running johnson 90 v4 in after new pistons

[badenemy]

hey guys how long should i run the engine in for after replacing pistons and rings ive been out on the water for 13 hours but have yet to put the shetland 570 on its plain when should i start doing this.

 

[emdsapmgr]

Re: running johnson 90 v4 in after new pistons

Operate the engine at idle for first 10-15 minutes. The balance of the first hour, the recommendation is to get the engine on plane shortly after rebuilding- generally no more than 3000 rpm-half throttle. You don't want to lug the engine. Get it on plane, so it runs easily. You may need some throttle to get it on plane, but once there, throttle back so it is at half throttle. Vary the speed while on plane. Also, slow the engine down, and bring it back up on plane. During the second hour, run up to 4000 rpm, or approx 3/4 throttle. Run the engine up to full throttle for 2 minutes, then back to 3/4 throttle. Avoid continuous full throttle operation for next 8 hours. Did you double the oil during the break-in period?

 

[Dhadley]

Re: running johnson 90 v4 in after new pistons

As long as the machinist used factory clearances that's an excellent program. If he used a different clearance then he'll set the proceedure. Whoever is supplying the warranty will set the final proceedure.