water temp problems

[RACINGdork]

howdy!
i took my boat out for a test and it wasnt pumping enough water through the engine and over heated. it was kind of spurting steam. it was alright at the start , it had a small stream. pretty much the amont we had when we had the hose connected during tuning. the she went to 120oC
if anyone has any clue your help would be appreciated
thanks matt

[kojac]

Check your supply line coming from the jet drive to the motor for obstruction. The line can get clogged from anywhere from inside the pump to the motor.
Then check your dump line to see if it is clear of debris.
You may have to remove the pump bowl and impellar to see if there is an obstruction at the pump.
Of course that includes any valves or thermostat that may be closed.
Don't run the engine until you have found the problem.
Kojac

[Duane HTP]

You can usually take an air hose to the water supply pipe inside the boat and blow backwards through it to remove something in the intake line or pump. Not a 100% deal, but more times than not, it will work if something is in the pump at that point. (just saves a lot of work)

[kojac]

Duane's right of course,
But if you have a wear ring that has the plastic liner and it has come loose or torn, blowing air back through the line may move it out of the inlet supply temporarily. But the pump pressure may push the liner over the hole again when the boat is under power.
Hopefully when you blow air through the line you find something that comes out and you can identify it.
Kojac

[Duane HTP]

That's right Kojac. It won't help a collapsed line either, but it's usually worth a try for an easy fix. It'll take care of a small rock or a stick.

[sdba069]

If your insulator has come loose, that could be the cause of the overheat even if it's not blocking the water passage. Pump doesn't pump very well when there'a a mile of clearance and the wear ring is bouncing around on the impeller.