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View Full Version : 1989 Prostar running 180 degrees - too warm?


LotusV8
06-30-2012, 07:16 AM
All,

My 1989 Prostar 190 with Indmar 351 is consistantly running 175 - 180 degrees, this just seems a little high to me.

What is normal operating temp for this model?

Thanks in advance for any feedback on this subject.

lhkrueger
06-30-2012, 08:29 AM
My 83 power slot 351 runs right at 180. A low engine temp results in poor fuel atomization and fouled plugs.

03geetee
06-30-2012, 10:20 AM
My exact same boat runs at 140, weird. I have the stock temp thermostat which I think is 143 degrees.

Interesting.

JTR

j.mccreight@hotmail.com
06-30-2012, 10:38 AM
All,

My 1989 Prostar 190 with Indmar 351 is consistantly running 175 - 180 degrees, this just seems a little high to me.

What is normal operating temp for this model?

Thanks in advance for any feedback on this subject.

you should have a 160 thermostat, most likely a 180 has been popped in there, 180 is not overheating...

LotusV8
06-30-2012, 07:30 PM
Guys,

Thanks very much for the information, I will replace the thermostat.

Playing hookie Prostar 190
07-12-2012, 09:19 AM
My 89 runs usually just over 160 in the summer time on a bath tub warm lake, but lately with the amount of weeds on my lake I have seen the temp rise to 180 and alittle over. I have found weeds blocking the transmission in line cooler this restricts water flow to the rubber impeller and causes slight overheating. Follow the rear hose out of the hull near prop shaft remove from upper part of trans cooler and check for debris. dont use a sharp object to clean may dammage trans cooler .If this area is clear no debris found you will next need to check the rubber impeller and the thermastat. (mine from the factory was 143 deg) thats what is in there again now.

imracin68j
07-13-2012, 12:32 AM
180 is cold and wears the motor out more. If you're boat ran 190 your parts will last longer. A racecar makes maximum HP at around 210-220 which tells you the friction lessens at the higher temps. My racecar gets up to 250 sometimes on the track and that's hot as hell but at the end of the year the bearing look like new. I would add 1 bottle of lucas assembly lube to your oil. They have 3 oz bottles. it's filled with zinc, something the hippies took out of oil a few years ago to pass smog. It's what protects engines against friction. You can also use VR1 valvoline. my boat gets up to 180, I'm thinking of putting a 190 in it.

thatsmrmastercraft
07-13-2012, 12:37 AM
180 is cold and wears the motor out more. If you're boat ran 190 your parts will last longer. A racecar makes maximum HP at around 210-220 which tells you the friction lessens at the higher temps. My racecar gets up to 250 sometimes on the track and that's hot as hell but at the end of the year the bearing look like new. I would add 1 bottle of lucas assembly lube to your oil. They have 3 oz bottles. it's filled with zinc, something the hippies took out of oil a few years ago to pass smog. It's what protects engines against friction. You can also use VR1 valvoline.

Cold for an automotive application, but warm for a marine engine. Manufacturers sure go to extremes to keep these marine engines running cool - especially the older engines. Low compression, mild cams, small carbs and mild timing sure made room for modern engines to produce more hp.

imracin68j
07-13-2012, 01:48 AM
oil is oil and protects metal the same at any given temp. colder oil = more friction. More friction = more metal being removed. It's probably why marine engines get yanked at a few thousand hours compared to a car which runs more like 100,000 hours.

cscook
07-14-2012, 09:55 PM
I would be surprised to see any car engine run that long. 300,000 miles would be alot for an engine, figure an average of 60 mph, that gives you about 5,000 hours on the engine of that car which I think is a high estimate of the number of hours you can expect out of an engine before you need a new one.

petermegan
07-14-2012, 11:44 PM
My computer in my cars always show an average of 35mph so double that to 10,000hrs maybe. I agree that a bit warmer shouldn't hurt your motor.

imracin68j
07-16-2012, 12:59 AM
I ran my race engine last night at 230 at 7800 rpm. The bearings will look like new at the end of the year. We beat the snot out of the cam and lifters and the rings are pounded with higher compression. Engine builders get uptight when racers don't let their motors get to 190 before turning them loose.

FrankSchwab
07-16-2012, 03:20 AM
The problem with temperature in a boat engine isn't wear, or lubrication, as I understand it. It's purely to prevent deposits in the cooling system.

When you fill up your race engine, you probably use distilled water and coolant. When you're pumping lake water through the heads/block, there's a lot of dissolved calcium and other solids that will precipitate out at temperature. The original poster has a 20 year old engine that's had conceivably a million gallons of hard, dirty water run through the cooling system - that's a lot of potential deposits.

Besides, remember that in your race engine, the cooling system is under pressure. If you tried to run a fresh water cooled engine at 220 degrees, the water is all going to turn to steam, which won't do squat for cooling things further downstream in the engine.

Yes, it would be better to run the engine at higher speed - you get better efficiency, and the engine would be perfectly happy. My Explorer had a 195 degree thermostat for precisely this reason, and ran 180,000 miles before the A/C died and I sold it - with a tight, dry, perfectly running engine.

But my boat has a 180 degree, and I don't feel a need to go above there. Older ones came by default with 160, and had the carb/timing/cam tuning to do as good as they could at that temperature.

/frank

MikeyOrange88
07-16-2012, 08:45 AM
My '88 Tristar 351 runs more like 150 or so, pretty consistently.
I'd go for an impellor replacement.

tph
07-16-2012, 12:58 PM
My exact same boat runs at 140, weird. I have the stock temp thermostat which I think is 143 degrees.

Interesting.

JTR

And my '83 runs 160 degrees all day long. That is strange!