Acrid exhaust w Ranger 400 - carb setting?

My brother has a new one and it is the same way. I don't know what the deal is with that.

Check your plug and see if it's rich. With the cooler denser air it's Prolly running a little rich

yah i agree with jayce on this, hwoever i wouldnt worry about it...rather have that mother runnin so rich it burns your eyes instead of so lean it burns your cylinder..just my 2 cents. keep a spare plug handy...they're cheaper than pistons and valves!

Pionier said:

Hey fellas,

Wondering if anyone else notices this with the carbed 400's: The exhaust is so acrid it brings tears to your eyes! We had a decent snowfall up here and, like any red-blooded male with two kids and a recovery strap would do, decided to wake-board behind the machine on a kid's toboggan today (wife driving, God bless 'er). Yes it was fun and no I don't care what you think about safety. I found the stink behind the Ranger to be worse than any old 2-stroke sled. Question is: are we simply spoiled by catalytic converters and "unscented" exhaust or, do I have a carb setting that needs attention? I run premium gas, with stabilizer/Seafoam on occasion. Thoughts?

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Jeff, what year is your Ranger? I haven't noticed any smell from my 2011 500. It run almost exclusively Shell premium in it.

My 2011 400 has been the same way since I bought it, I've changed the plugs regularly, cleaned the carb, ran premium gas and sea foam too and no change. It's really noticeable when the vehicle is running and I have to do something behind it like put the hitch on. Once I was using the Ranger to move boxes outta my houses front door to the shed and I left it running and it was so bad my carbon monoxide detector in the basement went off. Guess thats just how the carbed ones are. FWIW I too use the Ranger to pull people around in the snow, the kids have a blast, I do make them wear ski helmets though.

revrnd said:

Jeff, what year is your Ranger? I haven't noticed any smell from my 2011 500. It run almost exclusively Shell premium in it.

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Those are two very different machines.......a carb'd 400 and an EFI 500. EFI will automatically adjust the fuel mixture.

Wagz a machine that's running way too rich will fuel wash the rings out. Yes it's better to run rich than lean but too rich will cause the same amount of damage.

littlebigrancher said:

Wagz a machine that's running way too rich will fuel wash the rings out. Yes it's better to run rich than lean but too rich will cause the same amount of damage.

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yah true. i guess thats where ya keep an eye on your oil though and see how rich of gas it smells. im sure if it was that rich he'd have fouled plugs all the time though dont ya think?

Not necessarily. I would definitly try leaning it out a tad and put a new plug in and see what I does. You should not be smelling fuel that bad.

Cooler air = leaner. So I wouldnt suggest jetting down. They dont smell pretty to begin with. But some of your smell could be from the Premium. More additives in it and burns better with a higher compression motor. Wich our rangers are not. Not trying to start a octane debate...just saying where some of the smell may be comming from.

RJ said:

Cooler air = leaner. So I wouldnt suggest jetting down. They dont smell pretty to begin with. But some of your smell could be from the Premium. More additives in it and burns better with a higher compression motor. Wich our rangers are not. Not trying to start a octane debate...just saying where some of the smell may be comming from.

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Rod, I run premium (and Jeff probably does too) because in Ontario, Shell's premium is ethanol free. Even though my small engines don't req' it, I run it across the board, since the gas can may sit around before it's refilled.

Kris, I hear where your comming from. I used to run the Temiskaming Abitibi trail system a couple times a year through the winter. Fuel could be iffy at times depending on where i fueled up. Take the ranger up to the cottage once a year also. I do notice a different exhaust smell from my machines while running up there. Was just pointing out the smell may be more of a fuel additive issue than a jetting issue. My old 04 Ranger was jetted pretty lean from the factory.

RJ said:

Kris, I hear where your comming from. I used to run the Temiskaming Abitibi trail system a couple times a year through the winter. Fuel could be iffy at times depending on where i fueled up.

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:encouragement:

I was looking @ the TATA trail map last night updating my snowmobile lodging database.

revrnd said:

Rod, I run premium (and Jeff probably does too) because in Ontario, Shell's premium is ethanol free. Even though my small engines don't req' it, I run it across the board, since the gas can may sit around before it's refilled.

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True, almost all 87 octane fuel on Ontario is cut with undrinkable corn liquor, so my small engines run premium with Sta-Bil.

My 400 is a 2011 and has always started up best at -5 to +10C, without choke, or below that with full choke. Warm-weather starts require the ranger two-step, and I clean the plug twice a year (shows on the rich side of normal, but not fouled by any means). I also don't stomp the guts out of it as much as it deserves. It doesn't backfire on me, like a rich mix might.

I haven't dug into the Mikuni manual, but getting a leaner mixture involves more than turning a set-screw, I imagine? Pardon the ignorance...all my other carbs (Stihl, Yamaha) have external settings.

Pionier said:

I haven't dug into the Mikuni manual, but getting a leaner mixture involves more than turning a set-screw, I imagine? Pardon the ignorance...all my other carbs (Stihl, Yamaha) have external settings.

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The Mikunis use a jet needle, needle jet & main jet to calibrate the air/fuel mixture thru the throttle range. Not as simple as a quick carb adjustment. I know in the VM series of carbs there are quite a few variations/sizes of these components. Not sure which series of carb is used in the Ranger nor the availabilty of tuning parts.

To the gear heads out there, does Polaris have any jetting suggestions for varying temps or altitudes? Or just a 1 size fits all tune? I don't think the altitude @ the OP's location is all that different from that of Roseau MN.

If it's just a tad outta wack I don't see why you couldn't play with the air/fuel mixture screw to fine tune it to where you like it.

littlebigrancher said:

If it's just a tad outta wack I don't see why you couldn't play with the air/fuel mixture screw to fine tune it to where you like it.

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Other than an idle adjustment screw, what "external" adjustments do the carbs have?

In the 70s Bombardier's Tillotson carbs for the ski-doos had both external low & high speed adjustment screws on the carbs. In light of folks leaning out the high speed screw (w/ the resultant engine seizures) Bombi revised the high speed adjustment to a fixed main jet behind a brass plug.

UPDATE:
I dug up my manual & see the Mikuni is a "butterfly" type. The main & pilot jets can be changed. There is a setting of 2.5 turns out for the Pilot Mixture Screw. No mention of a "air/fuel mixture" screw in the manual.

Pilot mixture...air fuel....just depends on who ya ask. Mine on the 04 was on the bottom of the carb. Looking at the parts fiche for the 11 Id bet it is on the side because of the pilot jet location in that particular carb. The adjustment screw wont show up on the fiche because its under a brass plug you have to remove to do any adjustment. If you want to know how to pop the plug out of there let me know.

I have a 2014 400 with no issues like that.