HELP, I'm about to sink my boat in the middle of the lake

[gspig]

I posted last week about a fried impeller on my 165 mercruser pre-Alfa I/O. I replaced the impeller and upper housing. Went to the lake today and in less than 10 minutes, overheat again. Go home, open the lower unit, fried impeller. I get a third impeller and another upper housing. This time I try and check the entire cooling system. I run water through the water line at the gimble housing, remove the riser and watch water come out of all the water jacket outlets, put it back together and watch water come out the exhaust bellows. I investigate the water pump housing in the lower unit, no cracks, all gaskets present and in good condition. For laughs I connect the muffs to the lower case with the outdrive apart. I see water spraying out from under the pump housing. I tighten the housing until there is barely a trickle. I put the outdrive back together and put the muffs on the boat. I cannot get the engine to show any temp increase. <br /><br />I am taking the boat back to the lake in the morning. If it should overheat again, what else should I check? The POS seems fine on the muffs, why would it overheat on the lake? It didn't do this last year.

 

[tommays]

Re: HELP, I'm about to sink my boat in the middle of the lake

what are you useing for a service manual ?<br /><br />i dont see how you can fry a new inpeller that was only run with the drive in the water<br /><br />if you had to tighten the bolts on the pump again after you were done to stop leaks your not putting it together right<br /><br />it can take a long time to get up to temp on the muffs<br /><br />tommays

 

[gspig]

Re: HELP, I'm about to sink my boat in the middle of the lake

I was starting to crush the housing when the leaks stopped. Would water escaping from under the pump cause the pump to cavitate enough to fry the impeller? The pump is low enough in the drive that it should be under the water level most of the time.<br /><br />I have a Clymer manual. The first fried impeller was installed by a local shop.

 

[tommays]

Re: HELP, I'm about to sink my boat in the middle of the lake

the pump is above the cavatation plate on the drive<br /><br /> as soon as you get on plane its going to be out of the water and draw air and i would guess FRY<br /><br /><br />you have to missing a gasket or something usally the bolts only get tightened in inch pounds <br /><br /> http://mercstuff.com/waterpumpinst.htm <br /><br />take a look here and see how it matches up with what you doing the online manuals only cover and alpha i dont no how a pre is different <br /><br />tommays

 

[gspig]

Re: HELP, I'm about to sink my boat in the middle of the lake

I checked mercstuff. The Clymer's showed an O-ring and gasket under the pump. Then a gasket, steel plate and another gasket, then the upper housing. Then it shows a slinger ring on the driveshaft on top of the housing then an o-ring just below the spines on the driveshaft. All present and new.

 

[ziggy]

Re: HELP, I'm about to sink my boat in the middle of the lake

gspig, just wondering, did ya put the stainless face plate on the correct way. i think the lip faces down, per clymers. also the torque values are. back screw, 15-20 inch lbs, two middle nuts to 25-30 inch lbs. and the front nut to 35-40 inch lbs. per vol. 2 merc. service manual. water pump- mercruiser 1 thru 165 and 888, reassembly. i know ya put the hose to it. but did you look for anything blocking from the pick up slots in the lower up to the waterpump. sand? impeller pieces? believe ya should be able to look down the water pump base and see light i think.. hope ya find yer problem.......

 

[gspig]

Re: HELP, I'm about to sink my boat in the middle of the lake

Check on the face plate, pressed slopes away from the impeller. Nuts are way overtorqued, but that is what it took to stop the water spray from under the pump housing. Checked the pick-up holes and drive case for debris. I may not come home with a boat tomorrow. I guess I'll find out if the leak under the pump was the problem.

 

[Don S]

Re: HELP, I'm about to sink my boat in the middle of the lake

Nuts are way overtorqued, but that is what it took to stop the water spray from under the pump housing.

Would you mind explaining to me how you happen to see this so called "water spray from under the pump housing.".<br />I know where that pump is, and with it all put together, on the boat and running, you can't even see the pump housing let alone see water sparying from it. <br />Something doesn't make any sense here.<br />Besides, you have probably already ruined the plastic pump housings and need to buy new ones again. With that much overtorque, they are now called junk.

 

[gspig]

Re: HELP, I'm about to sink my boat in the middle of the lake

Don, I had the lower case separated from the upper and put the muffs on the lower. Turned on the water to the muffs and water was spraying from under the entire pump housing. Despite being torqued as hard as the nuts are, the overheat problem is cured.<br /><br />I now have a new problem. The boat behaves like a spun prop. Low rpm the boat moves, as I increase rpm the boat stops increasing speed. Along with that symptom there is a grinding noise like gear teeth not meshing. Noise is only at higher rpm(2000+). No reverse at all. I am hoping that the problem is in the outdrive and not a spun coupler.

 

[jeff13601]

Re: HELP, I'm about to sink my boat in the middle of the lake

I am not sure if id be hoping the problem is in the outdrive. I would rather change a coupler then have the drive rebuilt$$$$$$. I dont think it is the coupler. Are you sure you got everything back together right?

 

[gspig]

Re: HELP, I'm about to sink my boat in the middle of the lake

Checked coupler alignment and put second outdrive on. Back to the lake. I now have reverse, but same symptoms. Can move only at idle speed anything more and no speed. I'm going after the coupler next.

 

[qystan]

Re: HELP, I'm about to sink my boat in the middle of the lake

gpsig<br /><br />It looks like your engine drive coupler is bad. Its not turning the drive. With the drive not running the water impeller is not turning and there'll be no water to the engine. Take a close look/feel at the splines in the coupler.<br /><br />As for the housing, its best to change it and I wouldn't worry too much about the water leak you see with the test method you are using.<br /><br />Good luck.<br /><br />Qystan

 

[jeff13601]

Re: HELP, I'm about to sink my boat in the middle of the lake

You did try another prop to make sure the one you have is ok? It most likely is the coupler but I would check before pulling the engine

 

[gspig]

Re: HELP, I'm about to sink my boat in the middle of the lake

I've pretty much decided the coupler is bad. I did try 2 outdrive units and 2 different props. Next question is what style coupler does a '72 165 straight 6 GM motor with a pre-Alfa drive use: the mushroom shape or the triangle plate?