1973 cross tuned Johnson 85 to 135 info

[NoHeadNed]

Hey guys, new here. I've been searching and reading for days now. I have just purchased a 73 t17 Thunderbird tri hull with original v4 85. I've read a few things about upgrading. What all do I need to give this thing more hp? I just ordered 135 carbs and all new ignition electric parts. I plan on adding the carbs and replacing the coils etc next week. I'd love to know if this is all I need, or if I'm needing reeds and machining to make this go the way I want it to.

 

[racerone]

No need to search any further !-------The 85 HP has a smaller diameter bore and less displacement .-----It is a smaller engine !

 

[NoHeadNed]

Well dang. What can I do now? What can I expect with he carb upgrade?

 

[NoHeadNed]

Scratch the 135 idea and let's switch to making this a badass 85...

 

[NoHeadNed]

No need to search any further !-------The 85 HP has a smaller diameter bore and less displacement .-----It is a smaller engine !

are you saying I need a 115 or 135 powerhead? What are the best parts engines to buy to make this work?. Or to make it the strongest period...

 

[racerone]

Yes the 115 and 135 are both the bigger displacement.-----The 135 has the tuned " bubble exhaust " to make it breathe better.----And the 1973 V-4 powerheads are unique in that very little in the way of 1972 parts will fit.-----And few of the 1974 model internal engine parts will fit.-------A lot depends on your local area as to what motors you can find.----I know where there are 135 HP models available.-------Your location ?

 

[NoHeadNed]

Wilson NC. I just got 2 free 80s models 70hp v4s. One is supposed to need a harness and prop. Also supposedly a race engine made into a 115? What have I got here? How to tell part numbers?

 

[racerone]

??------I can not recall a 1980's V-4 rated at 70 HP.-----I can not speculate on what you have here.------Post pictures and more pictures.-----I would like to see a 70 HP made into a 115 HP racing engine.-----Unless you stumbled on a 1968 model GT 115 which is a rare motor.

 

[NoHeadNed]

I commented under each picture. It definitely has a different shift linkage. And I don't see a tag anywhere...I'll take more pictures and look for casting numbers or parts differences Friday. I hope to be more prepared by then.

 

[GA_Boater]

How long was that motor laying in a ditch before you picked it up.

Is it locked up?

 

[Faztbullet]

Take power trim off and send rest of it to recycle yard....

 

[NoHeadNed]

It was free . I figured it was worth it for the tilt lol.

 

[NoHeadNed]

So what is the most I can get out of my original 85? Will the 135 carbs give it any more hp? or not work?

 

[racerone]

I appreciate accurate postings.----Those are not a 3 cylinder 70 HP.------I can see why they were free.

 

[jimmbo]

So what is the most I can get out of my original 85? Will the 135 carbs give it any more hp? or not work?

The 135 carbs will probably cause a stumble/bog on Acceleration, and some erratic running at midrange rpms.I doubt there will be any power gain.

In 1971 - 72 there was a 100 HP that had the same Displacement as the 85 hp, What the differences are, I don't know. Could be different Porting, Exhaust Tuning, Carbs. A thorough comparison of the Parts Lists for both engines would show the differences

The difference between an 85 and 100 is about 3 mph, between an 85 and 135, about 8 - 9

 

[racerone]

Intake ports on a 135 HP are bigger than those on 90 HP blocks.

 

[Texasmark]

??------I can not recall a 1980's V-4 rated at 70 HP.-----I can not speculate on what you have here.------Post pictures and more pictures.-----I would like to see a 70 HP made into a 115 HP racing engine.-----Unless you stumbled on a 1968 model GT 115 which is a rare motor.

Nope on 70 hp V4. Back when the New, totally redesigned OMCs came out in '71 Seafoam White cowl and dark green everything else, as I recall that year's 60 to later become the 70 and hot dog 75 were loop charged triples spun off the first looper, the Rude Triump 55 back in '68. I bought a new '72 125 V4 cross flow. When the 135 came out in '73, lots more engine and one thing it had that I couldn't get for my 125 was PTT. I was able to get a SST prop that would backfit my engine.

And yes the 85 was lower displacement than it's big brothers. You can diddle around the www and find viewable sales brochures, free of charge, for popular engines way back into the '50's. Let's see if I can find one in my bookmarks........Yes I found one for 1975 Johnsons: https://issuu.com/liquidnirvana/docs/1975---johnson-outboards--x---wm-

Give it time to load then flip through the pages.....there is a + sign for enlargement. There are others on this site...makes for neat browsing.

 

[NoHeadNed]

[No message]

 

[NoHeadNed]

It's a 84 115 loop but will that tilt work on my 73? Thank you guys for all the input so far. After digging in parts diagrams I've figured out a few things. The carbs I ordered and all the electronics are only going to work on my 73. The 84 115 looper will be gone thru and perfected thx to y'all's future input. But for now I think I'll port match the 85 and tune it with jets if it needs any major adjustment.

 

[racerone]

I like accurate postings !!-----Where did you get the idea that this 115 HP is a looper ???----And I do believe it will take major effort to fit the trim / tilt on your 73 motor.