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1986 3.0 Mercruiser water circulation problem

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Mrpiano45

New member
Hello to all. Hopefully someone can point me in the proper direction to solve my problem. All the marinas in my NY State area are closed to my knowledge, so I need to have this problem diagnosed and maybe I can do the repair myself. The inboard runs fine, except when idling the water temp gauge rises to 170 and more whereas it used to stay constant at around 120 or so. But when I give it the gas and zip across the lake, the temp then goes back to the 120 temp. It never ran hot before when idling....just developed the problem in the past few months. To my knowledge, there is no external water pump on the inboard itself, so is there an internal pump somewhere....maybe in the outdrive? I would appreciate any assistance you might be able to give me...including any mechanics that might be available to work on it if I can't personally do the work myself. My normal guy isn't taking any new jobs right now unfortunately, he was really very skilled. I'm in the Finger Lakes Region very close to Ithaca and Watkins Glen. If you would like to email me directly, I can be reached at [email protected]. Thank you......Myles
 
3.0's typically get used in the inboard/outboard configuration, so this is for an I/O....

when was the water pump (yes, in the drive) last serviced?
 
Impeller is in the lower unit and is fairly easy to service. Not even knowing where it is ,begs the question
how mechanically adept you are with tools. Just to be clear,not following the exact procedure can lead to total drive failure . Most manuals are free or can be burned for a fee but you MUST read them.
Remove drain plugs and drain drive oil,
Shift into full fwd,remove 6 mounting nuts and remove drive DO NOT PRY , THERE ARE TRICKS
remove rear ram cylinder nuts and pin , remove trim tab, remove allen head bolt underneath trim tab, remove 2 side nuts, 2 bottom nuts under cav plate, 1 fwd nut .Total of 5 plus the allen.
, Unit should seperate, DO NOT PRY, there are some tricks for the stubborn ones.
Remove the 3 nuts and washers, the 5/16 screw , remove rubber slinger, remove upper housing,impeller, wear plate gaskets , etc.
Install impeller kit, manual shoes how
turn lower splined shaft fully clockwise while turning prop CCW untill locked,
VERIFY "QUAD RING: rubber O ring is installed in the oil passage
carefully lower upper housing making sure the brass shoes align correctly and that its facing in a straight line.
Install the 2 side nuts first then the rest
, fill from the bottom untill it comes out the top , install top plug first, then bottom one
If you need more pm a cell
 
Replace impeller in drive and thermostat which is stuck open or missing if you are running that cool. Google alpha one impeller replacement you’ll find some videos showing what DR outlines above.

Spend a few more bucks and get an OEM merc impeller kit with the plastic body. Also check your water tube in the drive for melting. If it gets hot the water won’t cool the exhaust and melt some things like exhaust shutters, and boots.

I boat out of Union Springs north of Ithaca. Lucky enough that I have squatters rights at folks place. I assumed all the public boat launches are on lock down as well?
 
Mrpiano45 said:
Thank you! I believe that I found his #. I will call him tomorrow and hopefully he can help me out. Thanks again for your help. Myles
Click to expand...

Dieter....unfortunately the phone # I found for Rick Sullivan in Union Springs (315 889-9006) just rings and rings. I actually am wondering if it's the correct # after all. Being that you're in Union Springs as well, is there anything you might be able to do to get a hold of him and give me his info? I'm sorry to have to ask you this, but I don't know where else to turn. If anyone on this forum knows Rick, maybe you could also help. Thanks in advance......Myles
 
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