Swapping motors, Wire harness question for power trim

[chrisg]

Looking to change my broken '87, 115 with a '99, 60 bigfoot.

Mercury marine said the harnesses are the same, so they will plug in. When I looked at this ?99 60 HP Bigfoot, I saw two wires (with connectors) on what appeared to be coming from the power trim unit. When I looked at my motor (?87 115), there are no wires with connectors coming from the power trim, only a harness going into the engine. The main harness has a 8-pin round connector- which I verified is on my 115). Does the power trim, tach and starter all go through that connector. ( there must be a separate cable for the battery/ starter cable that I did not see- I can?t see having the heavy gauge wire on the battery terminals, only to go through a small pin on a 8?pin connector.) I wonder if the owners manual would have the harness hook-up diagrams.

Also, I noticed from other postings, I may have to change the tachometer, Going from a 6 banger to a 3 banger?

Thanks

 

[Chris1956]

Re: Swapping motors, Wire harness question for power trim

Chris, For some reason the PTT connectors on the newer merc are external bullet types. You should be able to adapt your older PTT control to work with them. You will end up pulling the PTT control wires to the motor, connecting them with bullet connectors and taping them to the main harness. The battery cables run directly from the battery to the starter solenoid secondary for the plus side, and directly from the battery to ground for the negative side.

 

[chrisg]

Re: Swapping motors, Wire harness question for power trim

Thanks, sound like there will be some minor wiring to do. Now to find someone who wants to come to Iowa and get my 115.