I am not sure if "undersized" is the right word for the heat exchanger on the M18. "Barely adequate" sound more like it. Especially, if you sail in 85 degree water like we do in FL. In cold water like you have, it should do just fine. It is probably normal to overheat at WOT. You should be running continuous between 2,100 and 2,600 rpm. That should give you between 5.2 to 5.8kts, depending on your prop being clean and how much junk you carry on board. Max rpm is 3,200 and you should not do that much for over 5 minutes. Don, #6293, Niceville, FL
--- On Sun, 2/14/10, dalzellandrew97 <[email protected]> wrote: From: dalzellandrew97 <[email protected]> Subject: [IC27A] Heat exchangers To: [email protected] Date: Sunday, February 14, 2010, 10:21 AM Some of my fellow Catalina 27 and 30 owners have told me that they have read that many Catalinas that have Universal Diesels are equiped with undersized heat exchangers. . I can run all day at 3000 RPM in 68 degree water on Lake Erie and maintain an engine temp of 160-165 degrees. However, if I go full throttle (3700-3800 RPM on my tach) the temp will climb to 0ver 200 degrees. I have replaced my impeller on a regular basis and checked the heat exchanger by removing the end cap to look for obstructions and check the zinc anode. I have also cleaned my raw water inlet strainer regularly and it looks clear. My boat is a 1986 model equipped with a Universal M-18 2-cylinder diesel that has only 220 hours on the meter. I seem to get plenty of cooling water flow out of my exhaust. Is there a chance that my OEM heat exchanger is undersized and should be replaced? If so, who sells them and what would I ask for? Are there any special installation problems? [Non-text portions of this message have been removed]
