Need some help! 2000 3.0 225 EFI

[River Road]

The motor has been running fine; then all of a sudden it starts acting like I turn the ignition off and on. Does it for a split second at any rpm with no sequence. I have wiggled all the wires,kill switch, ect-no help. Today I plugged in a new harness- no help, then tried another ignition ECM-no help.Checked the fuel filters, bulb stays tight, no gradual drop in rpm like a fuel problem.I do not have a fuel ECM to try. Sure could use some help!

[hydro-cat]

What kind of spark plugs?

[River Road]

NKG 8H center fire plugs. Has anyone used the diagnostic port , would the problem show up?

[hydro-cat]

If I'm not mistaken, I think that eninge should be running Champion QL77CC. These are inductor type plugs. I just got done working on '01 225. The owner had been to the local parts store. The NGK cross, I think, was BR8HS. Which is a resior plug. Sometimes resistor plugs can play hell on ignitions. (RFI). MIght be worth a try.

[River Road]

You are right, I have a service manual, it does list QL77CC for 1997 and up. Wish that somebody was open today. History of the motor, bought it used with a smoked # 6 piston. Bored all .015 over with new pistons. It has run fine for the past 4 hours using double break-in oil. This problem just started, it just completely shuts off and on for a split second. I have been running today, it is tied up in the back yard; nothing that I have done so far Ignition ECU or a harness to the boat has helped. Thanks for the reply. Randy.

[props4u2]

Replace the shift interupt switch, it is the micro switch located on the motor where the shift cable connects to the shift lever.

Lee

[River Road]

Here was the problem, after doing everything mentioned including disconnecting the shift switch. I started changing out CDM's one at a time. Went down one row no help, changed out #1 and that was the bad one. I never thought that one bad CDM would shut down the engine and cause such a mess. Thanks for the replies.