Perkins 4-108M 50HP overheating.

CharlieCobra · #1 (**permalink**) 10-04-2007

1994 engine. It ran fine until yesterday and then seemed to be running hot, smelled it too after a while. It never shut down or anything but the gauge read hot. Any particular thing I should check first? I've got a manual and shop manual but haven't had a chance to look at them yet.

sailingdog · #2 (**permalink**) 10-04-2007

Check the raw water strainer first... then check the raw water impeller...

dougyoung · #3 (**permalink**) 10-04-2007

If the impeller has any broken vanes. Disassemble your heat exchanger and see if the broken pieces are restricting raw water flow.

TrueBlue · #4 (**permalink**) 10-04-2007

If the strainer and pump impeller both look OK, check the exterior grate over the through-hull raw water intake for sea growth, or other water flow retrictions.

CharlieCobra · #5 (**permalink**) 10-04-2007

Thanks guys. The water up here is awful dammed cold to be checking things out on the hull.

TrueBlue · #6 (**permalink**) 10-04-2007

Is the seacock all the way open?

CharlieCobra · #7 (**permalink**) 10-04-2007

I don't know yet. This just started yesterday after a few days of running the engine with no issues.

ehmanta · #8 (**permalink**) 10-04-2007

C.C.
There are so many things that could cause this: low engine coolant, restricted raw water flow, clogged raw water strainer, oil-cooler, running at max RPM's, impeller issues, calcium build up in heat exchanger, clogged exhaust elbow, etc...
Start from the easiest and work towards more difficult. How long had you been motoring? Was this a sudden over-heat issue or was it slowly running hottter and hotter?

CharlieCobra · #9 (**permalink**) 10-05-2007

It was sudden, from one day to the next.

btrayfors · #10 (**permalink**) 10-05-2007

"It was sudden, from one day to the next."

Clogged water input or loss of coolant. Check obstructions in raw water inlet...strainer, seacock, etc. Then, check impeller. If you haven't changed it this season, do so. If there are missing rubber parts, they may be downstream somewhere, and clogging the heat exchanger, water jackets, etc. Check coolant level and be sure to use 50% antifreeze/50% water solution.

Lots of other possibilities, as mentioned, but a clogged or damaged coolant system seems most likely for a SUDDEN change in cooling performance.

Bill