bubble exhaust pee tube 85 hp to 135 hp

[toplesshorse]

I have a 1976 85 hp Johnson. I just installed a 135 hp bubble back exhaust plate. There is a fitting in the bottom of the new plate that was not on the old one. I plugged it. Is this going to be a problem? Doesn't the water exit the same way it did on the old one out the ports below the power head? Do I need to put in the fitting and drill a hole for a tube in the bottom of the engine housing plate? I plan on running it in the drive way with the water hook up to test. Make sure no leaks.

By the way if anyone wants to try this you will need monkey hand like my son and a short 1/4" drive extention in order to reach the lower three bolts. Be patient and have a magnet on a stick ready. You will drop the center bolt a few dozen times. Also, go with 1/4-20 x 1 1/2" bolts grade 5.

 

[1730V]

Re: bubble exhaust pee tube 85 hp to 135 hp

I'm not sure what that bubble plate is going to do for you on an 85. There was more to the 115 and 135 than that plate.

What size is the fitting?

Those bolts aren't too bad if you loosen the lower cowl bolts and drop it down about 2 ". Been there.

 

[toplesshorse]

Re: bubble exhaust pee tube 85 hp to 135 hp

Thanks, it was a black plastic elbow with about a 3/16 " barb for tubing.

I know the bubble is not all, just first thing I could get the parts and get done before the season is finished. We are about out of water in north Georgia.

I plan on adding carbs with boydsen reeds also. I was thinking about 115 hp carbs instead of 135s. I don't know if the 135s will be too much and load up. What do you think. Should I go to 135 then jet em down.

The motor is on a 15.5' glasstream fast hull bass boat.

 

[R.Johnson]

Re: bubble exhaust pee tube 85 hp to 135 hp

Did you install the inner exhaust plates, or just the bubble back?

 

[iwombat]

Re: bubble exhaust pee tube 85 hp to 135 hp

That's the fitting for a tell-tale. The 115 & 135 was a whole different beast than the '85. I think you're going to need more intrusive machining to get the boost you want. Bolt-ons alone aren't going to cut it.

 

[1730V]

Re: bubble exhaust pee tube 85 hp to 135 hp

That is the telltale tube as iwombat stated.

The 85 is a different animal. I think it is even less cubes, at least they were in '73': 96 cubes as opposed to 99. I think.

 

[toplesshorse]

Re: bubble exhaust pee tube 85 hp to 135 hp

So plugging it should be no issue. Yes I put the inner baffel in, and trimmed the gasket to match the port detail. I believe the 85 and 115 are the same bore and stroke in '76. The 135 may be more stroke. If I remember some research from a few months ago. Anyway I am not looking for a lot. Boat runs well just want a little bit to get some more prop as I fish and pull my kids on wakeboard. I have a swivel eze tow bar in the back fishing seat hole. Works pretty well and comes off easy for fishing trips.

 

[1730V]

Re: bubble exhaust pee tube 85 hp to 135 hp

Won't hurt to plug it but having the telltale is nice.

 

[emdsapmgr]

Re: bubble exhaust pee tube 85 hp to 135 hp

Likely the bubble back exhaust is from a newer unit. The telltale fittings were never on the 135's-they came out with the 140 engines in 1978. Your 85 hp is the smaller cubic inch engine-92 cubic inches. Same stroke, smaller diam piston. I put a set of large throat (1 5/16") carbs on a small bore 85. After lots of fiddling with the high speed jets, (it was overfueling) they worked out great. Worth the effort. I would add the composite reeds. While you have the intake off, consider adding a set of 4 intake filler blocks from the 140. 322684. While they are NLA, they are worth adding.

 

[toplesshorse]

Re: bubble exhaust pee tube 85 hp to 135 hp

What are the 1 5/16 cabs off of a 135? Do you remember what size jet you put in.

I have a pretty good back ground in bikes so jetting is a necessary evil.

 

[toplesshorse]

Re: bubble exhaust pee tube 85 hp to 135 hp

What are the 1 5/16 cabs off of a 135? Do you remember what size jet you put in.

I have a pretty good back ground in bikes so jetting is a necessary evil.

 

[emdsapmgr]

Re: bubble exhaust pee tube 85 hp to 135 hp

I put a set of old large carb 125's on a 72 85 hp, with the intake stuffers. Did not change the heads. The idle jets were of no concern, since those carbs had the adjustable idle screws. (they worked out well.) The mains were another problem. Spent hours jetting it to run on those carbs. My memory is not the best, but the original 85 mains were 57's and I think I settled on 62's. (The 125 carb mains were 72's and it would not run right.) Final result: really mad a big difference. Worth the effort. If you change to the 140 (higher compression) heads, you will have another scenario. The engine will need more fuel. You may find it will run on 66's or 68's. Carb designs changed over the years, so you'll have to play with the carbs you get. Learn to read the plugs. Any set of large carbs from a 135 or 140 will work well. A set of large carbs from an early 90's 115 bubble back will also work, you just need to change to the primer choke system.