3.0L '87 merc 120hp alpha1

[stug]

just bought a used '87 glasstron. Didnt notice milky oil on dipstick upon purchasing. Finally got it in the water today. The engine imediately got hot and seemed to not be pumping water. Shut down engine and returned to dock.

Where do i start to determine why im not getting coolant to engine. I think exhaust may have been coming out of the water inlets on the back. Do I need to yank the manifold off to inspect it for cracks.

Could the manifold also be my water in oil problem.

Not sure about the total history of the boat. I know it is a freshwater lake run.
If it wasnt winterized correctly what else should I be looking for?

 

[Don S]

Re: 3.0L '87 merc 120hp alpha1

When was the last time the impeller was replaced. That's the first thing you should check for an overheat problem.

 

[stug]

Re: 3.0L '87 merc 120hp alpha1

not sure PO smoozed me over on the sale said he had it out running good last season. No clue when it was.
this is my first boat, can I just disassemble where the impeller is at? I can inspect it what am I looking for? corrosion? not lubricated?

I need a diagrahm on the section if anyone has a photo

 

[Don S]

Re: 3.0L '87 merc 120hp alpha1

Here is the OEM service manual for your drive. It will explain in detail all you need to know about the impeller.

http://www.boatfix.com/merc/Servmanl/6/6covr3.pdf

Here is a link with just general Alpha information you can use with the manual.

http://www.mercstuff.com/howdoi.htm

 

[stug]

Re: 3.0L '87 merc 120hp alpha1

ty i will look into the impeller now

 

[stug]

Re: 3.0L '87 merc 120hp alpha1

bingo, ordering parts asap ty again

 

[Don S]

Re: 3.0L '87 merc 120hp alpha1

It's been run without water.
You REALLY need to find the rest of the vanes. Probably in the small tube that goes thru the transom sheild, or in the thermostat housing.

 

[4winnsskipper]

Re: 3.0L '87 merc 120hp alpha1

holy smokes, i think it's pretty safe to say your impellar is toast. also i would pull some of the smaller water lines on the engine to check for a clog from bits and pieces of that impellar going to hell, in addition to , i'd put in a new thermostat while your working on it...cheap insurance.

 

[stug]

Re: 3.0L '87 merc 120hp alpha1

ok heres a update.

Parts are instock a few towns over. Will be fixing tommorow. Got a few pointers from my fathers friend who runs a boat repair shop.

i have inspected thermostat, all hoses from outboard to intake. Did a pressure test on coolant system. I checked dipstick after pressure test, the oil level hasnt changed. there is a few small leaks on the exhaust/intake manifold on bottom side at about 12-20 psi. nothing the bilge pump cant handle every 45 minutes.

He says my best bet is to get the water pump fixed then see what happens.

I have to remount the lower section tommorow after rebuilding water pump. any pointers on alignment of stuff and lubeing certain spots to assure a cakewalk?

step 1. fix coolant issue(cheap)
step 2. run it at correct temps
step 3. stop engine and inspect dipstick every 15 minutes?
step 4. if dipstick gets overfilled fast with milky oil, Cry and dock it and yank intake and head to search for cracks