I recently purchased a 1995 40HP Johnson J40ELE0D. Seller said it had extremely low hours but hadn't been used on a boat in many years. It started, ran, and shifted fine with the muffs on. Compression is 150 in both cylinders. Spark tested fine and jumped gap fine. Water pump was working great. I changed lower unit oil and plugs when I bought it.
The first time I took it out I started out with low throttle slowly increasing to full throttle. I was extremely happy for the first 2 minutes using it. We were going a full throttle pretty fast and I lowered the throttle way down to tell my dad something and when I went to throttle back up to full speed the power was extremely diminished. I would say it went from a 40hp to an 8hp at best. The gas used was brand new. I tried squeezing the gas tank primer bulb while we were driving but it didn't help. It still ran for the four days I was on vacation but never regained any power, in fact it may have lost slightly more if anything. It also still started fine but would die at very low idle occasionally. In neutral it revs up fine all the way up to full throttle but when in forward gear it has to power. The reverse gear did not seem to have a problem but I didn't test it before the problem started so I can't be sure.
After bring it home I rechecked the compression and it was still the same.Spark was still good too. The upper spark plug had some black on it and also had a very small amount of extremely fine aluminum shavings/flakes on it. It had maybe 2 or three small flakes a little smaller than a pepper flake and the rest was like aluminum dust. It was a very small amount, I was barely able to see it.
One more thing to mention. While we were on our vacation one of the guys who knows a little about motors messed with it a little. He had the motor in neutral and was spraying starter fluid in the carbs. He eventually worked it up to full throttle while in neutral while occasionally spraying in the carbs. But my point is it was in neutral and at full throttle for a good 2 minutes. I thought it was going to blow it was so loud with the carbs exposed. It didn't seem good for the motor. But anyway it didn't seem to help or hurt the performance.
Any help would be appreciated.
The boat is an Alumacraft AW 1860 MV
Thanks
The first time I took it out I started out with low throttle slowly increasing to full throttle. I was extremely happy for the first 2 minutes using it. We were going a full throttle pretty fast and I lowered the throttle way down to tell my dad something and when I went to throttle back up to full speed the power was extremely diminished. I would say it went from a 40hp to an 8hp at best. The gas used was brand new. I tried squeezing the gas tank primer bulb while we were driving but it didn't help. It still ran for the four days I was on vacation but never regained any power, in fact it may have lost slightly more if anything. It also still started fine but would die at very low idle occasionally. In neutral it revs up fine all the way up to full throttle but when in forward gear it has to power. The reverse gear did not seem to have a problem but I didn't test it before the problem started so I can't be sure.
After bring it home I rechecked the compression and it was still the same.Spark was still good too. The upper spark plug had some black on it and also had a very small amount of extremely fine aluminum shavings/flakes on it. It had maybe 2 or three small flakes a little smaller than a pepper flake and the rest was like aluminum dust. It was a very small amount, I was barely able to see it.
One more thing to mention. While we were on our vacation one of the guys who knows a little about motors messed with it a little. He had the motor in neutral and was spraying starter fluid in the carbs. He eventually worked it up to full throttle while in neutral while occasionally spraying in the carbs. But my point is it was in neutral and at full throttle for a good 2 minutes. I thought it was going to blow it was so loud with the carbs exposed. It didn't seem good for the motor. But anyway it didn't seem to help or hurt the performance.
Any help would be appreciated.
The boat is an Alumacraft AW 1860 MV
Thanks