OK....here we go.......The reason to rejet in the winter is because the air is cold and condensed thus more O2 is mixing with the fuel causing it to run lean. You need to rejet to deliver more fuel to mix properly with the more O2 coming in..... to correct the lean condition.
My question is...why cant you turn your air screw in, say maybe a half turn or so to reduce the amount of condensed air so it mixes correctly with the "stock" amount of fuel the engine is getting? Isnt this really the same thing as rejetting? (only kind of reverse).
My thoughts are either 1) increase the fuel (with a bigger jet) OR 2) much easier.....reduce the air mix by screwing in the air screw.
I am pretty stupid when it comes to engines but it sounds logical to me. Would this would for both 4 stroke and 2 stroke engines? I think that maybe the engine may not be a peak power but at least it wouldnt lean out, right?
What do you guys think?

 

LOL........yeh.......it must be my college days are coming back to haunt me [img]i/expressions/face-icon-small-smile.gif[/img]

 

Well your right about the air screw adjusting the amount of air to the fuel mixture.

But the air screw only controls from idle to 1/4 throtle, but it does have a very minor affect on 1/4 and up but not enough to prevent engine damage.

I run my trailblazer at the following:

I run stock jets (in ohio....go bucks) and at 30 to 50 degs(who wants to ride at colder than 30???) I run the air screw at 1/2 turn, at 70 degs I run 1 1/2 turns(stock), and 85 and up I run 3 turns.


Hope this helps


Oh yeah

O.....H......

 

Wishful thinking but it's not quite that easy, the airscrew basically only affects the pilot circuit which controls idle up to approx 1/4 throttle. The amount of air the airscrew controls is small compared to the amount of air that is drawn at higher throttle openings so while it will help you still have to rejet unless you run under 1/4 throttle all the time...

 

Thanks for the replies - told you I wasnt good at engines.....but at least I was partly correct...which means I am learning so thats cool

THANKS!

 

if your running a 2 stroke in the winter then you better rejet. turning the air screw in isnt the answer. you need more fuel beause of the cold air. a 4 stroke has valves to help reduce the heat where a 2 doesnt.

 

Also, depends on whether your talking about a 2-stroke or 4-stroke engine:

A 2-stroke uses an AIR screw, which leans out the idle mixture when you back it out, allowing more air to mix with the fuel before it flows from the pilot jet. It's located closest to the airbox side of the carb.

A 4-stroke uses a FUEL screw. Backing this one out allows more fuel to enter the pilot circuit, richening the mixture. It's located on the engine side of the carb.

Same circuit, but opposite functions.

 

Yep.

I reinstalled my stock filter for less air flow and double-wrapped it in shop rags to further restrict airflow. So I've essentially reduced the amount of air coming in, thereby hopefully richened the mixture a bit. The ATV runs great and I've been plowing steadily for the last four days in about 15 degree outside air temps.

I wanted to install a Dial A Jet but being Christmas time, I've had to put the $70 for gifts and such. I'd still like to try the DAJ but probably in January.

 

didnt think of wrapping the air filter. Have you checked your plug for color after you did that to see if it's runnin right?
I would think wrapping the filter certainly couldnt hurt it at all and only benefit the situation.

 

No, I haven't checked the plug mostly because it's damn cold out! I'll do a plug chop the next time we get a break in the snow fall.