850 wont crank over, no power to gauges...

[centerline]

after pulling the 1975 85hp motor and wiring out of a donor boat, I placed the motor on a motor stand and had the engine tuned, new impeller, lower unit oil changed and running great and dependable....
now, after installing it all in a newly reconditioned glasspar hull, and connecting the wires, cables, steering and trim system, the engine wont crank over with the key switch.....
the red wire on the start solenoid is hot and the ground is good, but what I cannot determine is what wire gives voltage to the ignition switch so that it can power the start relay and supply power to the volt gauge....
I would have thought there would have been an ignition supply wire stacked on the start solenoid lug with the batt hot wire, but there isnt.....
.........is there a fuse somewhere that may have blown?
.........what color wire is the hot feed into the ignition switch?
.........where else should I look for the problem?

 

[merc850]

Follow this diagram

 

[centerline]

Follow this diagram

I have the diagrams in my seloc manual,and have studied them, but for some reason i cant determine which is the hot wire going TO the key swich, or where it originates from.

 

[Chris1956]

There is no fuse in the circuit, or at least Merc never installed one. Power goes from the red wire on the rectifier into the motor wiring harness, thru the quick disconnect pin and up to the keyswitch, on the red wire. When the ign switch is in the start position, power from the red wire is connected to the white wire and yellow wires. The yellow wire runs thru the neutral interlock (in the MerControl) to the starter solenoid..

 

[centerline]

There is no fuse in the circuit, or at least Merc never installed one. Power goes from the red wire on the rectifier into the motor wiring harness, thru the quick disconnect pin and up to the keyswitch, on the red wire. When the ign switch is in the start position, power from the red wire is connected to the white wire and yellow wires. The yellow wire runs thru the neutral interlock (in the MerControl) to the starter solenoid..

thank you... im trying to nunderstand the path from the battery to the engine, and the large red wire coming in thru the harness connection goes directly to the post on the starter solenoid, which is hot, but as there in no other wire sharing that terminal, how does the power get to the rectifier, or out to any other circuit?.... it would appear from the diagram that the small red wire junctions into or splits from the large red wire as it comes in thru the large pin connector. which seems silly since there is a post readily availabe for it to be connected to.
i am not at the motor now, but when i get back i will trace all the red wires and see where they go, but i know there is no power on the red wire at the switch box assembly or the rectifier....

 

[Chris1956]

Those Quick Disconnect plugs can develop breaks in the wiring inside of them. Do yourself a favor and Get some ring terminals and make a power wire from the red battery cable on the starter solenoid to the rectifier. If still no power to the red wire on the switchbox, make a wire for that as well.

 

[centerline]

Do yourself a favor and Get some ring terminals and make a power wire from the red battery cable on the starter solenoid to the rectifier. If still no power to the red wire on the switchbox, make a wire for that as well.

Consider it done..... now that I know the routing of the wires and after I inspect them, Installing a permanent jumper was my plan as it would be more depenable and easier to troubleshoot any future problems. Thanks for the help

 

[centerline]

problem resolved.... found a bad connection (intermittent) where the small red wire splits from the large red wire.... installed a jumper from the large red wire at the start solenoid to the red wire on the switch box assembly. BUT that wasnt all of the problem... somehow between the time that I last ran the motor on the stand, and got it and the harness installed and connected in the boat (about a week) the key switch failed and would not throw power to the white wire when turned on..... so I replaced the key switch with the newer push-to-choke style. thanks for all the help