1968 55hp water pump impeller test

[Buckstr]

Hi All<br /><br />I just replaced my water pump impeller and want to make sure everything is ok. I have been running it on muffs but don't see any water coming out of the exhaust relief holes. There is warm water running out of a small hole on the front (boat side) of the lower unit but not sure if that is due to water pressure from the muffs. I can keep my hands on the engine after running on muffs for 10 min and it never seems to get too warm. <br /><br />Anyone have an easy method for me to check my work and satisfy myself that I put it all back together correctly? Hate to get it out on the lake and have it overheat, not even sure the overheat light on the dash works.<br /><br />All help is greatly appreciated

 

[R.Johnson]

Re: 1968 55hp water pump impeller test

Do you have a container big enough to get the gearcase in, and deep enough to get up to the water pump? To check the hot light, disconnect the heat sensor in the cylinder head, with the key on, ground the wire going to the sensor to the engone block, the light should go on.

 

[MCM]

Re: 1968 55hp water pump impeller test

The water coming out of the pee hole is normal, after the t'stat opens you should get small stream coming out of the tell tale ports on the upper rear part of the midsection.<br /><br />I would think that after 10 min. the t'stat would have opened and it should be hot enough that you wouldn't want to put your hand on it for more than a few seconds.<br /><br />Might want to check to see if the t'stat was removed previously or that its not stuck in the open position.<br /><br />Then again how cold is it in Wyoming

 

[DHPMARINE]

Re: 1968 55hp water pump impeller test

If you were overheating,after running for 10 minutes your engine would be 'sneezing' heavily,then slow down and stop,until cooled down again.And your hand would be NO where near it.<br /><br />For accuracy,tools are available to measure temp.Best budget buy would be a 163 degree wax stick from your local dealer.<br /><br />DHP

 

[Buckstr]

Re: 1968 55hp water pump impeller test

Thanks everyone<br /><br /><br />I don't have a container big enough to test at home. MCM, I did look for the telltale ports on upper rear part of the midsection, are these the same as the exhaust relief ports? Not sure I have telltale ports on this engine. I did check the hot light and it works. Given , that it does not overheat on muffs in the driveway, I am going to risk it and take it out to the lake and see how it does. It sounds like I may have the reverse problem, and maybe it running too cold. Don't have the melt sticks nor dealer nearby so I think I will try my wifes electric cooking thermometer to check the engine temps

 

[MCM]

Re: 1968 55hp water pump impeller test

Exhaust releif ports is right. If you're running too cool check the t'stat, while you're at it may as well replace it

 

[R.Johnson]

Re: 1968 55hp water pump impeller test

I think you are OK with your water pump replacement, check it on the water for further sign's of tempature. That engine will run about 140+ degree's at idle, you can hold your hand on that for quite awhile. The wife's kitchen thermometer will not react fast enough for this test. On a 37 year old engine, I would not worry about a cold temperature sieze because the thermostat is stuck open.