Running a bit rich at idle? mixture screws???

joetheis

Petty Officer 1st Class
Joined
Apr 21, 2014
Messages
308
This is on a '91 Evinrude 70 HP with VRO.
Last fall I purchased the boat, ran crappy on the bottom, 1500 rpm and stuck there. I didn't have time to tinker with it on the water before I brought it home.
Got it home, found out the thermo was stuck open, so it was running cold.
New impellar, new thermo, plugs, wires, link and sync the carbs. spin on fuel filter added, new fuel and oil tank lines, lower unit serviced.
On the oil tank, cleaned the tank, new sock, new oil.
Tank was filled with non ethnol gas, sea foam, sta-bil, valve tech.
I adjusted the mixture screws, (with the ear muffs on), and I THINK I set it a bit rich, but time and age has my mind in a fog. Had it running nice.
The boat is 230 miles away, so I have 2 weeks before I go up the think about all this.
It seemed to be good off idle.
Seems to develop a rough idle, motor is "jerky", a bit of a sputter. a bit of smoke at idle I noticed idling at the dock when I came in.
Ideas?
I turn the mixture screws In to lean out to richen?
(I do it on the water, so I don't want to poke and hope, just adjust)
Thanks!
Joe
As you get older, you forget more........... As you get older, OH,!! I already said that!
 

175se

Petty Officer 1st Class
Joined
Mar 6, 2014
Messages
274
Know the feeling, in is leaning the mix, out richens the mix.
 

joetheis

Petty Officer 1st Class
Joined
Apr 21, 2014
Messages
308
Tanks!
I had the idea it was backwards assed, as I THOUGHT it was air jet, out leans.. (who knows why I thought that).
Good thing I be a askin!
I just don't want to be leaning over the boat in the water or sitting on the dock zipping screws in n out!
Somewhere I read these 3 cyl 70's have the "jerks" at idle?? True?? or can I tune it out to a smooth idle??
Joe
 
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