Simulating full load dock side 2GM20F

[Ralph Johnstone]

Ran it a 3000 RPM today, and sure enough, my trusty laser temp probe sensed the top of the thermostat at 195 (and rising), so I backed down the RPMs. What temperature should it be?

The temp. should be in the 175 F. degree range.

I do have a red-dot heater in the loop, with valves to isolate. One thing I haven't tried is to shutoff that circulation. Not sure if that would make a difference.

An external heater would only help with the heat removal.

I'm also going to replace the radiator cap and double-check the antifreeze/water mixture.

All this before I dig into the heat exchanger.

The radiator cap and mixture would not affect the temperature unless the mix was 100% antifreeze.

All this before I dig into the heat exchanger.

I'm afraid there's only the one option left.

Waiting for the next installment in this serial.

 

[thinwater]

* Full throttle is way less than storm wind loads, and far more steady. If this even requires thought, you need to retie or find a new marina. Figure about 12 pounds/hp outboard and 20pounds/hp inboard. Not much at all, spread over several lines, perhaps a few hundred pounds each.

* The water flow shouldn't be more than a strong tide, but you could always start slowly and look around.

* There is some concern of stiring up sediment, which could clog your system. Depends on the depth and whether there are structures that result in recirculation.

* And yes, in trouble shooting a system that has missed maintenance, it is often several things. But checking one at a time is best, unless faults are obvious and need repair anyway.

I've done this many times. Often in the winter, when there is ice and no way to go out, I will run the engine at 1/2 load for 15 minutes just to clear out the fuel lines and circulate fluids. No concerns. Also for trouble shooting.

 

[mz4wheeler]

The temp. should be in the 175 F. degree range.

Waiting for the next installment in this serial.

Found the issue, and learned a few things along the way.

For all the years I've worked on engines; overhauls, boring, new rings, valve grinding, bearings and seals, I never quite understood the ramifications of antifreeze. Sure, it prevents the engine from freezing, but it ALSO greatly REDUCES the cooling capacity!

Yes, my mixture of antifreeze to water was too much! Distilled water COOLS the engine, not the antifreeze! [duh...] Seems so obvious now...

I checked with a few friends who also had the same misconception. After all, we all want whats "best" for the engine, the more the merrier! Nothing but the best I always said. Who knew the best thing to keep your engine cool was plain ole distilled water. I also learned that the anti-corrosive properties of antifreeze are inhibited UNTIL you add water.

So, from now on ONLY buy the pre-mix, and if you are in a climate where the weather/water is real warm (i.e. Bahamas), I'd (personally) mix in MORE distilled water to keep things a little extra cool.

Thanks everyone, and I hope this helps others as well.