Overheating 87 Merc 170

[rndcomp]

I am starting a new thread because my last one got pretty long. OK, now that I know compressions are OK (125,130,125,125) I need to focus on my overheating issue. When the engine was running on muffs at idle for about 15 minutes the oil pressure was right @ 60 psi and the temp slowly climbed to 195 degrees. It didn't go over, just stayed there. I am still seeing water coming out from front starboard side of the engine, and I have to assume that this is from a leaking front cam seal. After I shut the engine down, I wanted to check the coolant level and make sure I didn't lose it all (which may have led to the overheat in the first place), and to my surprise, I still had coolant in the riser.

So, my next question is, "Is 195 degrees to hot for a 15 minute idle on muffs?" Should I take her out to the river and see what happens?

From my limited knowledge, I figure I have one or more of the following problems:

1. Bad front cam seal
2. Bad Impeller
3. Bad Heat exchanger (clogged, cracked, etc...)

Could it be something else?

I did pressure test the coolant system with all hoses hooked up and didn't confused:see any leaks at all. I assume that is a good thing)

I also need to know if the engine is worth putting a couple hundred more dollars into to fix the overheat. I don't have enough clearance to do the front cam seal and I am a little nervous about doing the impeller since I don't have a stand for the outdrive (not have I ever taken an outdrive apart before).

Is anyone out there willing to offer some advice? I am not sure what to do.

Thanks,

 

[plassiter1]

Re: Overheating 87 Merc 170

I have the same engine and can relate to your situation

do a search of my posts to see what I mean.

cam seals and impeller need to be done.

heat exchnager might be ok.

as for is thus engine worth it? a few hundred dollars could be all it will need and the lessons learned would be worth double that.

 

[rndcomp]

Re: Overheating 87 Merc 170

Can anyone offer advice on a newbie replacing the stern drive impeller? Keep in mind that I don't have a stand for the outdrive. I am up for the challenge as long as it makes sense. Otherwise, I will have to pay someone else to do it. If so, how long of a task are we talking about. I was quoted 3-4 hours for the replacement of the front cam seal, but I don't know about the stern drive impeller.


Thanks!