Catalina 36 and Universal M25 engine

[Casa Bonita]

I have a 1986 Catalina 36 that I love.

My Universal M25 likes to run hot it seems. At 2000 rpm it will run at 6 knots in flat calm seas but it runs hot...180 degrees and rising plus the hot engine smell. It has a 3" heat exchanger and my mechanic, who I trust, says the engine is fine. When I back it off to about 5 knots it will cool back down. My concern is if I'm going to weather in rough stuff the engine isn't going to be much help and I better have both sails up.

I sail in the Santa Barbara Channel so would really like to have more power from my engine. Short of replacing it for a larger one....any suggestions?

Bonne
"Casa Bonita"

 

[Stu Jackson]

Modified M25

I have the same engine and had upgraded to the 3 inch HX years ago. I have a 180 thermostat and the engine runs at 180 - 185 all day long at 2500 rpm at 6.5 knots with a clean bottom. I can peg it to 3000 ropm and it'll go up to maybe 190.

I don't understand your hot smell issue. The 3 in. HX is a great add.

"180 and rising..." means what??? Rising to what??? If it stays below 190 or 195 what's the problem?

Either change your thermostat to a 160, or check your system because it sounds like you have a leak somewhere if you think it smells hot.

You have nothing wrong other than the fact that you use a mechanic rather than doing it yourself. YOU need to know everything about that engine, not some mechanic who is gonna be sitting in a bar somewhere drinking on your wallet when your engine overheats. Really, get serious and learn about your engine. It's a lot less expensive that way, too.

You can get really inexpensive thermostats from Kubota tractor dealers. See this, reply #6: http://c34.org/bbs/index.php/topic,3133.0.html

I also recently wrote:

Give it a shot before ya call a mechanic (quality boat mechanic = oxymoron).

And if anyone has an argument with that concept, then, by all means, start writing down who are GOOD boat mechanics you've found, please, we could make a fortune writing good references and keeping them here on this board.

Good boat electrician: Ryan's Marine, Oakland, California.

 

[Stephen K]

Re: Modified M25

Possibly the thermostat, but I would check to see if the heat exchanger is restricted...either by broken impeller vanes or from crud...if it is, you can have it boiled out.
I have the 3 inch exchanger and can't get above 165 degrees...

 

[fdonovan50]

help with drafts Bonne

I have a 1986 Catalina 36 that I love.

My Universal M25 likes to run hot it seems. At 2000 rpm it will run at 6 knots in flat calm seas but it runs hot...180 degrees and rising plus the hot engine smell. It has a 3" heat exchanger and my mechanic, who I trust, says the engine is fine. When I back it off to about 5 knots it will cool back down. My concern is if I'm going to weather in rough stuff the engine isn't going to be much help and I better have both sails up.

I sail in the Santa Barbara Channel so would really like to have more power from my engine. Short of replacing it for a larger one....any suggestions?

Bonne
"Casa Bonita"

Bonne, Sorry that this is off topic. What are the drafts of the 1986 Catalina 36's? Do you also happen to know what the two draft choices are for 1985 or 1984 or 1983? We have found a couple of owner's manuals online but they don't state the year-they were on the owners site but we still are confused because people say that they have 5'10" drafts in 1983 and 1984 and there is no 5' 10" draft listed. There is a 1985 Catalina 36 for sale that lists a 5' 10" draft and that year may have overlapped with the 1986 when the 5'10" came out. These boats we are looking at are in the water and so we can't confirm that they are right or wrong without paying for a haul. Please let me know your thoughts. Thank you.

 

[Paul Montgomery]

Overheating

I have a Catalina 30 with the Universal M20 and am having exactly the problem you are describing.
At over much over 2000 rpm the engine heads north of 195 degrees and I get steam with the water out of the exhaust.
I have checked my raw water intake filter, replaced the thermostat with a new 180, replaced the raw water impeller, checked all the lines and am getting good flow through the system. I cleaned the heat exhanger with fresh water (not sure about the "boiling" referred to in other posts).
The problem continues.
I sail on Georgian Bay and sometimes need the power.
Did you get your problem solved?
Paul

I have a 1986 Catalina 36 that I love.

My Universal M25 likes to run hot it seems. At 2000 rpm it will run at 6 knots in flat calm seas but it runs hot...180 degrees and rising plus the hot engine smell. It has a 3" heat exchanger and my mechanic, who I trust, says the engine is fine. When I back it off to about 5 knots it will cool back down. My concern is if I'm going to weather in rough stuff the engine isn't going to be much help and I better have both sails up.

I sail in the Santa Barbara Channel so would really like to have more power from my engine. Short of replacing it for a larger one....any suggestions?

Bonne
"Casa Bonita"

 

[Casa Bonita]

Re: help with drafts Bonne

My boat, a 1986, has a draft of 5' 10" according to the spec sheet I got when I bought the boat. I can't imagine Catalina changing the keel length from year to year. Check for boats on yachtworld.com and see what the spec sheets on the listed boats say. Or you could call Catalina and they will tell you. Good luck!

Bonne