1975 '650 Merc

[DDAADDYY]

Had this thing on the shelf for a couple years and decided to throw it all together. With both Seloc and Merc manuals I completely rebuilt the powerhead. Everything seems perfect fires up in a flash, as it did before I stiored it, on a stand with the ears, good compression 120, 124, 121 top to bottom, but there is a nasty mechanical grinding sort of sound either from top piston needle bearings, top main, or upper end cap, maybe distributor bearing but I don't think so. All tolerances and clearances seemed in order and lubed up real well before reassembly. Any ireas guys, this ol' merc treated me well and I want to pass it in a good a shape as it was when I used it. Got a bigger boat and sterndrive so don't need this one anymore. Thanks in advance for your time

 

[DDAADDYY]

Re: 1975 '650 Merc

So I ripped it apart again, anyone know of a good way to effectivly pressure up the colling jacket side with the crankcase cover and crank assembly removed? I'm asking this cause lower cyl wet when I test ran it Going to have buddy at shop look at crank assembly although all bearings seem good. Whilr it's out want to check cylinder walls for leaking jackets. The exaust plate is in excellent shape so I don't think that's the culprit. Again any ideas?

 

[Plainsman]

Re: 1975 '650 Merc

You may want to Hail member ncfish1. Sorry I can't help you.