water pump in good shape but not pumping.....

[96baylinertrophy]

well im new this boating thing an this is my first boat, im 20 years old an could use the wisdom of much older an knowledgeable boaters. i have a 96 17 foot bayliner trophy with a 76 johnson 115, ive taken the foot off to go to replace the water pump but it all looked new an was in good shape. i know the engine has been recently rebuilt with less than 15 hours on it. it runs great with the water hose hooked to it but if i put it in a drum it runs hot quickly. i dont know why its not pumping water with a good pump in it? any help would be greatly appreciated.

 

[1946Zephyr]

Re: water pump in good shape but not pumping.....

You could probably check and make sure it's pumping, by removing the thermostat. If was gushes out where the thermostat is, then you're okay. I've seen some seize up, to where they won't open.

 

[96baylinertrophy]

Re: water pump in good shape but not pumping.....

thank you ill try that tomorrow to see when its daylight, but if the thermastat was seised shut wouldnt it still run hot while the hose is hooked up? sorry if this is a dumb question as i know very little about this.

 

[emdsapmgr]

Re: water pump in good shape but not pumping.....

Loosen the clamps on both of the large hoses which go from each head to the thermostat housing. Connect the engine to the water supply. Start the engine. Pull one hose off and check for water flow. Repeat on the other side. If you have flow, you have a restriction in the thermostat housing. That engine has one thermostat called a vernatherm. If it is stuck shut, you will overheat at idle since it won't let incoming water circulate through the block. When the engine runs normally, you will get a fine water spray mist out of the two upper midsection exhaust relief holes when the stat opens-usually a minute or so after starting.

 

[96baylinertrophy]

Re: water pump in good shape but not pumping.....

how tight should the pump impeller be cause it was very tight going in the housing an i am wondering if it might be the wrong impeller.

 

[Fl_Richard]

Re: water pump in good shape but not pumping.....

I see you removed the impeller. And yes they should be pretty tight in the housing. Did you re-install it with the little key? If there is no key installed the impeller will just slip on the shaft.

 

[raczekp1]

Re: water pump in good shape but not pumping.....

Hi.
I change the water pump imprler in my john6Hp/73y , but I wasnt sure if iput impeler in right way.Before I conect leg witch engines midsection I took bucket with water, put the leg on my engine in the bucket and conect the rod witch the driling machine(i use plastic tape to wrape around the end of the rod before i put it in the driling machine). run my driling maschine in right rotation and i could see if water is flating from water pump outlet

 

[96baylinertrophy]

Re: water pump in good shape but not pumping.....

yes i did putitback with the key in an what im pretty sure is done right but still not having the pump work think im going to replace the pump

 

[kenmyfam]

Re: water pump in good shape but not pumping.....

well im new this boating thing an this is my first boat, im 20 years old an could use the wisdom of much older an knowledgeable boaters. i have a 96 17 foot bayliner trophy with a 76 johnson 115, ive taken the foot off to go to replace the water pump but it all looked new an was in good shape. i know the engine has been recently rebuilt with less than 15 hours on it. it runs great with the water hose hooked to it but if i put it in a drum it runs hot quickly. i dont know why its not pumping water with a good pump in it? any help would be greatly appreciated.

How big is the drum ??? How are you checking the head temperatures

 

[96baylinertrophy]

Re: water pump in good shape but not pumping.....

bout 35 gallons an by touch, with the hose connected to it it can be touched but in the drum the heads heat up to much to touch, ive got to get a temp gun....

 

[Outsider]

Re: water pump in good shape but not pumping.....

.. it runs great with the water hose hooked to it but if i put it in a drum it runs hot quickly.

Drums are closed circuit with no way to shed heat. It will always end up hot without a significant water inflow.

Were the pump bad, it would heat up on the hose as well. If it runs OK there, get it and growl, you're OK as far as overheating is concerned ...