Unsticking seized motor from storage.

chopper72

Seaman
Joined
Oct 5, 2006
Messages
51
I have a 5.5 and 4 horse from 60's that are seized from moisture. Once I get them unseized can they be started and ran?
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
50,266
depends......usually when they seize from sitting, the rings are rusted up and the cylinder walls are pitted.
 

oldboat1

Fleet Admiral
Joined
Apr 3, 2002
Messages
9,612
Tilt them on stands, and fill the cylinders with ATF or a mix of ATF and acetone. Beyond that (i.e., after freeing them up), all bets are off. Try them if you get them completely free -- turning clockwise easily by hand.
 

Chinewalker

Fleet Admiral
Joined
Aug 19, 2001
Messages
8,902
I would not recommend running a motor that has been seized without some exploratory surgery to verify that bearing surfaces haven't been rusted up. Particular care should be taken with the smaller OMCs of that era, as they have aluminum rods that are easIly bent if you torque on the flywheel or start pounding on pistons.
 

Crosbyman

Vice Admiral
Joined
Nov 5, 2006
Messages
5,655
i have had great success with a few.. incl a badly stuck 9.5 from 1966 and a 7.5 both of which work great today

steps I took

1: pull the plug oil the cyl has indicated by oldboat1 and wait couple days

2- try to turn the flywheel ..try to jar it loose if no go …..wait a few more days re oil cyl try again

3- pull the cyl head and jar the pistons with a 1 inch wood peg and hammer alternating between cyl look for flywheel movements by making a scribe or pencil mark as a referrence

4- if no go ..re-oil and wait try PB blaster or wd40 peg and hammer it again slowly but firmly till to see the flywheel move a bit ….success is close :)

5- kept at it till it loosens up and visit UTUBE

" patience brings joy"
 
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