I've had it...I don't care how much trouble it is and or how much it costs to fix, I'm going to have a Perkins 4-108 that runs at the proper temperature. I've been working on this since I got the boat. Since I just day sail mostly, it is not a big problem, but it has run me nuts. The latest twist is now that the temp gage seems to run hotter and hotter - up to 230, but the alarm
doesn't go off and the engine (and I have experience with diesels) doesn't seem hot or act like anything is wrong - you can still lay your hand almost anywhere on the engine when it is operating...New plan: I am going down this list until I fix it. I'll stop when the problem goes away.
1. Replace temp sensor and gage
2. take off every hose to every piece of cooling gear
on the engine and make sure that it is clear..I don't think this engine has ever had a disintegrating impeller, but I'm going to find out. Part of this will be backflushing all the cooling
system with pressure.
3. Pull the hose to the cooling elbow
and check it..although water flow out the exhaust
seems ok, and there is no steam being produced in the exhaust
4. I've cleaned the Heat Exchanger, and it looks ok inside, but I'll replace the heat exchanger.
5. New thermostat..don't think this is the problem, but....
5. New Water pump - anyone know the flow rate for a G65 Sherwood as used on the Perkins? i.e., how many seconds to fill a 5 gallon bucket or some such rule
6. New Transmission Oil
Cooler - Long shot, but if I've done all of the above.....
7. New Yanmar
Any suggestions, additions, or comments on the list above will be appreciated....