How do I break in outboard I just rebuilt?

[tink]

Hey guys, I'm finally finished rebuilding my '86 Johnson 40 horse outboard. I couldn't have done it without all your help. My last question for now is What is the proper way to break in my motor after I have just rebuilt it? I put new pistons and bearings in it. I am going to be taking it on a fishing trip at the end of August and want to have it ready. Thanks in advance for all your help. Tink

 

[Dhadley]

Re: How do I break in outboard I just rebuilt?

Have you identified the cause (not the effect) of the original problem?

 

[ajs584211]

Re: How do I break in outboard I just rebuilt?

Send me a fax number and I'll fax you an instuction sheet I just got from a pro rebuilder for my Johnson.<br />Basic rules seem to be:<br />check the telltale constantly <br />double oil for the first several hours <br />Under 3500 rpm for the first hour<br />get up on plane quickly so you don't tax motor.<br />vary rpm every 15 minutes or so

 

[rickdb1boat]

Re: How do I break in outboard I just rebuilt?

Did you rebuild and clean the carbs after the re-build? Why did the engine fail? Many times they fail from a lean running condition, due to clogged carbs..

 

[tink]

Re: How do I break in outboard I just rebuilt?

Well, the bottom cylinder was scored and that's why I had to rebuild it. When I took out the bottom piston, there was a bunch of crap and gunk that had accumulated in the piston rings and caused them to stick. The top piston rings could still be pushed in and they popped right back out like they should. The bottom piston rings were pushed to one side and wouldn't budge. I believe this is what caused the cylinder to become scored. I had them rebored and put in new oversize pistons, but I figured I had a dirty fuel or oil line that caused the problem or possibly had something in a gas tank at one time. Do you think it would be something else? Also, AJ, do you have an email address I could send a fax number to? Thanks again. Tink

 

[ajs584211]

Re: How do I break in outboard I just rebuilt?

Tink, Email address jsapp@necunified.com<br />AJ

 

[Dhadley]

Re: How do I break in outboard I just rebuilt?

Top rpm will have something to do with the rings coking up like that.<br /><br />Your break-in proceedure has a lot to do with the clearance that the machine shop used. I would suggest asking them if there are any special instructions on top of what the owners manual says.<br /><br />Good luck!

 

[ob]

Re: How do I break in outboard I just rebuilt?

Originally posted by Dhadley:<br /> Top rpm will have something to do with the rings coking up like that.

Heed that comment.Sound advice from a sound adviser.Insure that the engine is correctly propped.

 

[tink]

Re: How do I break in outboard I just rebuilt?

AJ, thanks a ton. I got the instructions you faxed. I really appreciate your help. Tink