Overheating problem

[rockman]

First time posting, I just bought a 1990 ski nautique. I have a 1993 since 1995, I bought this one as a second boat.
I got a real good price on it. It needed lots of work, everything that was broke I fixed. The guy I bought it, said
it was running hot. I took the the thermastat out, cleaned exhaust, changed the impeller. Checked the incoming
water and it was clear. Ran it at home for 30 mins with water on and never heated up. Today I took it out
to check my work. It did over heat, my concern is, it would go to 200 when idel. As soon as I would run it to
30 mph or any speed, it would drop down to 140. It does have a heater, could the heater or water pump
or some line be partially obstructed? It has to be simple, or not. The motor has no water in it, I did clean
out the opening in the exhaust, it seams like the water may not be coming out. Any ideas, I could use
some help


Thanks Kevin

[2gofaster]

It's entirely possible that the gauge or sendor is bad.

[WakeSlayer]

First, i would verify all your hoseclamps are tight. I do this peridocally throughout the year. Use a 5/16 nut driver, not a screwdriver. It sounds like you have an air leak.
Get a laser temp gun and go over the motor when it is running on the water. Check intake, exhaust, water circ pump, RWP, etc. They are very precise and you can learn a lot about what the motor is doing with one.
Lastly, you may want to replace your thermostat. They can go bad. Should be a 143*, not an automotive stat.

[HVL2010]

Gauge issue

Rap the face of the guage with your knuckle when it is up there. It will probably drop back. I think the wiring in the dash is kinda crappy in the early 90's. Mine never overheats, but it does exactly what you are saying. I have heard that you can reground the dash to fix these issues (voltmeter moving down when you turn on more accessories) and such, but I don't really understand how to do that, so I live with it.

[NCH2oSki]

First time posting, I just bought a 1990 ski nautique. I have a 1993 since 1995, I bought this one as a second boat.
. The motor has no water in it, I did clean
out the opening in the exhaust, it seams like the water may not be coming out. Any ideas, I could use
some help


Thanks Kevin

Have you installed a new impellor? Sorry if I missed that part, check the hoses for obstructions, especially at the tranny cooler. I'm thinking its got to be something simple.

[east tx skier]

If you have a sea strainer, make sure it is tight and sealing properly.

[rockman]

Update on overheating

On my overheating with 1990 S.N/ Thanks for all that have posted replies, it all helps.
I spoke to a mechanic and he mentioned that the impeller pump has a brass fork that will
wear and cause poor water flow a idle speed. Anyone have heard this problem. Boat overheats
at idle and temp changes when speed increases. There is no thermastat in it, impeller is new and
does not leak.

[WakeSlayer]

Did you go through and check all hose clamps? And another post mentioned the strainer. The o-ring gasket is frequently a culprit. I could be wrong, but I really think you have an air leak, not a RWP problem.

Not sure why you started a new post, you should just keep the other one going.

[rockman]

Over heat

[
What do ya me RWP? I did secure all hoses and rings.
Thanks



QUOTE=WakeSlayer;133376]Did you go through and check all hose clamps? And another post mentioned the strainer. The o-ring gasket is frequently a culprit. I could be wrong, but I really think you have an air leak, not a RWP problem.

Not sure why you started a new post, you should just keep the other one going.[/QUOTE]

[KenG]

Raw Water Pump, where the impeller and "brass fork" are located.

[johnboyy7]

RWP- raw water pump. Pump that brings water in from the lake to the motor. Aka one with the empeller. When running check your strainer bowl and see if you see air bubbles.

[richard]

GT-40 over heat

Don't think new impeller is Aspirin !,my SAN had overheat problem few month ago,checked every thing: clean elbow water passage,put new impller, finally,take out the RAW on work bench,turn it with AC motor and test the water flow,,,weak !disasemble RAW I can't see any thing wrong,drop a new one the problem fix, suppose the shaft side of the pump have air leak cause low flow.

[rockman]

Rwp

I have a feeling that once I check all the lines and tranny, I will have to replace RWP, all it takes
is a small air leak or wear on pump, no flow. Where did you buy your RWP>? Cost?



QUOTE=richard;133414]Don't think new impeller is Aspirin !,my SAN had overheat problem few month ago,checked every thing: clean elbow water passage,put new impller, finally,take out the RAW on work bench,turn it with AC motor and test the water flow,,,weak !disasemble RAW I can't see any thing wrong,drop a new one the problem fix, suppose the shaft side of the pump have air leak cause low flow.[/QUOTE]

[richard]

new RAW

http://nautiqueparts.com/search.aspx?find=raw

http://www.skidim.com/prodinfo.asp?number=RA057007

[HVL2010]

Recommend buying from SKIDIM. They have always had what I needed and they provided real phone support....even when I hadn't bought something yet.