Perkins 4-108 - Cool Running!

[Trekka]

Last fall and winter I asked a lot of questions here, and posted a lot of pictures, as I first rebuilt the water pump">raw water pump, and then piece by piece removed all the cooling system hoses and parts from my boats Perkins 4-108. The engine, like so many aged units of its make and model, had been overheating. Badly overheating at 2000rpm and above. Paperwork of the deceased PO indicated he had battled the problem, too.

I worked in my spare time through the Fall and Winter, taking apart as much of the cooling system as I could, cleaning it up, repainting, replacing some hoses and thermostat. Eventually I reassembled all the components, reattached hoses and filled with a 50/50 premix of coolant. I ran the engine while in the slip, under load with prop engaged, but never took it out before hauling this Spring for "a week or two" of work. Early in August I relaunched with a few new seacocks, backing plates, bilge hoses, and various other essential items newly installed, or cleaned up and rebedded, including a new head and associated hoses.

So I was wondering if I had really solved the overheating problem, and it was with some trepidation that I planned a 32 mile move to a new slip. I expected to be sailing most of the way, as the weather report was 50% showers and T-storms and winds 5-10kts. The day started off with lowering clouds but by the timie we slipped lines the sun was shining hot with no clouds to diffuse it. The winds were minimal and in the direction of our travel, so canceled out any effect. With temps in the upper 90'sand past noon, I had no option other than to kick over the engine and wind it up.

For the next 6 hours the Perkins ran continually above 2000rpm. At least 3 hours was at 3000rpm, and the rest of the time between 2500-2800rpm. The temp was 170F most of the time, climbing to 180F for a little while after I throttled back and the coolant flow was reduced. No smoke, no odd noises, no problems!

It feels GREAT, after all this time and toil, to have a cooooool running 4-108! (Not a subject header seen very often, huh?)

[btw, @ 3000rpm to a 3 blade prop this CSY33 was making 6.9-7.4kts!]

[speakeasy]

Not a subject header seen very often, huh?

No indeed! Congrats! Having virtuous work rewarded seems rare these days and finding your efforts rewarded with performance is, well, inspirational. It's been said here that all 4-108's leak. Let us know if that too is false.

[SkiprJohn]

Hi Trekka,
Congratulations! It really sounds like you did a great job.
Did you change the prop any?
regards,

[bobfnbw]

Congrats!
Bet it felt good to know how your hard efforts paid off.
BTW, that exhaust hose size is your Perkins ?
What hose did you use when you replaced the old hose.
Bob

[ColdFusion]

Well done Trekka! There's nothing as satisfying as fixing a problem yourself. Here's to many more hours of cool running!