Hello everyone here at I boats. It has been awhile since I have been here and I hope you can help!!<br />I have a 1989 Yamaha 175hp Model 175ETXG<br />The mercury switch has gone on the oil injection and I really don't want to depend on a 14 year old injection system?? I have been mixing the oil 50 to 1 in the tank most of the summer. The problem is that the plugs will foul out in about 4 to 5 trips. I asume it is because the injection mixs from 200-1 to 50-1 depending on speed. Now I do all kinds of fishing with my boat from slow troll to WOT. How Can i stop this?? I was thinking of going to a hotter plug?? I have changed from NGK to Champion and that has seemed to help a little but no were near were I should be. Champion plug is QL78C next step is a QL86C<br />Am I on the right track?? or should I fix the injection?? Any other sugesstion??<br />Thanks all!!