I bought this motor last summer with 498 hours on it. It ran really good when I got it but with in the first could hours of use I had cylinder #4 drop down too 85 psi with all other at 125.
I rebuilt the motor my self. All 6 cylinders were bored 0.20 over and had 6 new Wesico pistons and rings installed. The build went simple. No problems going back together or during install. Took the motor our the first time yesterday. I used the shop manual procedure #1 to purge the oiler system. Also, I also ran a small can of premix through the motor for start up. The motor fired right on with in the first couple seconds of turning that key. (123 psi all around)
Took the boat out yesterday. Everything was a smooth as good. The boat planed right up and seemed to have tons of power. I cruised for about 15 minutes down lake at 3,500 rpms varying at times. Stopping and starting back on occasions as my son was fishing a few spots. Each time it was perfect. It was smoking pretty good which i felt was a good thing.
Eventually as I was cruising I sensed that the motor had lost some power. I slowed down to a stop and it would not get on plane after that. It seemed like it was running on 3 or 4 cylinders all though it sounded normal. Pulled into a dock and pulled the cowl. The oiler seemed to be fine. The block was warm. I couldn't hold hand on it really long. It didn't seem "HOT"...just really warm. I got pulled into the Marina and checked compression. 113 all around on all 6 (motor had cooled for a couple hours)
I haven't checked yet but, I'm assuming that the head bolts "may" have loosened a little bit. But it seems that everything is the same. This is still in the upper end of the spec so I assume all is well.
I know this engine has the Engine Guardian system on it.
Sitting in Neutral the motor will start to miss around 3,000 RPM. All plugs look similar.
Where should I start to look for a problem?
I'll check for spark on all 6. Other than that where else should I look?
I rebuilt the motor my self. All 6 cylinders were bored 0.20 over and had 6 new Wesico pistons and rings installed. The build went simple. No problems going back together or during install. Took the motor our the first time yesterday. I used the shop manual procedure #1 to purge the oiler system. Also, I also ran a small can of premix through the motor for start up. The motor fired right on with in the first couple seconds of turning that key. (123 psi all around)
Took the boat out yesterday. Everything was a smooth as good. The boat planed right up and seemed to have tons of power. I cruised for about 15 minutes down lake at 3,500 rpms varying at times. Stopping and starting back on occasions as my son was fishing a few spots. Each time it was perfect. It was smoking pretty good which i felt was a good thing.
Eventually as I was cruising I sensed that the motor had lost some power. I slowed down to a stop and it would not get on plane after that. It seemed like it was running on 3 or 4 cylinders all though it sounded normal. Pulled into a dock and pulled the cowl. The oiler seemed to be fine. The block was warm. I couldn't hold hand on it really long. It didn't seem "HOT"...just really warm. I got pulled into the Marina and checked compression. 113 all around on all 6 (motor had cooled for a couple hours)
I haven't checked yet but, I'm assuming that the head bolts "may" have loosened a little bit. But it seems that everything is the same. This is still in the upper end of the spec so I assume all is well.
I know this engine has the Engine Guardian system on it.
Sitting in Neutral the motor will start to miss around 3,000 RPM. All plugs look similar.
Where should I start to look for a problem?
I'll check for spark on all 6. Other than that where else should I look?