10 sizes should reward you with a block of melted aluminum. If it would even run at all.

Open the following link and check line # 26 for jets used.

https://www.skidooparts.com/oemparts/a/ski/500c5056f87002314436f3e0/carburetors-443-503

Be sure you have the correct needles, needle jets, needle and seats and the needles are in the correct position.

I would drop two sizes and try it providing everything is as and where it should be. Baby steps!

Lynn

 

10 sizes should reward you with a block of melted aluminum. If it would even run at all.
Open the following link and check line # 26 for jets used.
https://www.skidooparts.com/oemparts/a/ski/500c5056f87002314436f3e0/carburetors-443-503
Be sure you have the correct needles, needle jets, needle and seats and the needles are in the correct position.
I would drop two sizes and try it providing everything is as and where it should be. Baby steps!
Lynn

10 sizes should reward you with a block of melted aluminum. If it would even run at all.Open the following link and check line # 26 for jets used.https://www.skidooparts.com/oemparts/a/ski/500c5056f87002314436f3e0/carburetors-443-503Be sure you have the correct needles, needle jets, needle and seats and the needles are in the correct position.I would drop two sizes and try it providing everything is as and where it should be. Baby steps!Lynn

What do you mean by 10 sizes? The parts are only the baseline jetting, I have a table for a 98 which I think should be the same as a 99 giving me options for other temperatures. Just confused why a smaller engine runs with bigger jets. This is what I'm leaning at for jets.

0-2000' is not the range I'm riding in, it's just the bottom range I'm use to seeing in calibration tables. I start at around 700' and would peak out a little over 2000'. I'm looking at the 0-2000' jetting for safety but playing the altitude against the temperature between the -4 rating and 14 rating. Somewhere in that range is what I'm looking at. I was thinking either start at 190/180 or 185/175. They both seem to be suitable under most conditions. This machine also pulls a drag at 10-15mph and will be geared down behind factory spec so it can get farther into the clutches to stay in the powerband at a slower speed.

 

What is the correct main jets to run in a fan cooled 440 for 0-2000' and say 0 deg f and above. I am stumped?
I just got done fighting with float heights that we're too high and that solved the problem a little but the temp was colder. My wife and I just went out. She was on a formula dlx 500 fan and it was fine, I was bogging like I was doing the other day in the high 20's before I adjusted the float. Both are 99's the 503 is in a formula dlx and the 443 is in a touring le.
I checked the manual and the 503 fan is jetted 180/170 and the 443 fan is 205/195. There must be an error in the table how can this be right?
Where should I move the jetting to. The way it is now is completely unrideable and I'm using the touring to groom with so I'd like to get it sorted out and get a good middle of the road jetting safe to 0 deg f but will still be rideable in the high 30's or low 40's
Can I go 10 sizes smaller than the 503 and be safe? I can't figure out why a smaller engine is getting more fuel dumped down its throat.

I guess I said that wrong. By 10 sizes I meant 170/160. 10 numbers less than the 503 baseline jetting. The big question here. Why does a 440 have bigger jets than a 500?

 

The 503 and the 443 both have 34 mm carbs. The amount of fuel that goes into the engine depends on how much air the engine pulls. The 503 pulls more air than the 443 does so it is actually getting more fuel through a 180 jet than the 443 pulls through the 200 jet. It is not just the volume of air but the air speed through the carb that affects the volume of fuel, so also depends on intake port timing as to how much fuel it can pull through a given jet.

Also the efficiency of a pipe on a given engine will change how much fuel is pulled into engine.

 

The 503 and the 443 both have 34 mm carbs. The amount of fuel that goes into the engine depends on how much air the engine pulls. The 503 pulls more air than the 443 does so it is actually getting more fuel through a 180 jet than the 443 pulls through the 200 jet. It is not just the volume of air but the air speed through the carb that affects the volume of fuel, so also depends on intake port timing as to how much fuel it can pull through a given jet.

