Loss of Power, Mercruiser MX 6.2 MPI

[brewmoody]

Any ideas re loss of power in both engines approaching 1600 rpm? Get an audible alarm, but gauges read fine. When this occurs, both engines experience loss of power. They both run good under 1600 rpm, but once the loss of power occurs at 1600, you have to idle back and put in neutral and then back in gear to proceed. Thanks in advance.

 

[alldodge]

Howdy

Check you neutral gear switch on the shift plate. If its out of adjustment the ECM things its in neutral and doesn't let you go above 1600

 

[achris]

And it does it on both engines becuase their ECUs are hooked together. If one experiences a problem that requires the engine power to be limited, then both engines get limited. TEMPORARILY disconnect the connection bewteen them to isolate the engine that is going into Guardian mode.

Chris.........

 

[brewmoody]

Thanks for the responses. Appreciate the advice and I'll try this weekend.
Chris, I'm not sure how to disconnect the ECU's. Can you advise?
Thanks again,
Bob

 

[brewmoody]

Checked the transmission and there is no gear switch or shift interrupter. This is a straight inboard, 2007 model year coupled to the original gear (1983). The transmission wiring harness has a four pins and nothing is connected to the transmission side. I should have mentioned this is a friend's boat that he just purchased, so I (nor he) know anything of the history prior to his purchase.

 

[alldodge]

The transmission wiring harness has a four pins and nothing is connected to the transmission side

OK, its an inboard
There is a 4 pin harness and nothing is connected to either transmission?

 

[achris]

I believe the engines are connected to each other through the CANbus link. Disconnect the link and the engine stop knowing what the other is doing... that link is 10 pin, but with only 6 wires connected. The colours are, purple/lt grn, black, Dk green/yellow, white, purple, and lt blue.

 

[brewmoody]

OK, its an inboard
There is a 4 pin harness and nothing is connected to either transmission?

Correct re the four pin harness. The trans temp and neutral safety switch are connected, buy not through the four pin harness.

 

[alldodge]

OK, then it does have a neutral safety switch on the trans, which could be the issue. The 4 pin is probably used when used on a stern drive

 

[brewmoody]

Yes, there is a neutral safety switch on the transmission.

 

[alldodge]

Yes, there is a neutral safety switch on the transmission.

OK, then the same thing could be happening as previously mentioned, and both are being effected because as Chris mentioned, the cable is connected between them. If you disconnect the cable then only one motor would slow down when it happened so this would tell you which one is the problem