackets. You will see a larger hole on the vertical side. Memory says that looking from the engine rear, the hole is only for the left bracket. This is an access hole to get to the zinc stick replacement in the heat exchanger. No hole is needed on the opposite bracket.
I got these style new motor mounts. Match up the vertical dimensions for a good fit. These are DF-100 mounts available on E-Bay
Let me know as you delve deeper into this having any questions pal.
CR