I never thought of it that way. I guess it needs a bigger port to slobber it out of since the vacuum signal is less. It's strange that the standard calibration is 200/190 but then the preferred -20F table is 205/195. I wonder how much cushion skidoo specs in their jetting table. I personally am a Yamaha guy and just getting into older Doo's. The Yamaha jetting didn't have an inherent cushion for temp. If it was colder you were lean.

Going down one size from standard calibration to 190/180 should be safe starting point to ride it and read the plugs?

How likely would I be to find a cracked fuel pump diaphragm? There is no indication of pooling fuel in the bottom end on cold start. In fact with full choke cranking is 5-10 seconds to get first fire and it's a healthy battery cranking fast.

 

The 503 and the 443 both have 34 mm carbs. The amount of fuel that goes into the engine depends on how much air the engine pulls. The 503 pulls more air than the 443 does so it is actually getting more fuel through a 180 jet than the 443 pulls through the 200 jet. It is not just the volume of air but the air speed through the carb that affects the volume of fuel, so also depends on intake port timing as to how much fuel it can pull through a given jet.

Also the efficiency of a pipe on a given engine will change how much fuel is pulled into engine.

Well explained.

I would take the jetting down one size and test the sled for the result. As I said before 'take baby steps'. Do check for the correct needles and settings, needle jets and the correct size needle and seats. There is more to calibrating a carb than just a main jet change.

Is this sled something you have had for a while or recently aquired? Has the engine always run too rich or has this come on recently?

Lynn

Edit: To answer another question, Ski Doo always jets their carbs on the rich side from the factory. Settings are for sea level. This also gives them some protection while the sled is new and under warranty. Take a new sled to your dealer with a melted down piston and they find the jets have been changed and your warranty can be instantly voided.

 

Well explained.
I would take the jetting down one size and test the sled for the result. As I said before 'take baby steps'. Do check for the correct needles and settings, needle jets and the correct size needle and seats. There is more to calibrating a carb than just a main jet change.
Is this sled something you have had for a while or recently aquired? Has the engine always run too rich or has this come on recently?
Lynn

Edit: To answer another question, Ski Doo always jets their carbs on the rich side from the factory. Settings are for sea level. This also gives them some protection while the sled is new and under warranty. Take a new sled to your dealer with a melted down piston and they find the jets have been changed and your warranty can be instantly voided.

No. I recently acquired it from a kid in his early 20's who flips sleds, dirt bikes, atv's that kind of stuff. He had sold it once and the seller brought it back because it was doing this intermittent rich bog.

I have since checked the needle jet, pilot jet, main jets & given the carbs a 1 hour chem dip bath then put in new 1.5 needle and seats. The needle jet is a 159 P-0 the pilot jets are #35's. The needle is in the 3rd clip but I haven't been able to verify the part number.

Upon reinstalling I reset the float height. They were way too high at 3/4". The air gap is set at 1.6mm and the carbs are synched. The chokes are checked and within spec.

I test rode it after the reinstall and it ran great. Temp was in the low 20's at night. Got right up and scooted. I got up to 45 before running out of field.

Yesterday running it at 47 deg f it was so rich it was bogging again. I'm trying to find a better set of middle of the road jets.

My starting altitude is 700' and we max out a little over 2000'. I just don't need jetting for -20 deg f at sea level. I was leaning towards 190/180 or 195/185 based on my altitude and desired temp range. The machine is also being used to pull a drag in the 10-15mph range and I have purchased gears from a 2001 skandic 440 so it will be geared down more to 18/44 so that the clutches are farther shifted out and being higher in the powerband.

I'm not opposed to having to do an early season/late season jetting change I am just hoping to figure it out now, at least the spring jetting.

How reactive is a 5 change vs a 10 change? Like going 205 to 190 vs 205 to 195?

 

Now that you have the engine running better you didn't say if you changed the jets to a leaner number or if they remain the same. If I change jets in a stock engine I go one full size. Half sizes are hard to find if you can find them at all. If it warms up I like a little added fuel to help cool the engine even if it is a small power loss.

