1994 115 Evinrude Carburetor problems

[1bigchevy]

I have a 94 115 Evinrude I recently change carburetors due to wear in the butterfly linkage. when I installed newer Carbs. I had to adjust the idle up for them to even run. Ever since then I have had problems setting the idling high enough,to run in the water. seems not to be responsive through the adjustments which is about to the max.. (Meaning I can get it to idle around 1400 on a hose then all of a sudden it idles around 1900 on a hose then the next time I crank it up back down to 1400. I took them back off and went through them again and I notice the butterflies has day light through one side of the butterflies and the carb throat . will this make it idle low and if yes is there adjustments on them ? I have checked compression between 120 and 115 on all cylinders. I adjusted the carb. floats level using the line on the floats. any help would be appreciated thanks

 

[jakedaawg]

Do you have a manual? Try the Sychronization process. You need all four butterflies to open and close at the same time

 

[1bigchevy]

yes, I have done the sycronization both are openin gup at the same time. but with the butterflies closed there is daylight on one of the sides not the bottom. I dont know if this is a common problem ? . I do know my other carbs. are sealed all the way around.

 

[emdsapmgr]

At idle, both butterflys need to be closed. There should be an adjustment on the carb arm of one of the carbs, in order to have both carbs completely closed at idle. If one carb has any extra air coming into the carb, it will draw fuel from mid jets and that can cause a high idle or an uneven idle. A factory service manual is what is best to follow when doing this procedure.

 

[1bigchevy]

Thanks for all the help on trying to fix this. Back in the early summer I realized I had some play in my throttle shafts but they ran great. A mechanic told me that could cause a lean condition. So I bought some used carbs. And switched out the jets both carbs. Were 1 5/16. But the new carb idles really low and I can't get the idle up on them and they almost cut off when I trim the motor all the way down. I fought this for a month or so. Tonight I installed my old carbs. Back on and my motor idles perfect. What could be wrong with the other carbs. Any suggestions ?

 

[emdsapmgr]

Sorry, this was a dual post, see response #7, below.

 

[emdsapmgr]

Was there some reason you swapped out the jets in the new carbs? Not all carbs are created equal, even though they may be 1 5/16" throat carbs. Internals and carb bowls are different. Some carbs have only 2 jets for each throat, others have three. So they may flow differently. They are jetted from the factory to perform on a specific engine for a specific year. If you swap jets, the carbs may not perform as expected. If I swap carbs, I start with the jets that are in it, then re-jet it incrementally, then water test it briefly. Document the max engine rpm's and observed speed each time. Repeat the process till it peforms well and won't result in a lean-running condition. It's time consuming and expensive, since you have to buy a lot of jets...