140hp crossflow

[Jmr1974]

So the 135hp I have a pic of above is a1976. How many parts are interchangeable with my 1980 140hp? Are the heads higher compression heads than my 140? Carbs? Lower unit? Bubble back? I think the block would be the same 99ci. I think I can get it cheep, just wondering if it’s worth it for the parts since I just picked up the 115hp for odds and ends parts…

[LakeFever]

Iirc the 76 135 had the highest cr heads but they dont have the brackets for coil mounting. The numbers you posted are the good low comp ones. The later versions on the 110’s were really low comp. iirc the 79 140 was the last year with the high comp heads. I was building a 140 a couple years back and there was some great threads going with good info. Theres also the unicorn tuner for these a one year only deal.

[powerabout]

135 had 2 versions of heads, pretty sure both tighter than a 140.
They ran fine in OZ as we still had leaded 98 when they came out and for the next 10 years

[Jmr1974]

Iirc the 76 135 had the highest cr heads but they dont have the brackets for coil mounting. The numbers you posted are the good low comp ones. The later versions on the 110’s were really low comp. iirc the 79 140 was the last year with the high comp heads. I was building a 140 a couple years back and there was some great threads going with good info. Theres also the unicorn tuner for these a one year only deal.

the compression #’s I posted were for the 115hp I picked up last Saturday, this 135 I haven’t bought yet just curious if it would make another good parts motor for my 140?

[LakeFever]

I dont know a ton about the 135’s but aside from the 90 the blocks and porting are the same
from what i can recall. The bubble back and stuffers are what set the 135 and 140 apart from the 115. Some had the big carbs some didnt but from what i read there isnt really a lot of gains with the bug carbs but just what i read keep in mind. I ended up buying three of these motors myself; a 79 140 and a pair of late model 90’s. Never got around to hanging one on my vandal i got the 75 on there working pretty good so i left it and ran it.

[Jmr1974]

I dont know a ton about the 135’s but aside from the 90 the blocks and porting are the same
from what i can recall. The bubble back and stuffers are what set the 135 and 140 apart from the 115. Some had the big carbs some didnt but from what i read there isnt really a lot of gains with the bug carbs but just what i read keep in mind. I ended up buying three of these motors myself; a 79 140 and a pair of late model 90’s. Never got around to hanging one on my vandal i got the 75 on there working pretty good so i left it and ran it.

ill probably go take a look at it this weekend, it’s not a far drive from my house. Can never have enough parts for cheap.

[LakeFever]

Thats exactly how i see it. Better to be lookin at it then lookin for it lol. I have a four v6 mercs now too for the same reason

[MrG]

That’s a good block esp if it’s a freshwater engine little mods like cleaning up the casting inside intakes
Radius all of its corners and in the exhaust matchup inserts and fix the plunge cut for the bulb dump back to block .if you can find some reeds from a junked 175 60deg Etec there big on flow will fit right in and make big power

[Jmr1974]

Sounds good. Thanks.

[MrG]

I have a 15 inch mid and lower with bobs cone and a cut trim for that engine

[Jmr1974]

I have a 15 inch mid and lower with bobs cone and a cut trim for that engine

Oh boy, now my wheels are turning. This would work for the 1980 140 correct with a jackplate? I did a splashwell delete? Don’t know why it wouldn’t just asking.

[MrG]

Yes it would it’s a land & sea kit or you can make a tiller motor out of it 14 ft skiff

[Jmr1974]

Yes it would it’s a land & sea kit or you can make a tiller motor out of it 14 ft skiff

What would be the benefit with the 15” for me on my Ventura? Just curious, kind of a greenhorn about this stuff. I have a brand new bobs cone kit in my garage I was going to put on the 140 but after I see how it runs with the standard case.

[MrG]

What was a problem was they had a top L ring and hi rpm caused ring failure I think it’s was in 76-77 models just check when the heads are off those pistons should be swapped ore you could look thrue the transfer windo plate

[James45157]

the pistons were lighter bad gas was the problem i rebuilt a lot of them back then use good gas drop timing back 2 degs use 93 pump gas should be ok