1974 115hp Johnson

[GlasstronJim]

I was wondering can I rering 2 cylinders on this motor,without doing the other side. The good side has 115-120 comp. The bad side has 75-85. And which manual is the most user freindly? Thanks Jim

 

[Joe Reeves]

Re: 1974 115hp Johnson

The most friendly service manual would be the factory OMC manual.

The engine has to be torn down completely to re-ring those two cylinders, and I assume that machine work will also be needed. Meaning that everything will be removed from the crankcase (block). Two more sets of rings wouldn't be that much of an added expense and it is highly recommended that you install new rings throughout.

 

[GlasstronJim]

Re: 1974 115hp Johnson

Thanks Joe

 

[crb478]

Re: 1974 115hp Johnson

Are you sure that it needs to have new rings? Have you tried the head gaskets or torn it down to see. Joe Reeves will not steer you wrong, but what testing have you done to diagnois the problem? You only mentioned the compression numbers. The origional Johnson manual is the one you want. You can usually find one on e-bay without too long a wait.

 

[Benny1963]

Re: 1974 115hp Johnson

if the motor is running try a decarb see if it brings those numbers up
you could have several things leadig to those numbers . if they are still low
pull heads and ex cover to see what kind if damage you may have go from there those numbers are low and not very equl but you may have a couple of issue you can deal with before you have to taear down.
good luck bennyb

 

[Gary H NC]

Re: 1974 115hp Johnson

Here is a real OMC service manual,the best money you will spend..
They are hard to find but the seller has one left..
http://cgi.ebay.com/ebaymotors/1974...62QQcategoryZ26453QQihZ010QQitemZ200065005413

 

[ezeke]

Re: 1974 115hp Johnson

Great deal unless you get it for half that price because it's used.. http://cgi.ebay.com/ebaymotors/John...4547495QQcmdZViewItem?_trksid=p3286.m20.l1116

BTW, that's a little unusual to find both holes bad on the same bank. I would check the head gasket and the cylinder head.

 

[Joe Reeves]

Re: 1974 115hp Johnson

I agree with all of the above that before tearing the powerhead down to first remove the cylinder head to inspect the head gasket, cylinder walls etc.