Water not pumping

[switchme]

Today my boat overheating right after starting. Temp gauge went up to 220 quickly and the warning buzzer sounded. There was no water in the impeller housing but the raw water strainer did have water in it. The impeller was replaced last fall and still looks great. My limited knowledge says either the water pump went out or the thermostat. The water pump makes no noise and all the belts are fine.

The engine is a Marine Power EFI 335 2004. Is there any way to test the thermostat?

[R&T Babich]

Sounds like you are not getting any water at all into the engine.
Make sure the line between the strainer and the raw water pump is clear and not kinked.
The raw water goes thru the V-drive cooling chamber before going to the pump.
My V-drive cooling chamber had a couple of chewing gum size pieces of cardboard in it I found when I put in a strainer.
They must have slipped thru the pickup grate then lodged in the V-drive cooler chamber.

The thermostat can be tested by placing it in a pan of water and heating it on the stove.
It should open before the water starts to boil.
A temp gauge would more accurately give the temp it opens at.

I've been trying to find a clear tube (maybe polycarbonate) to put in the raw water line to be able to see the water flowing.

[JUST-IN-TIME]

sounds like your sea-**** was closed

[ptige]

Impeller spun-out?

Same thing happened to me last year on our 2007 RZ2 with only 10 hours on a fresh impeller. After talking with John at Tige Watersports I pulled the impeller and looked to see if the brass splined insert was "spun-out" from the rubber impeller. Of course the impeller got messed up removing it with the tools at hand, but I could not spin it by hand using a screwdriver. However once I looked close I could see the brass was sticking out a little too much to one side. Sure enough, the brass insert could be pushed all the way out so it was not biting on the impeller anymore. There was no other obvious damage, and I've never seen one fail like this in 15 years. Maybe I've just been lucky, but I used to stretch my impellers 2 years. Not anymore, I'll change it every season and carry a spare.

[switchme]

Everything has been checked with no solution expect that it may be the water pump. That's the only thing not checked yet. If you bypass all the hoses & coolers and hook up water directly it works fine but that is probably just forcing water thru the system. Changed all hoses and also the impeller with no change. I guess it's down to the water pump.

[Fast1911]

Today my boat overheating right after starting. Temp gauge went up to 220 quickly and the warning buzzer sounded. There was no water in the impeller housing but the raw water strainer did have water in it. The impeller was replaced last fall and still looks great. My limited knowledge says either the water pump went out or the thermostat. The water pump makes no noise and all the belts are fine.

The engine is a Marine Power EFI 335 2004. Is there any way to test the thermostat?

did you take or change the t-stat out?

[JUST-IN-TIME]

Ok

got a sea water strainer?

the best for any cooling problem is clear hose

[chpthril]

Everything has been checked with no solution expect that it may be the water pump. That's the only thing not checked yet. If you bypass all the hoses & coolers and hook up water directly it works fine but that is probably just forcing water thru the system. Changed all hoses and also the impeller with no change. I guess it's down to the water pump.

The engine's circulation pump can only circulate water if it is brought to the engine by the raw water pump. It can not draw water from the lake, that's what the raw water pump is for. Sounds like the problem still exists in the raw water pick up system: plugged V-dive or transmission cooler, collapsed hose, etc. Stupid question but gotta ask.....is the impeller installed correctly?

[switchme]

I don't see how anything could have gotten in the hoses to plug the coolers. I've had a sea strainer on it for several years to keep anything out. The sea trainer is clear and full of water.

The impeller is installed correctly and is rotating.

If the Mech. didn't check the t-stat I'm gonna be pissed cause that should have been at the top of the list IMO.

[chpthril]

Theory of operation dictates that it is not the thermostat. Based on how fast it overheated, tells my that the block was starved for water that should be supplied by the raw water pump. A stuck thermostat would allow what water, that is in the block, to heat at a normal rate to it's normal temp. At this point, thermostat should open and allow some fresh, cool water to begin to circulate through pushing out the heated water, thus regulating the temp. A stuck thermo would allow the engine to continue to increase in temp to the point of overheating and sounding the buzzer, but the time to reach normal operating temp would be the same as with a properly functioning thermostat.

I would pull the raw water outlet hose off at the block, hook up the fake-a-lake, and fire up the engine. If the raw water system is working normal and free and clear from obstruction, you should have Old Faithful erupting within about 5 seconds of start up. This will at least divide the system in have and help narrow down where the problem lies

[R&T Babich]

... I've had a sea strainer on it for several years to keep anything out. The sea trainer is clear and full of water.
...

X2 with what chpthril said.

Is the water moving thru the raw water strainer.
Our strainer is normally full of water when the boat is out of the water.
Have you checked the raw water grate/pickup for debris?

[switchme]

Thanks for everyone's suggestions. It was the water pump which is wierd cause the old one looked just fine. Must have a small crack somewhere. With the new one it pumps water just fine.

[flyboy]

I just launched for the first ride of the season...same issue..hit max temp in about 20 seconds!

Can somone point me to a pictorial of the impeller R&R please? May as well for the water pump too! 05 Switch ci


TIA, Paul

[chpthril]

^^^ There is a procedure outlined for both the Merc and MP under the "How To" section http://www.tigeowners.com/forum/foru...aysprune=&f=47 Good luck.