I re-did a few years 75,85,91 9.9/15hp and the cup seal (part#20)was not shown on the 85 and 91 model. I wonder if the 85 91 came with one to begin and if so why they weren’t shown in diagram? The 91 model seemed to be of a better designed carb and better at idling speed than the 75 and 85 models I worked on. A 91 carb would most likely work on a 75-91 with a slight mod possibly to the choke knob an air box on some models but a 91 will bolt up the the air intakes on them I have done it.

I also noticed on all these motors that I had to time the magneto plate to carb correctly to get them to idle well with the carb butterfly not open when it was on the mark on the magneto plate where it rides on the roller that operates the carb butterfly.

I also noticed that carb cleaner would totally mess up the packing piece (retainer needle valve part #21) which was present on all 3 of the carbs I wonder if it messes up the cup seal or (bearing needle valve part #20) like it did the packing piece I am guessing it doesn’t because I didn’t replace the cup seal on any of these 3 motors but I did shoot the carb cleaner down into the hole needle valve screws into to make sure it was clean. I did replace the packing piece on all 3 carbs part#21 which is easy to do even if carb is still attached to motor.

I did work on like a 1995 9.9hp this past winter in Key West. It had the best carb (part#436778) design of any 9.9s Johnson/Evinrude I worked on (IMHO) so far not that I have worked on a ton like many folks reading this. Johnson blocked off the front mixture screw and went with one on the side as you can see how they blocked it off. Their has to be a reason they did that. If you look at the picks on ebay you can see the mixture tube that goes from top of carb to bottom of carb it clam shells to each other when you put the bowl on. I did notice it simplified the way the slow speed fuel got to the engine. I don’t know if it would bolt up to a 75-91 9.9hp air intake manifold bolt pattern but if so a cam follower could possibly be faribricated or attached to this carb it looks like it has a place for one in pics it might be worth the effort especially if it was a daily runner. It by far was the best I worked on as far as 9.9hps go and capable of idling way down with a very consistent idle. The carb on the 1995 part# 436778 I worked on had a choke like the one for sell here on Ebay
http://www.ebay.com/itm/1994-2003-Johns … ni&vxp=mtr

Just My Humble Opions,
Sorry for rambling but I find these 9.9 carbs interesting and how they kept changing them thru the years.
Joe

1975 9.9hp diagram
http://www.marineengine.com/parts/johns … B+Manifold

1985
http://www.marineengine.com/parts/johns … B+Manifold

1991 9.9hp diagram
http://www.marineengine.com/parts/johns … Carburetor

Frank,
Thanks for the help I sure respect your knowledge of outboards. I couldn’t figure out why that cup seal would be present on the 75 carb then not present on the 85 and not present on the 91 but the 91 was way different in its make-up than the 75 and 85. Then on the 95 they totally plugged off the mixture screw on front of carb and put it on the side.

Joe

Retiredoz,

you may be right . I am guessing your talking about the cup seal being not used in 79? I do know that it seems like the carb was changed 3 times in a serious way for basically the same power head that was used on 9.9s from like 75 to 91ish to 95ish other than the ignition systems going from points in the 75 then 85 and 91 were also different from each oher I am guessing both were a type of cdi type set-up for 85 and 91. I couldn’t tell much of a difference when setting up the motors regarding ignition systems other than getting the timing of the carb butterfly opening at the correct time with relation to the magneto plate rotation. The big difference to me on slow engine idle was how well the 95 carb performed much better than the 75 85 and 91 carbs.