I asked a question in another post but im reposting because I have a new issue.
I have a 2007 Chaparral with an 8,1gi engine. The other day i was coming back to the dock and running the boat quite fast. About half way the boat seemed to loose power and the speed dropped considerably. Then it just went back up close to normal speed but didnt seem to be running as smoothly. When i got into the marina, i was moving at idle speed and the boat seemed to be running quite rough. It seemed as if it was mis-firing.
I started the boat and it was running quite rough. I could also hear a knocking/ticking noise from the port side rear of the motor. I unplugged each spark plug one at a time to see if it had any effect on the engine. They all did except for the port side rearmost cylinder. I removed that spark plug and the ceramic and electrode were gone and the ground electrode was bent. All of the other plugs were fine. I was thinking perhaps a piece of carbon had broken off and hit the plug. I replaced the plug and it still runs the same.
I am going to take it out of the water today and do a compression test. Im thinking a bent or stuck valve or possibly a hole in the piston. When the boat is run, it stinks badly of gasoline and you can hear the knocking sound in the exhaust. The boat was not burning any oil or blowing any blue smoke. Hopefully removing the valve cover will show it is a bad valve in which case i can have the heads rebuilt. Im praying the broken electrode did not trash the inside of the cylinder.
My question is has anyone ever had a similar issue? Does anyone have any helpful ideas on taking the heads off or diagnosing this?
I have a 2007 Chaparral with an 8,1gi engine. The other day i was coming back to the dock and running the boat quite fast. About half way the boat seemed to loose power and the speed dropped considerably. Then it just went back up close to normal speed but didnt seem to be running as smoothly. When i got into the marina, i was moving at idle speed and the boat seemed to be running quite rough. It seemed as if it was mis-firing.
I started the boat and it was running quite rough. I could also hear a knocking/ticking noise from the port side rear of the motor. I unplugged each spark plug one at a time to see if it had any effect on the engine. They all did except for the port side rearmost cylinder. I removed that spark plug and the ceramic and electrode were gone and the ground electrode was bent. All of the other plugs were fine. I was thinking perhaps a piece of carbon had broken off and hit the plug. I replaced the plug and it still runs the same.
I am going to take it out of the water today and do a compression test. Im thinking a bent or stuck valve or possibly a hole in the piston. When the boat is run, it stinks badly of gasoline and you can hear the knocking sound in the exhaust. The boat was not burning any oil or blowing any blue smoke. Hopefully removing the valve cover will show it is a bad valve in which case i can have the heads rebuilt. Im praying the broken electrode did not trash the inside of the cylinder.
My question is has anyone ever had a similar issue? Does anyone have any helpful ideas on taking the heads off or diagnosing this?
Scott! Can you link that?...I'm cheap like that.