Looking for a solution for Carburetor problem

[Intoodeeep]

I currently am working on a Johnson 1979 235 block that I have just rebuilt (no serial #’s but matching case halves). I am currently using the intake manifold, carburetors (1-3/8) and electronics from a Johnson 1988 175. The engine originally came to me without VRO. It’s a long story and it’s not worth getting into how it all came to be this way. So please bear with me. I have done enough research and spoken with enough people to know this combination will work, but may have to tweak some high speed jetting. I am using low compression heads 323872, 323873, with new standard pistons 3.5”

The problem is, besides having to chart the high speed jetting and purchasing another set of jets, the carburetor float bowls are the plastic ones and they are badly warped. They didn’t leak last used but they did seep badly. Regardless, new float bowls are about $130 each plus all the four jets have to be purchased for each bowl for a total cost of $522 to fix all three carbs. Its flat out cheaper to buy a used set of carbs, but I can’t find the ones in the 1987-1991 175hp year range with aluminum bowls to fix the problem. So I am looking at other carbs.

The 1984-1985 235 carb float bowls look the same. Can I use these or even those carbs and just change the jetting around a little?
The 1986 175 uses the same intake manifold as mine and the 1987-1991 175hp, but has a different part number for the float bowl. Everything else seems to be the same. Is this float bowl the same or not?

Alternatively, the 1980 and 1981 200HP use 1-3/8 carbs too as well as the same low compression heads and pistons. Can I use these carbs and leave the jetting as is? I know the timer base is the same but the rest of the electronics/ignition system are different from the 1988 175hp 35amp system I have and the 1980-1981’s 200hp ignition/electronics 10 amp system. Ideally not having to fool with re-jetting would be ideal. I’m not sure how the check valves and primer setup gets routed in this case because there doesn’t seem to be a place to run it to the top of the carbs.

I am just trying to make this work and come up with the most ideal and cost effective solution. Thanks in advance. Josh

 

[gonefishin485]

im not an expert on this but ill give you my observations, you could most likely use what ever bowls you like, but as far as the carb body goes, the throat size between a 175 and a 235 could be different, ill give you an example, on the v4 motors, three different carbs were used, a 1 inch, a 1 5/16, and a 1 3/8. the bowls were the same but the throat sizes are different. id look and see what size the 235 block uses and go from there. here again, not an expert but a lot of horsepower differences were in the portings and carbs, so the electronics should work as long as their both for a v6. if your not building a high performance application, i would pull your jets out of your carbs, and see if you can find a cheap used set, reguardless of horsepower as long as the throat size is the same.

my best suggestion would be to ask this at screamandfly.com, the people over there are big into building motors and high performance applications. hopefully they can help you out better.

 

[Bluefish]

~~I have carbs and the intake manifold off a 1990 Evinrude 150hp if they will help you PM me
Bob

 

[emdsapmgr]

Those plastic bowls are a real problem. You need to replace them. Not whether they will fail, but a matter of when... I'd be very leery of using the 79 bowls on the later 175 carbs. They are different. The 79 bowls have the idles and high speed jets on the side of the bowl. No mid jets but does have pullover jets between the main throats. Your 175 carbs have the idles in the upper carb body, and also have (added) mid-jets which are inside the bowls. Different from your 79. This may add up to different internal passages that won't match up correctly. Think I'd be looking for a set of bowls from an earlier 87 or 86 that are the same configuration but aluminum. Be sure they physically match exactly with your plastic bowls.

 

[Intoodeeep]

Emdsapmgr, The carbs I am using are from a 1988 175. They are 1-3/8. The 1984-1985 235 carb float bowls look the same. Can I use these or even those carbs and just change the jetting around a little?

The 1986 175 uses the same intake manifold as mine and so does the 1987-1991 175hp motors, but has a different part number for the float bowl. Everything else seems to be the same. Is this float bowl the same or not?

Alternatively, the 1980 and 1981 200HP use 1-3/8 carbs too as well as the same low compression heads and pistons. Can I use these carbs and leave the jetting as is? I know the timer base is the same but the rest of the electronics/ignition system are different from the 1988 175hp 35amp system I have and the 1980-1981’s 200hp ignition/electronics 10 amp system. Ideally not having to fool with re-jetting would be ideal. I’m not sure how the check valves and primer setup gets routed in this case because there doesn’t seem to be a place to run it to the top of the carbs.

Just looking for options as the carb years for the aluminum bowls are impossible to find on a used set of carbs. The 200hp I was speaking about above seems like a good option but wanted your opinion. Again, lo0king for options

 

[Faztbullet]

Take a piece of glass and 600 grit paper and sand em flat, have done many with no problems......

 

[Intoodeeep]

They are really warped. I think the plastic would end up being too thin after I was done. The guy I purchased this block from suggested the same thing originally, but after looking at them with a straight edge its bad.