Re: Break-in procedure
About to finally start a rebuild on a '93 Johnson 40HP, been almost a year and half torn down. Looking for a good break-in procedure, but can't easily find one here. Can someone point me in the right direction?
Thanks!
Sure thing hooli, the break in procedure for a rebuilt motor is exactly the same as the break in procedure for a new motor. The procedure can be found in the factory service model for your motor.
Here is what I do:
1. Use DOUBLE the oil for the first 10 hours of runtime. If you have oil injection on the motor then you run 50:1 in the gas tank along with the oil injection. If you don't have oil injection then you run 25:1 in the gas tank.
2. Nothing more than fast idle for first 15 minutes and vary the throttle slightly up and down.
3. Nothing over 3500 RPM for the next hour running in the water, constantly varying the throttle and rpm up and down during this period.
4. For the next hour, Use full throttle to accellerate onto a plane then back off the throttle to about 500rpm above planing speed. Again vary the throttle frequently. Never more than 10 minutes on a single throttle setting.
5. For the next hour take the motor up to full throttle for 1 to 2 minutes at a time then back down to 3500 or so for a cooling off period.
6. Avoid continuous full throttle operation for the next 10 hours and vary the throttle at least every 15 minutes.
If you used forged pistons then double the time periods above.
All the while make sure you are checking that a strong stream is coming from the tell-tale.
After the break in period pull the spark plugs and inspect them, they should all look the same. Retorque the head bolts to spec.
Cheers and good luck~!
