I have a Johnson 150 fast strike. Recently I was having a problem where it wouldn’t get about about 3000 rpm while in the water. I took the head off and found that I had scored cylinders. I took it to a shop and got it bored out and then I rebuilt the motor with .020 oversized pistons since that’s what it was bored out. After I rebuilt the motor it started right up and ran without any problems for about 45 minutes I just had it idling to try to break it in. After about 45 minutes it started to miss every once in a while and it died. Now the motor will start and it will only run for about 5 seconds and then it stalls. I noticed that the carbs have a milky white substance in the carburetor throats. I changed the gas and then took a sample of the gas entering the motor and it didn’t have any water. I checked the compression and they were all about 100psi when warmed up. And between 100 and 110 when cold. Would the 10psi cause a problem? I haven’t taken the heads off to look for any scoring again. Is there any other explanation for this problem?