Should (and how much) a 2 stroke smoke @ idle? 50:1

[CamaroMan]

Hi all - just curious, when tuning the idle mixture.. i was playing with a 87 50hp this week - i could get it to go from no smoke to a light blue hue to a little too much smoke.. whats best?

Do you tune it from rich in to just where the blue smoke goes away? I saw another 50hp with no smoke and the mixture smelled right (sweetish), but it had no smoke - good comp on both-

So lets say I can get a clean smoke free idle at 1 to 1 -1/4 turn out - would that be fine? im not trying to say theres necessarily a magic number but i would never do less than 1 turn on older 2s motors- im trying to figure out if its possible to tune 2 strokes to run nice and clean with almost no smoke and not be too lean?

Once its mid range the idle circuits no longer operates and im also wondering what effects a leaner (but not sneezing) idle mixture might have on the motors overall longevity?

 

[F_R]

In the first place, you shouldn't be tuning for smoke. Set the idle mixture as lean as possible without sneezing or stalling. You can't get it "too lean" on idle. And no you won't wear it out.

If smoke really is bothering you, consider running 100% synthetic TC-W3 oil. At 50:1 ratio.

 

[racerone]

I guess more proof that oil / smoke / lubrication inside a 2 stroke engine is not well understood.

 

[jimmbo]

That's a new one, 'Tuning for Smoke'... I always went for Best Idle and/or Acceleration. Extra Smoke was a Bonus, kept the Mosquitoes at bay

 

[juno pierrat]

I'm think'n in 87" the carbs didn't have an idle adjustments, got any model numbers? thats my years motor and it don't.

 

[CamaroMan]

guys lol, to clarify- im talking within the margin of being in a good enough setting.. im not troubleshooting but curious about the last minor adjustments.. would a REALLY light smoke still foul plugs? - but ive seen a few melted pistons and was curious, i dont tune for smoke- but i can get it to almost not smoke or smoke VERY lightly - im talking fine tuning scenario.. ive been working on motorbikes and stuff for 20 years.. gee-

87 force and 87 johnson - idle mix screws present..

 

[racerone]

An 87 model 50 HP is not shown with mixture screws from the factory.----A 1987 model 50 HP in good condition does NOT foul sparkplugs !!-----Pistons do NOT melt due to low speed mixture problems either.

 

[juno pierrat]

yep, what he said

 

[CamaroMan]

tx racer.. im more curious to know if a good running well tuned 2stroke smokes or not basically

 

[jimmbo]

tx racer.. Im more curious to know if a good running well tuned 2stroke smokes or not basically

Yes. A lot of racing 2 strokes ran 16:1 and they were well tuned. TCW oils when burnt produce one of the sweetest Fragrances known to exist.

What is your fixation about a little smoke?

 

[CamaroMan]

jimmbo no fixation, just looking to learn something about the carb setting vs smoke @ idle relationship. Title refers to a normal 50:1 mix / regular fuel/use-

 

[Scott Danforth]

2-stroke smoke makes me happy

 

[jimmbo]

2-stroke smoke makes me happy

And smells Sweet to boot:joyous:

We have something else that smells sweet when Smoked, and it also makes one Happy

 

[Scott Danforth]

I was keeping it family friendly jimmbo....

 

[jimmbo]

I was keeping it family friendly jimmbo....

When others have mentioned having a Cool One, or other refreshing Adult Beverage, there was no concern of keeping "Family Friendly".

 

[flyingscott]

It will smoke you own a 2 strk outboard that is what they do. You cannot tune smoke out of a 2 strk. If you do not want smoke buy a 4 strk

 

[Oldnbold]

The way I have always been taught to tune a carb idle jets is by tuning for maximum rpm’s. That’s usually fairly lean. You do run the risk of the cough and sneeze but it’s smokes less and it’s crisper coming off of idle.
This idle will vary with Ambient temperature and operating temperature of the motor which is dependent upon a functioning water pump and thermostat.
A lot of people say turn it to the factory setting but that is a baseline in my opinion.

 

[jimmbo]

There is no Factory Setting(except for carbs with fixed low speed jet(s)). There is an Initial Setting, which is too rich but will allow the engine to start/run. Every engine does leave the Factory with the needle set for best running at the Factory. Most dealers will run the engine and readjust it for local conditions, but the end user should do the final setting. I always found smoothest idle didn't coincide with best Acceleration. I also never worried about the smoke, in fact I welcomed it, as it kept the bugs away