575SCI's, Thermostats and high temp alarm.
 

Wondering if others with modified 575SCI's have removed their thermostats to keep water temps down?

Now that we are deep into the season up here, our lake temps are in the 80's, My ECM's have been re-programmed for 120 degree T-Stats but after a long hard run, (5650, 7lbs boost) temps will climb high enough for the temp alarm to go off so I pull back until the alarm shuts off and all is well again. If I'm just cruising, no boost, temps are normal. When the lake temp is cooler, Spring/Fall, I do not have this problem.

The fact that a blower motor is fitted with a thermostat just does no sit well as you always want as much cool water to the heads as possible. I'm wondering if I can have the ECM re-programmed to not run a thermostat at all to keep temps down. Can the MEFI 3 system function properly with cold water temp? Thanks in advance. Kurt

-Also, both sea pumps are replaced. This is not a new problem, happens every season once lake temps creep up.

Mines be running about 150* too. One will run about 150* at cruise, then creep up when running hard. The other seems to stay around 130* at cruise, then creep up when running hard. 8 lbs water pressure average at cruise (which is same as with new sea pumps).

I'm going to put some new sea pumps on it this week and see what happens.

I'm working on one that is turned up a bit and can't make them run cool either. Water pressure on both motors is kinda low. What are you guys seeing for water pressure?

My water pressure is 10 lbs wot. Has always been that way

What temp is it at that your alarm is going off?

That seems awfully low Kurt. My engines, while custom, cruise at 12psi around 3000rpm, 18 psi at 4000, and 25psi at 5500+. Thats with a transom mounted water pickup, no T stats. Water temp never comes off the 100 deg mark no matter how long I hold it.

How hot does your oil get? Maybe some mods to get more water in at the pickup? You running intercoolers off the system?

I have never had my temp alarm go off with stock or 120 stats. Of course most of the time I was running an imco lower with huge pickup.

Yeah, I think water pressure should be higher but that's the way it has always been. Oil temps are normal, runs about 220 wide open. They have the factory Merc Racing thermostats. Intercoolers are plumbed with separate transom mount pick-ups. Lowers are Sportmasters, wondering if they just don't flow that well at speed.

About 175 -Gaffrig gages.

I don't have chillers, but have the AZSM kit (120* thermostat and small pulley) - minus the tune that Eddie Young did over the winter. I'm now running roller cam, as well. When I first got it back from him, water pressure was much better than it is now and temps stayed around 125* on both motors (and that was with old sea pumps). But over the course of the summer, the water pressure has regressed a little and temps have increased. Eddie also put in plugs in the top 2 holes on the DWP drive and scalloped the lower holes to grab more water, and I also have nose cones installed.

At cruise speed (3200 rpm), I'm at about 6 pounds, at 5000 rpm I think I'm around 13 pounds.

If anyone has any tips to get water pressure up, I'd love to hear it. I probably should have just put pickups in it while the motors were out.