GT40 Temp at 120 Thermostat Replacement

[ricofrancois]

Hi

I noticed the temp on my 1997 Ski Nautique 196 GT40 is hardly moving between just under 120 to just above.

Feeling the thermostat temp on the engine, it is fairly cold and does feel like 120, even after having a few ski runs.

I also noticed a lot of smoke when starting a skier which suggest the engine is running too rich.

I was thinking the thermostat may be dead and needs to be replaced. I ordered the 160 thermostat from Whitelake and will replace next week end.

Do you know which tool are required. I think there are 2 bolts to remove but what size are they?

Any help appreciated.

Eric

[SBRS]

You will need a flat head screwdriver to remove the three hose clamps and a 1/4 allen wrench / hex key to remove the two allen bolts.

[ricofrancois]

Thanks, that's helpful. Any tip on changing the thermostat? Is the gasket included by Whitelake enough?

[SBRS]

The two surfaces the gasket touches may need to be cleaned. A putty knife will work. If White Lake is selling you PCM part # RP026002 (160 degree) or RP026002E (143 degree) the thermostat comes with the gasket.

[WakeSlayer]

FWIW, You should use a 5/16" nut driver, not a flathead screwdriver. You get a better torque on it, and you will bleed less. Assuming your 97 has EFI, you want the 160* stat. If it is carbed, 143*.

[ricofrancois]

Thanks. it is EFI so I ordered the 160.

[NCH2oSki]

You should also note the orientation of the cone shaped part of the thermostat, and make sure you put it back like it was. I dont know which way is correct, but I'm sure I was the first one to change mine so it went back exactly the same.

[jjgag60]

Burning rich

To really tell if you are running rich, look at the spark plugs. They should be paper brown bag in color. If they are black or oily looking, then you are running rich. The Gt-40 with the EFI burns really clean, all most on the lean side.
You can also buy one of those hand held laser temp tester to make sure everything is running cool and it is not just your dial reading wrong. Good luck

[WakeSlayer]

Good advice on the orientation of the stat. To my surprise, the Mustang did not have one in it when I first got it. I inadvertantly installed it backwards. They don't work too good like that.

Also agree on the handheld laser temp gun. They are a great, must have tool. I like the Ray-Tek ones, they are cheap on Amazon.

[ricofrancois]

I replaced the thermostat on sunday and the old one was stuck open. I can't even close it by hand. I put the new one in with the new gasket. The old gasket was really hard to remove, I had to use blades to strip it clean. the temp is now just above 150 with lake water at 55. The GT40 EFI sounds much better, the throttle is more responsive with no hesitation and when starting a skier, no more gas smell. It's amazing what $15 part and 30min work can do!

Thanks for all the tips.

E

[bhectus]

good info here, my '96 has the same symptoms, now i have a head start on what to try first!

[TimF]

Thermostat gasket leaking

Can someone help me with the t-stat. 1993 Ski Nautique. I replaced my thermostat and did not look at the orientation of the cone part. Does anyone know what is the correct direction? Also, Does the thermostat go in first and sit in the indentation and then put the gasket over or does the gasket go down first and thermostat over the top? This will push part of the gasket down with it as you tighten down the housing. The one that I took out looks like the later orientation and thats what I did. The housing is now leaking and won't seal.
Thanks,
Tim

[DanielC]

The thermostat sits in the groove. if a slight amount of water leaks around the thermostat outside diameter, no big deal. If water leaks out of the thermostat housing, you have a water leak.

[bhectus]

the tstat goes in first in the little groove. Then the gasket goes on over top. The gasket is to seal the upper and lower housing. If you have a leak you either a.) didn't properly clean all the old gasket material off before putting new one one, or b.) put the gasket and tstat back in incorrectly.

[PatrickT2]

Eric,

I have the same engine and am experiencing the same issues this year. I'm guessing I'll find the thermostat where the water intake hose connects to the engine?

Any other tips than those listed above? Want to make sure I take the right tools with me to the lake.

Thanks,

Tom