Hello,<br /><br />I have a 1984 Johnson GT 150 that went bad on my father a few weeks ago. He said it was running fine then started losing power until it died and then would not start as if the battery was dead--it was locked up I am sure. He finally got it started and limped it home with the warning buzzer going off. <br /><br />Short story result is a burnt #3 Piston and scored cylinder but my question is why? Strangely I do not think it a VRO failure-which I will remove during rebuild--as none of the other cylinders were damaged. The #3 piston melted and erroded as if it was suffering bad preignition which it may have been if it got really hot due to some other cause. I plan to check the cooling system too but saw no paint discoloration to suggest overheating and he said it was pumping when he started off on his doomed journey.<br /><br />Should I be looking at the powerpacks/ignition to see if it was bad timing on this one cylinder that caused the burnt piston? Has anyone seen this before? What is the best way to check this type of ignition? Or is all of this wrong and I am just another victim of a VRO failure? I plan to rebuild the power head but want to know the root cause first. Thanks for any help.
