I have a 25' commercial boat with a Chrysler 360. It was my father's boat. The engine is about 20 years old. It rarely saw over 2000 rpms, had so-so maintenance. So it probably had some sludge.
Last fall the fuel pump went up. On a marine engine the fuel pump bypass dumps gas into the carb. I had it towed into the marina. I did not know the fuel pump went (and did not shut off the fuel line). I came back next weekend and the entire motor was flooded with gas (intake, cylinders, and crank case).
So basically my entire motor was flushed with gas through the carb.
I turned off the fuel, pulled the spark plugs and hand-turned the motor to clear the intake and cylinders. I then pumped out the crank gas/oil mixture. I replaced the fuel pump, added oil and a new oil filter.
I ran the motor maybe 3 minutes. The oil looked like dirty and thin, honey.
I changed the oil and filter again. I added crankcase stabilizer and ran for 5 minutes, fogged the motor, flushed the raw water system with RV antifreeze, etc. The oil looked OK. The motor was winterized.
I'm ready to put her back into the water. How many more times should I change the oil and how many hours? Should I consider Auto-Rx?
I was thinking:
1st oil and filter change at 10 minutes.
2nd change at 30 minutes(1st time at operating temp, evaporate any fuel remaining)
3rd after 1 more hour, then back to normal changes.
Last fall the fuel pump went up. On a marine engine the fuel pump bypass dumps gas into the carb. I had it towed into the marina. I did not know the fuel pump went (and did not shut off the fuel line). I came back next weekend and the entire motor was flooded with gas (intake, cylinders, and crank case).
So basically my entire motor was flushed with gas through the carb.
I turned off the fuel, pulled the spark plugs and hand-turned the motor to clear the intake and cylinders. I then pumped out the crank gas/oil mixture. I replaced the fuel pump, added oil and a new oil filter.
I ran the motor maybe 3 minutes. The oil looked like dirty and thin, honey.
I changed the oil and filter again. I added crankcase stabilizer and ran for 5 minutes, fogged the motor, flushed the raw water system with RV antifreeze, etc. The oil looked OK. The motor was winterized.
I'm ready to put her back into the water. How many more times should I change the oil and how many hours? Should I consider Auto-Rx?
I was thinking:
1st oil and filter change at 10 minutes.
2nd change at 30 minutes(1st time at operating temp, evaporate any fuel remaining)
3rd after 1 more hour, then back to normal changes.