rebuild break-in period

[digtech]

I'm two hours into the recommended ten hour break-in period on my 40hp Johnson 2 stroke since rebuilding it. I don't have a tach on my engine, so would it be okay to run at wot for a second or two just to see where it is? It's kind of hard to gauge where 3/4 throttle is, which is as far as I'm supposed to go. Also, could some one tell me, in technical terms, exactly what is happening internally during this break-in period?

 

[ob]

Re: rebuild break-in period

GA.Dave, If you have clocked 2 hrs on your engine since rebuild it is acceptable to run engine to WOT for brief periods not to exceed several seconds and then backing off to lower rpms.It is advisable to vary rpms even from low to midrange during the break-in procedure .The primary reason to take it easy on the engine during this critical break-in period is to allow the piston rings to seat in to the cylinder walls.Once properly seated they more efficiently distribute the lubricant in the fuel to the cylinder walls.This break-in period also gives time for the con-rod and main bearings to wear in and run more friction free.