Over heating Gremlin

Hello all,
This is a 2010 5.ol gxi/sx that has been perfect...untill,

This past weekend I had just left the ramp, at idle speed. Looking down at the guage I saw it was about 170 (always nailed on 150).
WTH? I shut her down and tilted up, no debris, put her back down, fired up, still rising. So I shut down again and took the manifold hoses of the thermostat. they seemed dry, Themo not opening? Took the inlet hose off the pump and blew hard having someone check the outdrive, lots of bubbles, put that hose back on, and removed the pump outlet, fired it up and a couple seconds later, lots of water. I put that hose back on and fired up again, temp started comming down and stayed at 150 all day, 44 miles worth, also when flushing out.

I'm baffeled, We didn;t see any debris in the OD inlets when I blew.
Anyone ever heard of this before? Should I change the impeller?
Any Ideas would be great thanks.

WK

Re: Over heating Gremlin

Sounds like you were sucking air somewhere. My boat had identical symptoms when I picked it up. Pretty irritating. Check your hose clamps. My issue was the old style pump that had plastic inlet/outlet tubes pressed into the metal housing. I think the newer pumps are all metal. If not, that may be your problem.

Re: Over heating Gremlin

Look at the impeller (If it's still the original, replace it). First thing you do with any overheating situation.
It's even recommended to replace the impeller yearly. Have you?

Re: Over heating Gremlin

Don S said:

Look at the impeller (If it's still the original, replace it). First thing you do with any overheating situation.
It's even recommended to replace the impeller yearly. Have you?

Click to expand...

While your at the store, buy two and keep a spare on the boat just in case...

Re: Over heating Gremlin

Thanks Guys,
Sucking air was my first thought(I left the flushing plug out one time). This pump housing is metal.
I'm sure ya'll are right about the impeller, and I'll get a spare.
It hasn't been changed, 80 hours seems awfull early, I;ll get it done.

Thanks a again,
WK

Re: Over heating Gremlin

There is more to it than just the 80 hours it's been used. It's also a 2010 or earlier pump and the impeller sits in the housing with half the vanes bent over.. Watch when you pull the old one out. Bet the vanes on the impeller stay bent over, and if they don't flex, then it doesn't pump.

Re: Over heating Gremlin

Don S said:

There is more to it than just the 80 hours it's been used. It's also a 2010 or earlier pump and the impeller sits in the housing with half the vanes bent over.. Watch when you pull the old one out. Bet the vanes on the impeller stay bent over, and if they don't flex, then it doesn't pump.

Click to expand...

Thanks Don

WK

Re: Over heating Gremlin

Update....
Changed the empeller this week. The vanes weren't stiff. They were too flexible. Each vane was cracked almost all the way down the center. None were broken. but a couple were close. Ran all day yesterday, perfect.
Thanks
DL