60hp Mercury Water Pump Issues

Guys I have a mid -eighties vintage 60hp Mercury on my old Cajun bassboat thats not pumping water to my satisfaction. I traded for the boat last winter and the previous owner told me I might want to put a new water pump impeller in before I used it very much. I did install the impeller and did replace the needed gaskets and o rings, and did check the stainless plate for wear and found it to be minimal so it was reused. Everything went back together ok and I started it with the cuff on. In a few seconds I had water coming from the prop hub and higher up above where the 2 ports are. I am getting nothing from the tell tale hose. I checked it to be sure it was clear by blowing thru it then by blowing into the head fitting.......nothing amiss and all clear. I cant for the life of me figure this out. I have had the boat on the water a half a dozen trips and it evidently is cooling well enough that there are no overheating problems. I ran it last time out for a half mile at 1/2 throttle with no ill effects. Its just makes me very nervous to know water is not circulating through the jackets as it should. Any ideas? TIA.

I also just checked the water line going to the fuel pump and it has a healthy stream of water coming from it with the motor running.

Run piece of wire up in the tell tale port from the outside and wiggle it around a little bit. Those telltale ports are notorious for insects building nest in the and plugging them up. Try blowing it out with compressed air after using the wire.
Sometimes it takes 2 or 3 times to get it.
Hope this solves your problem.

Just a thought,,,,did you bend the impeller vanes the correct direction???

Pulled the lower unit and took garden hose nozzle and put water pressure up in the water pipe. After a few seconds water ran out of the tell-tale just like it is supposed to. Evidently I should have replaced more than a few gaskets and the impeller as I am definitely not getting enough water pressure to the top end of the motor. I also need to check my unit against the parts diagram for all the correct parts......some jackleg may have left something out on an earlier repair attempt. Will get new pump housing and seals and try again. Also have an issue with black unburnt oily residue running down the driveshaft from the powerhead. Is there supposed to be a seal at the top end to stop this ?

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Originally Posted by dfar

Just a thought,,,,did you bend the impeller vanes the correct direction???

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Yes it goes in with a clockwise rotation.

Basically what it looks like its boiling down to is I'm getting some water flow out of the pump but not nearly what it should be.

Ric, on your oil residue. Your exhaust goes into that housing and exits out a couple of ports and thru the prop hub. That is just unburned oil in your exhaust and nothing to worry about.

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Originally Posted by cray

Ric, on your oil residue. Your exhaust goes into that housing and exits out a couple of ports and thru the prop hub. That is just unburned oil in your exhaust and nothing to worry about.

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Thanks for the tip.

The rubber seal in the outlet of the pump housing might be missing or worn out. Another cause of low water flow is the impeller being installed backwards. I usually put the impeller and key on the driveshaft first and lube the blades with some grease. the put the housing on and then Turn the drive shaft clockwise [viewed looking down at the end of the shaft] while pushing down on the pump housing.

Years back I put the impeller in the housing first, but accidentally turned the wrong way and burned up a motor.

One other thing is that sometimes I have found the copper water tube was not in the top of the pump housing outlet but had slipped over to one side during re-assembly. This can be solved by using an plastic alignment sleeve on top of the pump outlet. { Piece of garden hose about 4-1/2 inches long will work also. }
Some times when pulling the lower unit the align tube is broken or missing.

Hope this will help you out.

I agree with Cray on the oil residue.......

Yeah I installed my impeller the same way you did, put it on the shaft first, lubed the vanes then turned the driveshaft clockwise while pushing the housing down. No problems there. It was however missing the alignment sleeve but I know it went in correctly. I'm getting some output or I wouldnt be able to use the motor at all.....it would overheat. I'm going to order a complete pump and I think-hope my trouble will go away. I dont think the housing has ever been replaced, it looks old. I'm thinking the stainless cup and plate might have enough wear to be causing problems. We will see what happens when I get the new one installed.

I think you are right on with the stainless sleeve. The wear is normally not apparent to the naked eye. Just a couple thoughts. I know you have probably checked this...but there is not anything like a broken screen or something in your inlet impeding water input? Also, I know on a couple merc/mariners I have owned, the tell tale is after the thermostat. Meaning that until my thermostat opened I got little to no output. As the thermostat opened I got a good hard stream. You could actually see the stat working as the stream would psi up then down. In the hot summer it didn't take long and would really never ease up...but you could watch it in the cool weather. If by chance your thermostat wasn't working up to snuff...and your engine was plumbed this way...you would get the impression of the pump not pumping as it should. Probably not the case but thought I would throw it out there. Hope you get it figured out!! Nothing worse that losing that piece of mind on a thing like cooling or oiling.

Thermostat is exactly what I thought too until I found out these series-year model motors dont even have a thermostat. The head looks like it had a place for one but it is just a casting boss and was never machined out at the factory. But anyway thank all of you for your comments. I'll post up the results after I get the new pump installed.