[hawilson2]

I am looking at buying a 2005 Yamaha 115 4 stroke. I already have (and love) a 1996 C115 2 stroke Yamaha installed. Can I use the old Yamaha binnacle mount control box and guages (2 - tach and speed) with the new engine? I believe I will need to buy a wiring harness adapter. Is that correct? Thanks in advance.

[Raven]

I did essentially the same thing.. replaced a 1996 200hp vmax with a 2005 F150 4-stroke. The dealer installed the motor using the same controls, instruments and wiring. The issues to date are:
a. trim indicator doesn't work. Dealer says motor/indictor are incompatable. Don't know if that is true or not.
b. Oil sensor: I don't know whether the oil indicator on the old gauges are doing anything or not. If they are to indicate oil pressure then they don't appear to be working since there is no indication zero oil pressure when the engine is off.
c. Overheat indicator and buzzer. I can't tell if these are functional or not. I do not know a way to test it.

This setup had been working for a year but now I am having problems with zero fuel pressure (see earlier post) and do not know whether the problem is in the old controls or not.

[rodbolt]

trim indicate wont work, tach will but nio visuals.
buy the later tach
the trim harness is the same.
in 95 they changed from round to square connectors, in 99 they changed to a 2 wire trim sender.
the later tach is selectable for 4 or 2 stroke,2 or 3 wire trim sender and 6 or 12 pole altenator.
to test the overheat on some of the F motors requires a resistor jumped acrossed the temp sensor and shorting the temp switch.
its all in the Marine Technical Guide.