Hi All,
Around 3 years ago for $200 I bought a used freshwater 4hp Johnson 4R76M which (in hindsight) probably had some bad (water in) gas. The motor ran for a few minutes, then started making a hellacious noise and then quit. At the time I really didn?t have time to work on it (my father had recently passed away, moving our mother to nursing home, etc) but now I am ready to roll up my sleeves (recently retired!) and see if I can fix it myself. I have stored the motor ?pistons up? with WD40 and 2cycle oil applied liberally through the spark plug holes. Yesterday I removed the head with only 1 bolt (left middle) that was a bit difficult to remove?due to some rust that other 5 bolts did not have. Using the rope pull start to confirm that the Flywheel should run clockwise (viewed from overhead), if I rotate the flywheel manually clockwise (starting with the Flywheel as far counterclockwise as possible, i.e. into the seized position) then I observe the following: 1) pistons are both in middle position 2) upper piston comes out/up to TopDeadCenter position 3) upper piston goes to in/down position and will not rotate clockwise any further.
Here are my questions: if I elect to try unseizing the lower piston with a stout dowel rod and light hammer taps then what position should I have the upper piston in when I tap the lower piston? Should I prelube with 50/50 TransmissionFluid/acetone? Any other tips short of full disassembly/rebuild?
There is no scoring or damage in the upper cylinder wall nor in the visible portion of the lower cylinder wall .
I know the proper/lowest-risk way to get the motor running again is to disassemble the power head, replace rings/piston/gaskets as necessary, but I am unsure that I have the time or skills to DIY. And my 2 most trustworthy mechanics have told me they?d have to charge me more than the motor is worth. So I am inclined to try quick-and-dirty, then if it doesn?t work just part-out to recover my $200. Thanks for any input.
Around 3 years ago for $200 I bought a used freshwater 4hp Johnson 4R76M which (in hindsight) probably had some bad (water in) gas. The motor ran for a few minutes, then started making a hellacious noise and then quit. At the time I really didn?t have time to work on it (my father had recently passed away, moving our mother to nursing home, etc) but now I am ready to roll up my sleeves (recently retired!) and see if I can fix it myself. I have stored the motor ?pistons up? with WD40 and 2cycle oil applied liberally through the spark plug holes. Yesterday I removed the head with only 1 bolt (left middle) that was a bit difficult to remove?due to some rust that other 5 bolts did not have. Using the rope pull start to confirm that the Flywheel should run clockwise (viewed from overhead), if I rotate the flywheel manually clockwise (starting with the Flywheel as far counterclockwise as possible, i.e. into the seized position) then I observe the following: 1) pistons are both in middle position 2) upper piston comes out/up to TopDeadCenter position 3) upper piston goes to in/down position and will not rotate clockwise any further.
Here are my questions: if I elect to try unseizing the lower piston with a stout dowel rod and light hammer taps then what position should I have the upper piston in when I tap the lower piston? Should I prelube with 50/50 TransmissionFluid/acetone? Any other tips short of full disassembly/rebuild?
There is no scoring or damage in the upper cylinder wall nor in the visible portion of the lower cylinder wall .
I know the proper/lowest-risk way to get the motor running again is to disassemble the power head, replace rings/piston/gaskets as necessary, but I am unsure that I have the time or skills to DIY. And my 2 most trustworthy mechanics have told me they?d have to charge me more than the motor is worth. So I am inclined to try quick-and-dirty, then if it doesn?t work just part-out to recover my $200. Thanks for any input.
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