OMC V4 xflow adapter question

[zookimota]

This may be a really dumb question, but in the process of looking for a gear set for our '76 Evenrude 115, I came up with a couple of other xflow motors.
What I found is a '76 135 xflow that is blown with a good lower, and a good '77 140 xflow powerhead.

Here's the question. The adapter for the 135 had a slightly different bolt pattern than the 140 powerhead. Can the 2 center holes on each side of the adapter be enlarged enough to allow mounting the 140 powerhead to the 135 adapter and mid? All the other bolts line up. Those 2 are off by about 1/2 a hole. I have both powerhead gaskets and it appears that is the only difference.

If it can't be done, at least we now have a good lower for the 115, which by the way is a little weak. Thought stepping up to the 140 might be a good move.

[hsbob]

be sure to get the filler blocks for converting the 115 to 135/140. along with the tuner housings and carbs. that way you can make almost a 140 from your 115

[zookimota]

Both these motors, the 135 and 140 have the whole works. Our 115 is weak and has lower unit problems also. Needed the front gear or a whole lower. In the process of looking for lowers, we came across these 2 engines. The 135 is complete with lower, but blown power head. The 140 is only the powerhead, but has good compression on all, but it needed electronics.
We moved the 135 electonics to the 140 and planned to mount it on the 135 mid but the adapter bolt pattern is slightly different. That was the reason for my question about redrilling the adapter to fit the 140 powerhead.

If worse comes to worse, we can rebuild either the 115 or the 135 and we'll have all the stuff, but sure would like to use the good 140 if possible.

[Paul Vaillancourt]

I looked long and hard at the very same thing last year, and came to the conclusion that I could not do it there is too much that is different, water passages and exhaust. Also you have to look at the way the lower is shifted, it will probably also be different. What I found is that you need to use the old style adapter with the older power head. The lower unit could be used but you would have to use the intake manifold that goes with the lower if the shifters are different. The lower units also have a slightly different gear ratio.
good luck,
Paul

[zookimota]

The shifter linkages are the same! Both use the screw on thing at the top of the shift rod and have the split arms that pivot on a bolt in the front of the block to work the shifter...identical.
The 135 is a 1976 and the 140 is a 1977.
The water passages look identical on the bottom of the blocks, the only difference in these two is the bolt pattern on the second and third bolts from the back on each side, that I can see. Looking at the book, both used the 2 water feed lines from the pump, at least they do use the same water pump housing.
There are apparently only 2 V4 powerhead to adapter gaskets that fit all the xflow V4's and this is apparently the year of the change. Both gaskets come in most V4 powerhead gasket sets.

Went back to see if the guy we got these from still had the 140 adapter and mid, and he said he sold it to someone else that wanted the tilt and trim. He said the powerhead had low hours, the lower had a broken case, and he also sold the electronic parts(box and coils) to someone that needed them. All he had left of the 140 was this powerhead minus box and coils.

[Paul Vaillancourt]

The stuff I was using was 1979, and it had only one water passage going up to the adapter from the water pump. My 1973 had 2, and the exhaust bolted on differently. The reason i changed mine was so i could use the tilt and trim unit from my 1979 stuff. I used the 1973 powerhead, adapter, mid and lower. I removed the Steering stem from the 1973 and used it in the 1979 trim unit with some custom bushings.

I'd have to say that if everything else lines up there should be no problem with drilling 2 new holes.

Maybe Laker Can help you with some more info.
Paul

[hsbob]

get the power head for the filler block. at one time you could buy the rest of the parts, but they would not sell the filler blocks. the full tuned unit on a 1978 115 was good for 5+ mph on my 16' boat. at that time the dealer said early 135 model had a balancing problem with the crank ??????

[squarles]

I asked the opposite question a couple of years ago, older block going on later mid, and was told it could be made to work.

The shift linkage changed when the lowers changed from the electric shift model that you have which was 78 or 79. That is the difference Paul is talking about and the intake is different. The 77 140 had the electric shift lower. I think 77 was the first year for the trim to be mounted inside the bracket also.

Stephen

[Paul Vaillancourt]

there was also a hydro-mechanical lower unit that had a mechanical shifter that bolted on the intake differently than the 1979 style. The older lower units had a different shape than the newer.

[Paul Vaillancourt]

1973 every thing except the 1979 trim unit.

[zookimota]

This is hydro/mechanical shift on both motors, not electric.
We actually had the powerhead set into position and all bolts worked except the ones mentioned on each side. Everything will hook up OK as far as the shift and lower unit, water hoses, linkages, etc. Minor differences in the adapter gasket where the mating surfaces meet in front of the exhaust opening have been addressed by cutting a new base gasket with that portion in front of the exhaust opening extended wider to get between the mating surfaces better. All the other water passages, exhaust, etc all line up perfectly.
Don't know what the effect will be using the 135 tuner vs 140 tuner. The most radical difference I can see is the way the timing is stated on the sticker on the intake cover. The 135 says 20 degrees max timing, the 140 says 28 degrees. When we moved the electronics, we compared the timer base and stator and they mount and look the same. We did use all the electronic stuff from the 135. We did not mix or match.

[squarles]

I'd be careful with the timing, run it around 24 or so, you could still get leaded gas in '77. All of the electrics are the same, they changed in '78 to the power pack on either side instead of the one in the back like you have. Don't worry about the tuner, I think they're the same on all the V4 crossflow, except maybe the 85 HP.

[Laker]

It can work.
I had one adapter welded up and then I redrilled it.
alittle history. 1972 was the last of the electric shift. 1973 is a hydromech shifting lower unit until 1976. In 1977 the 140 was still hydromech but changed its shape to a more modern design with a swept back skeg and 2:1 grears. 1978 is the first Mechanical shifting gearcase, mostly the same until the end of production.
Watch your jetting but 28 degrees makes the most power on all the performance production V4s

[zookimota]

Only slight modification to the bolt holes in the adapter and mid, and the powerhead went on and bolted up good. Shifter hooked right up with no problem, even got the wiring harness and cables put on. Next project....getting it started and see what happens. Everything is a go at this point.