1983 Johnson 35 low speed carb adjustment moving due to vibration.

[scipper77]

Title pretty much says it all. I was out yesterday and I dialed in the low speed knob on the water. I had things adjusted to where I could idle at the slowest speed in neutral but in gear the slower speed would cause a stall. The boat seemed a little rough in gear at mid throttle. Lots of vibration like maybe only 1 cylinder was hitting. Full throttle was smooth and powerfull. I pulled the cowel to see what I could and eventually figured out that the knob was turning from the vibration of the motor. I did pull the carb last year due to a stuck needle and seat. Is it possible I assembled it wrong? The motor runs well when adjusted properly.

 

[steelespike]

Idle speed needs to be about 700 in gear.Adjust mixture in gear underway. Usually better to be slightly toward rich. There may be a a packing nut.Snug it up just enough the hold the adjustment.

 

[Chinewalker]

Carbs of that era have a rubberized plastic piece that fits in the keyhole area around the needle valve. As they age, they harden and lose their ability to produce friction on the needle shaft. New ones are included in most carb rebuild kits...

 

[Joe Reeves]

1983 what?

 

[AlTn]

1983 what hp?...is it the idle mixture needle vibrating out of adjustment or the idle speed adjustment vibrating out?..ok 35hp... see Chine's reply...the plastic piece he refers to can be so "tough" that it's easier to put the needle in a vice and screw the carb body onto it rather than screwing the needle into the retainer

 

[scipper77]

Sorry, It's a 35 horse. There is one knob on the front for adjustment by hand. I believe this to be the low speed jet, not the idle adjustment.

I'm tempted to just rebuild the whole thing as this motor is new to me last year and has very low hours. But, I'm not a huge fan of messing with things for no reason.

 

[racerone]

????------The part that you need for the slow speed needle is listed at $2.19 , so why are you looking at rebuilding the whole thing ?????

 

[scipper77]

????------The part that you need for the slow speed needle is listed at $2.19 , so why are you looking at rebuilding the whole thing ?????

OCD, if I have to take things apart I might as well spend a little bit of time making sure some other part doesn't fail next. The low hours on this motor means it's likely that everything is original in there.

It looks like the part I need wouldn't require anything more than removing the needle, replacing the part, and setting the carb up again starting at 1.5 turns out etc..... Not going to rebuild in this case because the carb doesn't need to be removed.

I believe we are talking about part #28 in the diagram. Can anyone confirm that this is what I need.

 

[AlTn]

that's it