What caused failure?

Hooli

Seaman Apprentice
Joined
Jul 16, 2008
Messages
44
Ok, I have my '93 Johnson 40 torn down and ready for the machine shop. While they are doing that, I still have to determine what happened. The motor had been sitting for about a year and a half. I cleared the fuel lines and carb bowls, and drained the gas tank. Fresh fuel, and ran it. #2 scored on me after about 8 miles of driving. Cylinder and crank were DRY. I pulled the carb apart looking for an obvious obstruction and found none. Now I am nervous. If I can't find the problem I am not real comfortable running it again. Also, can I replace the rod bearings without the main bearings? Being #2 went dry, the lube on the rod bearing wasn't there either, I feel like I ought to replace them but a whole bearing kit is more than I want to do. Thanks.
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: What caused failure?

clogged jets in the lower carb. did not deliver fuel/oil.
 

CharlieB

Vice Admiral
Joined
Apr 10, 2007
Messages
5,617
Re: What caused failure?

What does the crank look like?

Are you replacing the rod?
 

Hooli

Seaman Apprentice
Joined
Jul 16, 2008
Messages
44
Re: What caused failure?

Both rods and crank looks and feels fine, real smooth. No, I see no reason to replace the rod. So rod bearings ok?
 

wilde1j

Vice Admiral
Joined
Apr 15, 2002
Messages
5,964
Re: What caused failure?

Make certain you're sure of the failure cause, or it certainly will happen again.
 

SKEETR

Chief Petty Officer
Joined
May 3, 2008
Messages
430
Re: What caused failure?

Clean the rod bearings well and inspect the rollers with a magnifying glass look for pits or cracks. Chuck em if they look blue at all. Same with piston neddles. I would at least buy new pistons and wrist pins as well as rings of course.
 
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