We recently bought a 1984 Catalina 30, our first boat. It is a beautiful boat! In great shape, great electronics, obviously well cared for. One possible problem I have noticed is that the Universal M-25 runs a bit hot, about 195-200F at 2000rpm. when I slow the engine to 1500 the temp drops back to 180 or less. I have been through everything I can think of to locate a problem - the raw water through hull, strainer, impeller, heat exchanger. Also the thermostat looks fine and the coolant level is fine. I did find a small stick (about 1/8"D lodged in the elbow before the raw water strainer and thought for sure that that was the problem, but after removing it there was no difference in temp. Although the manual says that the temp should be between 165 and 195, everything else I have come across says it should not be above 185. What is really the max operating temp for this engine? Do I have a problem or am I just making one up from inexperience?
Overheating M-25 ?
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heat exchanger?
OH - I had a overheat problem - noticed water flow out transom was reduced. Found the exit nipple on the heat exchanger where the hose attaches to take the salt water to the muffler box - was plugged with salt. When I removed the hose the nipple was packed with white rock like salt. Just a thought.
OH - I had a overheat problem - noticed water flow out transom was reduced. Found the exit nipple on the heat exchanger where the hose attaches to take the salt water to the muffler box - was plugged with salt. When I removed the hose the nipple was packed with white rock like salt. Just a thought.
Try a new 3 inch HX
Our M25 did just that (in 1998 on a 1986 boat). I removed the original 2" HX a number of times, found that the tubes were clear but the inlet or outlet on the seawater side was all crudded up. Banged that out a few times. Finally got a new 3 inch HX, no problems. Your temps are not unusual. They're also within specs, right? Only downside is when you need full throttle for a long period. 180 is fine, 200 is pushing it for extended periods, but OK for short spurts. Ours now runs at 163 consistently. Some will argue it's too cold. Just fine for me. Also try your C30 Association website. Could also try our C34 website, Forum section, Message Board, do a search on heat exchangers, lots of posts including some more detail from my posts there. ('www.c34.org') The C36 Association also has lots of information. The C30, C34 and C36 share MANY of the very same systems. You should check them all out. Stu
Our M25 did just that (in 1998 on a 1986 boat). I removed the original 2" HX a number of times, found that the tubes were clear but the inlet or outlet on the seawater side was all crudded up. Banged that out a few times. Finally got a new 3 inch HX, no problems. Your temps are not unusual. They're also within specs, right? Only downside is when you need full throttle for a long period. 180 is fine, 200 is pushing it for extended periods, but OK for short spurts. Ours now runs at 163 consistently. Some will argue it's too cold. Just fine for me. Also try your C30 Association website. Could also try our C34 website, Forum section, Message Board, do a search on heat exchangers, lots of posts including some more detail from my posts there. ('www.c34.org') The C36 Association also has lots of information. The C30, C34 and C36 share MANY of the very same systems. You should check them all out. Stu
Overheating M25
You may be airbound which can be teadious in resolving. Go to the catalina 30 website where you will find a detailed description, step by step on how to take care of this. http://www.tcsn.net/bosun/c30/cat30info.htm
You may be airbound which can be teadious in resolving. Go to the catalina 30 website where you will find a detailed description, step by step on how to take care of this. http://www.tcsn.net/bosun/c30/cat30info.htm
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