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Jason
Jason, Marine Mechanic
Category: Boat
Satisfied Customers: 14402
Experience:  Degree in Marine Technology. Gas and diesel marine mechanic.
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2000 carver with twin 5.7 mercury marine engines, I have

Customer Question

2000 carver with twin 5.7 mercury marine engines, I have them on the dyno , and when the engine is at full throttle the timing kicks back to 20* and has low power level on both engines.......if you would like to speak directly I have a toll free number(###) ###-####thanks jimmy
Submitted: 8 months ago.
Category: Boat
Expert:  Jason replied 8 months ago.
Hi Jimmy, Jason here, have you tried disconnecting the knock sensor to see if the timing still kicks back or not? The way the ignition system work is that it will advance the timing until it hears spark knock, if it hears knock, or thinks it does because of a bad knock sensor, the timing will retard. Did you try disconnecting the knock sensors? Do you know which igniton system is on the engine?
Customer: replied 8 months ago.
hi Jason have disconnected the knock sensor and have replaced it my scanner is not detecting knock retard. it is a MEFI 3 ECU
Expert:  Jason replied 8 months ago.
Hi Alan, my name is***** transducer should remain level. What is happening is the water flowing around the transducer is turbulent, and not smooth. This causes air to get caught up in the transducer. Sonar only works in water, not air. I'm assuming there is a bracket on the back of one of the tubes that the transducer is mounted to. What you want to do is mount the transducer as low as you can on that bracket. If it is at it's lowest point already what you would do next is go to a hardware store (home depot, lowes, ace etc) and get some aluminum stock. Mount the aluminum to the bracket, and mount the transducer to the aluminum stock. The transducer will have to be pretty close to the very bottom of the pontoons tubes in order to get it out of turbulent water. Does that make sense to you?
Expert:  Jason replied 8 months ago.
Alan, my name is***** transducer should remain level. What is happening is the water flowing around the transducer is turbulent, and not smooth. This causes air to get caught up in the transducer. Sonar only works in water, not air. I'm assuming there is a bracket on the back of one of the tubes that the transducer is mounted to. What you want to do is mount the transducer as low as you can on that bracket. If it is at it's lowest point already what you would do next is go to a hardware store (home depot, lowes, ace etc) and get some aluminum stock. Mount the aluminum to the bracket, and mount the transducer to the aluminum stock. The transducer will have to be pretty close to the very bottom of the pontoons tubes in order to get it out of turbulent water. Does that all make sense to you?
Expert:  Jason replied 8 months ago.
Hi Jimmy. I'm sorry for any confusion those replies were not meant for you. Which scan tool are you using? Does the ECM still retard the timing if you leave the knock sensor disconnected?

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