swapping powerheads 74 to an 85 140 hp

[warrior1]

since i am here i have another question about swapping powerheads.

i have a 74 115 with no tilt or trim. runs good
i have an 85 140 with tilt/trim. thrown rod through block.

to gain the benefit of tilt/trim, can i put the 1974 115 powerhead on the 1985 140?

the outside of the engines look identical, exhaust housing and mounting points. is there any difference in the splines for the drive shafts, or anything else that would stand in the way?

 

[throwback2332]

Re: swapping powerheads 74 to an 85 140 hp

Just swap the tilt/trim unit, you did the 140 throw a rod??????? More headache than you really want. Go to BRP Parts and compare diagrams.

 

[Chinewalker]

Re: swapping powerheads 74 to an 85 140 hp

The 1974 is a much different animal than the 1985 - different motor mounts, different clamp brackets, different trim system, different lower units, different shift patterns, etc... Bottom line - no way to make the swap...
- Scott

 

[Dhadley]

Re: swapping powerheads 74 to an 85 140 hp

If they look identical you've got the years wrong. Post the model numbers so we know exactly what you have. The 74 is (obviously) a crossflow and a 1985 140 is a looper. Totally different, don't look anything alike. Get the model numbers, that'll let us "see" what ya really have.

 

[warrior1]

Re: swapping powerheads 74 to an 85 140 hp

ok. model #'s

115593 E - this engine runs well. (1975)
140843 C - this engine runs, um, not so good. (1978)


well. it seems i was wrong about years. i dont know what kind of crack i was smoking when i proclaimed i had an 85 year model.

so, now with the corrected info, will these powerheads swap, good 75 to the good 78 model.

or is it easier to just remove the transom bracket and tilt unit from the 1978 and put it on the 1974?

thanks for your help and ... wisdom

the 78 had catastrophic piston failure. #1 hole. the piston took out a fist sized chunk of the block, right behind the carb. i bought it for $50 as a parts motor. so far, well worth the $50. have used coil pack, starter, and carbs.

 

[Chinewalker]

Re: swapping powerheads 74 to an 85 140 hp

They're still quite different motors. The 115 has the older style clamp brackets that would accept a power trim unit on the outside, while the 140 should have the later style with the trim unit within the clamps. I'm not sure if you can interchange the 1978 swivel bracket and clamps with the 1975 style. I know the motor mounts are completely different, as is the lower mounting bracket. If the swivel bracket and steering arm are close enough, it might work, though...
- Scott

 

[Dhadley]

Re: swapping powerheads 74 to an 85 140 hp

You can make the 78 powerhead fit on the 75 but not vise versa. The easiest way to get to the internal power trim is to find a 1978 or newer crossflow powerhead that's rebuildable. It'd be nice to find a dressed powerhead for the 78 (or newer) that's rebuildable.