Re: 1984 Johson 235 hp new head
You will want to double oil during the break-in period. Since you will not be using the factory oil injection pump that came on the engine, mix at 25 to 1 instead of the 50 to one. Factory break in is: first 10 minues-fast idle only. Next 50 minutes: do not operate over 3500 rpm. On easy planing boats-make sure the boat will plane and then reduce to half throttle. Vary the rpms frequently. Second hour: Full throttle to get on plane, then reduce to 3/4 throttle. Occasional one to two minute full throttle bursts are ok. Vary engine rpm's every 15 minutes. Next 8 hours: Avoid continuous full throttle operation for extended periods. Vary engine rpm's every 15 minutes. Do not exceed max engine rpm. Retorque cylinder heads after the break in period. As a point of reference, I'd take a compression reading before you start the break in and also after the 10 hour period.
