Johnson 115 V4 Interchange

I was wondering if I could use a 83 V4 115 on a 95 v4 115 lower unit. I am very new to outboard engines and still looking around for interchange information. If they are interchangeable, do I need to install it with all the controls or do you think just power head will work.

Re: Johnson 115 V4 Interchange

I am assuming that the 95 115 you are referring to is a crossflow type-nearly identical to the 1983 engine...... (OMC also made a looper 115 in 1995 and it is not the same engine as the crossflow.) The powerheads are the same cubic inches and will bolt right on-same gasket and bolts. There are some differences you need to adjust for. The older unit is a flatback model, rated at 115 hp at the crank. The 95 model is a bubble back model and rated at 115 hp at the propshaft. The later engine has slightly more useable hp. The older unit does not have a VRO combination fuel/oil pump. It used the older, simpler pump designed to used premixed fuel in the tank. The shift linkages are different under the lower carb, and it may affect the shift rod going down to the lower unit. Both trim units use the two wire system with relays. That trim wiring box mounting location is probably different between the engines. The control boxes are interchangeable between both engines, as they both use the red plug connector harness. The 95 uses a combination voltage rectifier/regulator, on the older engine they are separate components. OMC changed the cold-starting fuel primer system midway thru the model year, so the carbs may or may not have the primer hose barbs. Hopefully, someone else can contribute some additional comments.

Re: Johnson 115 V4 Interchange

Also, the 1995 lower unit used a two part driveshaft that is of a different design. While the 1983 unit will work, it does not fit the same and is sealed differently, so that more frequent lubrication and service would be desirable.

Re: Johnson 115 V4 Interchange

I hope its a cross flow, I havent seen either one of the engines yet. I am planning of buying a boat with a bad 95 v4 on it and I already found a 83 v4 crossflow. If 95 is crossflow I can swap the carbs and linkages and all that to get it aligned worse case scenario 83 has a bad Tilt&trim I can just use the 83 as is with 95s tilt&trim. If its a looper then I will be spending some $$$ to rebuild it. The picture included is 95. Is there any way to tell if this is a flatback or bubble back? Are we talking about the intake manifold being bubbled or flat surface when we say bubble back or flat back?

Re: Johnson 115 V4 Interchange

that looks like a crossflow, the bubble back refers to the exhaust, that bubble between the cyl in that pic.

Re: Johnson 115 V4 Interchange

Your 95 picture is of a 115 crossflow with the bubble back exhaust. You may find the carbs on the 115 jave larger throats than the older 83 unit, but you should be ok to swap them onto the 83 block. The reference to flatback or bubble back refers to the exhaust covers between the heads. The flatback was a lower hp versions, the bubble back was typical on the higher hp engines only.