Replacing cooling pump on a Merc 60Jet

mikesjet

Cadet
Joined
Oct 30, 2008
Messages
12
Hello everyone,

Nice to finally join, I have been lurking here and just reading. I have to say that I have read a lot of great info and some very funny and disturbing stuff ( stupid human tricks).

I had an issue with my new to me outboard, the water coming out of the tell-tale hole was just a half hearted drip when it used to be full stream. There were no warnings as I had run back down the river with it like this. I did do something really dumb though as this is my first and only boat let alone a jet outboard. I forgot that I may only need 8 inches of water on plane and 14 inches or so too float I hit the throttle and dug the stern into the bottom. I am thinking that I sucked up some dirt and sand and plugged something. I have taken the thermostat out and the hose for the tell-tale and discovered some dirt and sand but nothing that would cause me to think it was clogged. I do believe that it is just a dirt issue but having read on here some of you change your impeller every two years and sometimes sooner I am just going to pull the jet pump off and take care of business. I bought a whole pump kit ( plates, gaskets and impeller). also new thermostat. What I am asking is: I am a relative newby to outboards but have a lot of experience building auto engine and small engines, so I feel I am proficient enough to do this. Is there any tricks that I should be aware of?

Sorry for such a long drawn out post.

Thank you,

Michael
 

hamit59

Petty Officer 2nd Class
Joined
Jul 25, 2008
Messages
149
Re: Replacing cooling pump on a Merc 60Jet

Make sure your pump bearings are in good shape. If you even think there may a question about them replace them. Running in sand you need to check everything. Flush from the top down from the t -stat after you remove the lower. try to get as much sand out as you can. if it gets into the water column it could recir back into you cooling pump and trash it.
 

CharlieB

Vice Admiral
Joined
Apr 10, 2007
Messages
5,617
Re: Replacing cooling pump on a Merc 60Jet

1 a small spot of grease will hold the impeller key in place while you slide the impeller down over it

2 a teaspoon of glycerin is a great lubricant for the impeller and will stay in place however long it is before you launch the boat AND it will not degrade the impeller material

3 jet pump impeller shimming, closing/tightening the gap to the throat will lower WOT rpm, increasing gap will increase WOT rpm

4 clean jet impeller leading edges with a mill file, nice clean sharp edges carve through the water
 

mikesjet

Cadet
Joined
Oct 30, 2008
Messages
12
Re: Replacing cooling pump on a Merc 60Jet

Thanks for the info. I had already done the impeller sharpening. That is the one thing that makes me sure that the impeller was never changed in that life of this motor. The leading edges were so blunt, instead of 1/32" they were like the thickness of the blades approx. 1/4". After that it was a completely different animal. It would darn near leap out of the water in the hole shot and I gained about 2mph on the top end. It did also drop the WOT rpm down to 5100. I will be tackling this on the weekend.

Again thank you for the info.

Michael
 
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