Johnson 120 plastic carb AND float bowls warped

[Skyla316]

Re: Johnson 120 plastic carb AND float bowls warped

I installed the carbs on my throttle bodies, an took to the dock an when you wot if bogs for first 10 seconds then clears out but either is a restriction or something but its not turning rpms at first take off, almost made me feel like one plug wire was off at first but then as I said it got full power so I'm lost an yes the new carbs are freshly rebuilt but the parts store didn't have the float valves in stock so I used the ones from my original carbs as they were just rebuilt.
Problem I see now is when I compare my motor 1985 120 to the donor motor 1992 120, the float valve assembly part numbers are not the same. Is it possible that even tho they look the same that are actually not in size?

 

[Faztbullet]

Re: Johnson 120 plastic carb AND float bowls warped

Part # has superseded on floats...Your 120 is a small bore 2.7 and the 92 is a big bore. You will need to use your high speed jets and intermediate jet for it to run right and the idle jet should be ok .

 

[Skyla316]

Re: Johnson 120 plastic carb AND float bowls warped

Are u referring to the brass offices on the left side of the carbs as the high an intermediate jets or? an is my float valve OK to use from my 85 120?

 

[Skyla316]

Re: Johnson 120 plastic carb AND float bowls warped

Just went on ********** to compare part no an jet #s an all 3 are different between my 2 120 motors, so tomorrow I'm going to change all 3 over cause my engine is running like crap an barely gets on plane an while trying to do so an after it does it cuts in an out almost making me think I had an electrical problem but I spark tested all coils an they are strong but in my factory manual it does tell me how to adjust the spark advancement (cause my brother started messing with it in this process an now I believe its out of time) the manual doesn't say "the factory setting is x turned from all the way in or out" so I'm lost as where to start from or does that adjust of sound an feel under load in the water??

Again everyone thank you for your help its very much appreciated, I love this website.

 

[Faztbullet]

Re: Johnson 120 plastic carb AND float bowls warped

Take the high speed jets from old carb ( their behind bowl drain screws) and install in the 92 carbs, the idle jets are are the ones on carb at 9 oclock....

 

[Skyla316]

Re: Johnson 120 plastic carb AND float bowls warped

I did an it started easier but need to get the timing straight I believe.

I did notice that looking at the throttle bodies from the 2 engines that they had internal grooves that were shaped slightly different.
Reason why I mention this is because I used the 92 120 carbs with my 85 throttle body so with the groove shape being slight different is this going to cause a fuel flow problem?

 

[LeeRoss]

Re: Johnson 120 plastic carb AND float bowls warped

Chances are even if you get new plastic it will happen again. I replaced mine with plastic the first time and they didn't even make it 2 years before starting again. Luckily I was able to find a salvaged older motor that had aluminum blows replaced the jets to match my OEM setup and never worried about it again. But if you cannot find or get bowls for yours (a friend of mine bad the same problem) we went and purchased a 12"x12" piece of gas resistant rubber they sell it for cutting and making your own gaskets and just made out own. I believe he used 1/8" material. We also took a piece of flat stainless and a heavy weight heated it to about 130 degrees for a few mins and let the heat and weight kinda flatten it out that seems to still e working to this day. He's also going on about 2years.

I have a 130 hp 1995 Evinrude looper, same idiotic plastic carbs, and I think it might be suffering from the same issues. Windsor: This sounds good, but I'm not getting a mental picture of what you did. Where does the stainless go?