cooling problem is making my brain hurt

[piperdog]

hello,ive an old chrysler 30hp and no water seems to be getting to the engine block,.taken off bottom section ,put hose on water pipe,flows in and out the engine block ,reversed flushed ,water comes out all the relevant holes ,put bottom section back on ,start the engine ,small dribble then nothing.the impeller turns on the shaft and looks in good condition ,can it be that it doesnt ,somehow work under speed or pressure.thanks piperdog

 

[pnwboat]

Re: cooling problem is making my brain hurt

You say the impeller turns on the shaft? Are you saying that if the shaft is held still, you can turn the impeller? If so, that's your problem. The impeller should not turn independently of the shaft. It should turn with the shaft as the shaft is rotated. I'm not familiar with the 30 HP mtors, but on my 1988 125 HP motor, I have a keyway that locks the impeller onto the shaft so that they turn together. My apologies if I mis-understood you and the impeller is turning with the shaft. In this case, I would replace the impeller. I had almost no water flow. Impeller looked fine to me. I changed it and boy what a difference it made. Actually I changed the impeller and water pump housing together. One other thing to check is the water intake screen. Not sure if yours has one, but if it does, it's located just to the rear of the water pump in the lower leg cavity.

 

[bowman316]

Re: cooling problem is making my brain hurt

if water is getting into the cylinders, that means you have a bad head gasket.
is that what is happening?
Is water mixing with the fuel in the cylinders?

 

[piperdog]

Re: cooling problem is making my brain hurt

thanks for the relies ,the impeller isnt turning on the shaft and it doesnt have a head problem ,can i put a drill on the end of the shaft to test the impeller ?

 

[steelespike]

Re: cooling problem is making my brain hurt

If everything seems clear and it is not getting water with a used impreller I would try a new one.If you don't know how old it should be changed anyway.
Is the water intake clear?If you are checking it in a barrel put it in right up to the mounting bracket.

 

[gjm]

Re: cooling problem is making my brain hurt

If you are using muffs for the water supply, try using a large container and filling it up past the cavitation plate. Make sure the impeller is below water level.

 

[joho5]

Re: cooling problem is making my brain hurt

I would say you would either need a new impeller, or you might need a new water pump housing all together. If it is scored or has pits due to saltwater or sandy water activity, then that will need to be replaced. You can drop your lower unit, then attach a drill to the end of the shaft and turn your drill while the lower unit is submerged. Leave the little rubber grommet seal that the water tube inserts above the water line. See how far it shoots up in the air.

Without the tube attached, you will only probably get a bout 2-4 inches shooting up in the air...that is ok. Anything less might be questionable.

hope that helps and post your results on here.

 

[Dave K.]

Re: cooling problem is making my brain hurt

try a new impeller & as mentioned, ck the waterpump housing for scoring. also, their is a gasget under the housing that you should change as well. now, i changed my impeller this past year. the old one "looked" in great condition. the housing had NO scoring & i put a new gasget on. my heat alarm did not sound after that.

 

[additup12]

Re: cooling problem is making my brain hurt

Have you verified that the impeller isn't on upside down? if the blades are rotating in the opposite direction, there would be extremely low flow when running.