I have a 1989 Evinrude 150 on my bass boat. It has progressively lost power for about a year now. But still, on rare occasions when the outside air is cold, it will run as good as new. When running correctly, it can get up to around 53 mph, but now it is only getting to about 37 mph and only turning 3500 rpm. It is also using a lot of fuel. I think it may be the power pack, but I don’t want to start just replacing parts without a little more investigation. On crank up, it seems like the QuickStart runs too long and every time you crank up afterwards, it idles high for +\~ 2 minutes before it idles down. All the cylinders are getting fire, but it seems like the left bank may be getting more than the right. I have old power pack that may or may not be any good, and when I put it on, it runs about the same on muffs at the house. I have also attached a video of it idling on muffs. Any ideas would be greatly appreciated. Thank you