How much choke smoke is normal?

[Gonzo]

I get quite a bit of choke smoke and it keeps my transom nasty, how much is normal? I adjusted the 4160 carb choke mixture screws all the way down and then 3/4 out (1.5 turns is what the manual says but its WAY too rich). The only way to keep the smoke to a min is to screw them all they way in, but then it is hard starting cold and someone told me I may burn up the rings...

any and all advice welcome.

[Bellinghamster]

Is the choke all the way open when the engine is warm? If not, check to see it's got 12V on the terminals when the engine is running and that it's properly adjusted. If it still doesn't open when warm, then replace the electric choke

If the choke is opening fully, then sounds like a carb rebuild is needed. Rich mix can be caused by high float level (misadjusted or leaking float valve) or blown power valve (vaccuum actuated valve that richens mixture when vaccuum reaches a certain leve. If the power valve diaphram is torn, it'll stay open all the time causing rich idle - not dying when the idle mix screws are turned all the way in is aclassic symptom). If properly set up a 4160 should start to stumble/misfire if the screws are turned in more than 1 turn out.

[JimN]

When it's cold (and the air temperature isn't really high), remove the flame arrestor (this is clean, right?) and turn the key ON. The choke should be closed but if it isn't, move the throttle so it does close. Watch the choke plate and see how long it takes to open. If it takes a long time (more than a couple of minutes) or doesn't open automatically over that time, you need a new choke thermostat.

Those are idle mixture screws. You shouldn't have smoke at any time, really. Make sure the flame arrestor is clean.

[TMCNo1]

I've lived with it from day one! It easily washes off when in the water and when it's just been loaded on the trailer using a damp towel. You can see it on the beige part of the transom, under the platform a couple of hours after launching at CSM '08 and it all came off two days later when we loaded the boat to come home Sunday, I just live with it! My choke comes completely off when I give it full throttle out of the hole shortly after launching, about 5 minutes. It never engaged again at CSM '08 cause the engine stayed warm overnight and all I did the next two mornings was just hit the switch and she cranked.
Have I ever said, "I love the smell of Carbon Monoxide on Carolina Spring Morning"!
38563

[Skipper]

I get quite a bit of choke smoke and it keeps my transom nasty, how much is normal? I adjusted the 4160 carb choke mixture screws all the way down and then 3/4 out (1.5 turns is what the manual says but its WAY too rich). The only way to keep the smoke to a min is to screw them all they way in, but then it is hard starting cold and someone told me I may burn up the rings...

any and all advice welcome.

This is how I always adjusted my 4160 carb. It resolved my black smoke problem.

These instructions are cut and pasted directly from the SKIDIM FAQ page:

HOLLEY CARB ADJUSTMENT INSTRUCTIONS

1. Rev up the engine to clear it out.
2. Turn air screw in until you hear engine begin to bog and miss.
3. Now, turn screw out with 1/2 increments until you hear that the engine is steady and running smoothly.
4. Repeat procedure on air screw on opposite side of the metering block.
That’s it!

Whether it adjusts only the idle it works. Try it.

[TMCNo1]

One of the contributing factors to the choke smoke is, according to my owners manual for a carb'd engine is, "Cold start, Prime the engine by pumping the throttle 2 or 3 times in neutral prior to cranking". This extra gas for priming in addition to the choke being on, makes a nice rich little recipe for creating some choke smoke.