G-Force

Engines runs fine at low/mid range speeds but temps really climbs when I hit the throttles hard.

Thermostats had been drilled (1 hole) but that didn't help.
Took the guts out of the thermostats and that seems to have solved the problem but now I don't have decent engine temps.
Is there a high volume thermostat out there - or maybe another cure?

Engines are 502's with crossovers...

Smitty

iTrader: (1)

G-

What temps are you seeing at W/O ?? My boat runs at only around 120 degrees after a hard run when it is 80 degrees outside.

Are your sea pumps new/rebuilt ??? It sounds like you have enough flow if the temp drops when the t-stat is out. You might need to find a happy medium with a restrictor plate in place of the t-stat.

Have you checked the oil temp when the water temp is hot??? Your oil coolers might not be sufficient enough.

Also check your timing. If it has too much advance it will run hotter. I believe you want a max of around 34 degrees from 3000 rpm to redline. Timing too far advanced will also drive up oil temps.

Later Bro--

Dennis Moore

This is usually a result of the water pickup sucking air at high speeds. Is your boat so fast that it needs a low water pickup? Is there something on the boat bottom adding air to the water that is passing by your intake?
Sincerely
Dennis Moore

G-Force

We backed off after 160+ degrees with no sign of the needle slowing down.
Everything on the engines are brand spanking new.

Now running 105 without T-stats.

Definitely thinking the T-stat is too restrictive - could go with an automotive one but really don't want to be changing them every year when the finally start sticking.

I'll have to see what oil temp I'm running - using straight 40 weight Schaffer (sp?) and have great pressure.

See ya! Matter of fact....I'm leaving the office in 20 minutes to go tool around and waste some gas on the boat. Today and tomorrow....in the 80's. After that....brrrrrrrrrr.

Wally

iTrader: (1)

hey G, what temp thermostats do you have in there? Also is the oil cooler or if you have a powersteering cooler too small? maybe that restricting the water flow at higher speeds? How about the intake hoses? are they new as well? maybe they are colapsing on high rpm's due to vacume from the sea water pumps?

cuda

Do you have sea strainers? They may be filled.

Gary Anderson

Check your water hose too, pickup to the water pump. It could be collapsing internally.
Gary

BadDog

Arizona Speed and Marine have the high flow T-stats. I bought some 120's. I think they have 140 as well.

BadDog

Just another thought, my 502 would use oil to the tune of 1 qt per 5 hours on some trips. Other times I could go 5 and not use a drop under similar conditions. Once the 120 t-stat was installed oil consumption has gone to maybe 1/2 quart in 10 hours. I am running the 120 because of the blower. Oil consumption never really changed even with the addition of the blower.

Panther

I see the engines are new, but is the boat and drives old?

I have seen the water hose from the transom assembly to the bell housing collapse at high speed. I have also seen salt build up where the water hose attaches to the transom assembly reducing flow.