‘91 merc 60hp overheating alarm buzzing

[Evinrudej]

Most Mercury had ---NO HEAD GASKET----Until the V-6 came out.-----Inline 6 never used a head gasket.

Did my model have no head gasket?

 

[racerone]

Post serial # or check the parts book for your motor.

 

[Evinrudej]

Post serial # or check the parts book for your motor.

 

[Evinrudej]

it’s not looking like it has one just connected to block no head or am I wrong ?

 

[Evinrudej]

My service manual for 100 hp range 2 stroke Mercury's says to expect problems if compression is less than 120 PSI. You're close and it may be ok but the manual says what it says!

So I had a feeling my compression tester wasn’t reading correctly. Bought a new test and tested today
(after running for 5 mins)
Top- 126
Middle- 130
Bottom-125

 

[Chris1956]

Generally speaking, compression testers are often inaccurate. However, they are usually reliable. If all the cylinders read the same (within 15%), the compression is good. I think your numbers are just fine, despite what the manual says. Is that a Merc Service manual?

 

[Texasmark]

Generally speaking, compression testers are often inaccurate. However, they are usually reliable. If all the cylinders read the same (within 15%), the compression is good. I think your numbers are just fine, despite what the manual says. Is that a Merc Service manual?

Mine is.

 

[Evinrudej]

So I had a feeling my compression tester wasn’t reading correctly. Bought a new test and tested today
(after running for 5 mins)
Top- 126
Middle- 130
Bottom-125

So it just occurred to me that I messed up and put that these numbers were after running when in fact they were before running dry cylinder. After running it my numbers were 127 top 131 middle 131 bottom. Seems fine to me.

 

[Evinrudej]

So it just occurred to me that when I changed the impeller I did more of a quick job and just replaced the impeller and left the current impeller plate gaskets on because I was really just trying to trouble shoot the issue. Pumps water great but if one of the seals is leaking could this
lead to water in the gear case or damage to the bearing below the impeller plate? Gaskets looked completely original. Just replaced impeller safe to leave it like that?

 

[Texasmark]

Ask Faztbullet. I recall on an impeller replacement question he mentioned that you needed to ensure that the silicon (gell formed) seal, somewhere in that area, needed to be inspected and updated if needed: "To keep water from..........................." I forget the verbiage but that is something to check out....if your engine uses that sealing routine or it its just on some newer year-model engines.

 

[airshot]

Is that motor oil injected ?

 

[Texasmark]

I’m going to replace the impeller and thermostat and start there. Problem is I’ve had this boat out a few times so how can I also check for damage besides a compression test?

Well, I would see if it met my expectations.....starting ability, idling ability, acceptance of fuel to get on plane in a short amount of time, top speed in an area where other boats of same construction run. If I does all that then what are you looking for? Would seem to me that nothing is wrong with it.