swap a 70 HP 'Rude for a 90, what fits?

[joetheis]

Never really happy with what I have, always looking to screw with it.....
I have a 19' Grumman SF 184 boat with a '91 70 VRO 'Rude.
Runs good, swapped out to a 4 blade prop and hydro foil to get it up out of the water fast.
Motor has good compression, starts pretty easy, but........
I'd like to put a fresh 90 HP on it.
I see a company in Fla rebuilds 70 and 90s, and for $1000 more I can get a 90 with a 2 year warranty.
IF, IF, I do the swap this off season, will the control wiring be the same?
What WILL I have to change other than motor?
Both have power trim and tilt, these reman ones have the VRO un hook (mine is still operational).
Just trying to get an idea of the $$ here.
Thanks!
Joe

 

[1983 ercoa 21']

Depending on vro the controls should work !
evinrude and Johnson used the big red plug under the hood for several years. If the 90 don't have vro you simple don't hook yours up and pre mix your fuel.

 

[1983 ercoa 21']

If I remember right the 90 will have different gearing in the lower unit and you might be able to start with the same prop also. You might be right on or you may have to change pitch but the prop you have now should fit the v4 lower unit.

 

[1983 ercoa 21']

Tilt and trim could be different plug ins if its a older 90 think they change in the early 80s to the relay system. If it's different you you may have to track down the solenoid type control that will plug into your wires from your switch at the transom area of the boat the best thing to do would be remove your relay setup off your motor to the point where the wires plug in that go to the pump.

 

[joetheis]

Rodger!
I've been looking at controls on line seeing the part # for a 70 then for a 90, but so far all it is, is just 'Rude controls, pre and post 1997.
IF I pull the trigger, it won't be until the end of the season, when I drag the boat home from N.Y. and get ready for the "Big Sleep".
I think best bet is when I call to order the new motor, ask them to hold my hand through what I need, get what I need for the swap.
IF the props fit, cool!
At least I have a starting point, or ask @ on here for what everyone else is running.
Thanks!
Joe