[usmckao]

I'm curious if anyone knows the max range of the engine/water temp gauge is on a 1997 Mariah Shabah Z222. My boat overheated just barely above 250 degrees. If the gauge is capable of reading higher, this leads me to believe I have a bad thermostat because it may be sticking. I really hope it isn't the impeller in the drive!

[ColoradoDiablo]

250 Deg is way hot!
Normal is 160-180 deg max.
Most gauges max out on reading at 250 deg , so you could in theory be way hotter than that.

[mikeyt]

Water boils at 212f so if you are at 250f then that will certainly explain the gurgling sound you heard. I really dont think its a stuck thermostat and i do think its an impeller issue or even possibly corrosion in your exhaust manifolds.

[Brewfixer]

water may boil at 212 DegF but under pressure it will increase the boiling point. So if your thermostat fails to open at the correct temperature you can have a boiling point of >250 degF dependent on the pressure.

Take a look at your thermostat to ensure it is the correct sizing or just replace it.

[usmckao]

UPDATE.....

Took lower unit apart, impeller is in great condition, no signs of abnormal wear...Will update on thermostat in a bit.

[usmckao]

Interesting find just now...the impeller blades were fine but it appears as if the plastic bushing in which the key locks into has gotten bigger, hence the key would spin around the inside of the bushing and not lock into the grove within the bushing allowing the impeller to spin!

Crap piece o junk, probably made in China!

[ColoradoDiablo]

Good find!
Can you post a pic?

[usmckao]

Well just got it all back together with another impeller. I did place them on top of each other and there a noticeable difference in the inner diameter of the bushing. I rotated by hand to make sure that it was the issue. Bout to lube it back up and fire it up on the muffs.

[Mariah1]

What a time you have had. I can only hope it works this time.


Sent from my iPhone using Tapatalk

[usmckao]

UPDATE round 2

So the impeller I put on was an old impeller but in good shape. I tested to make sure it would spin by turning the shaft by hand. Hooked up the muffs, turned on water, fired her up. Running fine, have water exiting the exhaust, as it should. Watched temp gauge come to 175 (normal as it has been) and drop...this is showing me the thermostat was opening. Watched tstat start creeping past 175 and slowly kept on going....looked out back and guess what, no water exiting exhaust. I can't imagine on older impeller, that was completely fine when I replaced, has gone bad too.
I wouldn't think exhaust is plugged up because water was coming out.
My only guess is the older impeller just went bad all of a sudden.

Weird and at a minor loss until I order a new impeller kit and try again!