1983 mecr 80hp

[basstracker1970]

I am working on a 1983 merc 80hp and the crank is bad so I bought one off ebay. The crankshaft I bought is from a 1975 85hp motor. I looked up the part numbers and they all seem to match. The pistions that came on the 1975 85hp have 2 rings and the pistons on my 83 80hp motor have 3 rings. Would it be ok to use the 2 ring pistons and rods on the 83 80hp motor. I wasnt sure if the 3 ring pistons would be better than 2 ring pistons. How is the 1975 85hp motor 85 hp if it has the same parts as my 80hp? Thank you all in advance for any help here. I am lost and seeking answers........

 

[Faztbullet]

Re: 1983 mecr 80hp

The 1975 85hp & 1983 80 hp both have power ported pistons. Use the 3 ringers as less age/wear on them as the 1975

 

[basstracker1970]

Re: 1983 mecr 80hp

Wouldn't the 3 ring pistons have more compression than the 2 ring pistons? Why did mercury make some pistons with 3 rings? Im sure they had a reason...

 

[basstracker1970]

Re: 1983 mecr 80hp

bump come on guys give me some input here .....

 

[Chris1956]

Re: 1983 mecr 80hp

In my experience, the three ring pistons came first. That was original on my '77 1500. When I bought replacement pistons, they were two rings.

I don't think it makes any difference which you use. You may mix as well The two-ring pistons should have keystone-shaped rings. These seal better than the rectangular rings of the three ring pistons.

 

[basstracker1970]

Re: 1983 mecr 80hp

Where can you get the keystone rings at? So your saying the 2 ring pistons with the keystone rings will have more compression than using the 3 ring pistons. I have a set of both. I want to use the pistons that will be best.........