Lynn

 

Now that you have the engine running better you didn't say if you changed the jets to a leaner number or if they remain the same. If I change jets in a stock engine I go one full size. Half sizes are hard to find if you can find them at all. If it warms up I like a little added fuel to help cool the engine even if it is a small power loss.
Lynn

It ran better in the low 20's with the new needle valves and the float height set correct. It still has the 205/195 jets because none of my tuning jets have come in the mail.

In the low 20's being jetted for -20f was ok. At 47f it was unrideable rich.

 

Your lawnmower would be rich in 47 deg. F temps. LOL

Lynn

 

Your lawnmower would be rich in 47 deg. F temps. LOL
Lynn

That's where I'm trying to figure out my starting point. Either 195/185 or 190/180 and my altitude falls in between those two ranges and I would be tending to be running it in warmer temperatures not colder.

 

I'd go with 195 / 185 if you can get them and keep an eye on the plugs. No all out runs until you're satisfied it's not too lean. If you're pulling something I'd stay on the rich side especially as the weather warms. When you're working with these smaller jets a small change has more effect than it would with a larger jet.

Honestly at 47 I'd park it. Much over 40 and I sweat more than the sled does. I'm waiting for that tinky, tinky bang! Then my dealer's cash register goes "Ka Ching".

Lynn

 

Tug, when you are trail riding that rig or pulling your groomer are you running at 3/4 or more throttle open ??

 

Tug, when you are trail riding that rig or pulling your groomer are you running at 3/4 or more throttle open ??

It takes half to 3/4 to accelerate then I ease up and am able to ride at 1/4 to 1/3 depending on the conditions of what I'm pulling. Gets up to 1/2 steady sometimes on a larger hill or harder snow.

 

I think I know where 396F/A is headed but he's got the floor.

 

Tug, the following is in no way intended as me being a smart azz or making it look like you don`t know, that is the farthest from the way it is. Some fellows get up-set when you tell them some thing they already know, thats not what this is intended for.

At times it seems like a fellow may not fully understand some thing and a little help might be good. I am no expert, that is for sure.

A few post back you posted a jetting chart, you will note that in the first section, there is no change in any jetting until 6,000 ft ( regardless of temp) then at 6000 you drop the needle one notch and close the idle air a bit, that is good until 10,000 ft, then one more notch drop on the needle. The mid range jet ( needle jet or emulsion tube what ever you like to call it does not change at all or the actual needle ) About all sleds ( Doo, Yammie, Polaris, Cat ) are the same, no mid range changes needed. ( for trail/pleasure riding ). The factory guys are a lot smarter than some like to give credit to . They set the pilot, idle air, slide cut away, needle jet, jet needle and clip to handle a wide range and usually they shoot for the mid notch for the needle clip for adjustability. All those components working together control the fuel delivery to the engine almost totally up to 1/2 throttle and still some control up to 3/4 throttle. In theory you could take your Touring LE and install 500 main jets, ensure all other setting are to factory specs and the sled would run just fine ( not rich) up to 1/2 throttle.

Because the factory guys have done a good job of mid range jetting and the nature of the beast we seldom need to make any changes to the mid range jetting. We do need to change mains for optimum performance at the top. So due to this, that is all we know and get hung up on fixing our jetting by changing the main jets. It is not uncommon for a fellow in your situation to keep seeing rich running, keeps going down sizes on the main jet but is running at low throttle opening, then some day he sees a nice mile long table top and opens er` up, soon he hears the dreaded blaaaahhhhhhhh, OH kaw kaw.

We buy used sleds or used carbs etc and really have no idea what has happened to them in their life. How do we know if at some point the needle jet was kinda dirty so Einstein decided to clean it up with a twist drill bit. . It don`t take much of a difference in the ID of the needle jet to make a difference. I The change from a 159 P0 to a 159 P2 is 5 - 8% more fuel delivery at 1/3 - 1/2 throttle, ( I am not looking at manual right now and can`t remember the actual size diff from P0 to P2 but it aint much).

My point is I think you are trying to fix low speed rich condition with high speed changes.

If you are confident that your fuel pump is not leaking into the crank case, you choke plunger ( enrichers) are fully seated and holding etc...Some might jump on me for this but try raise the needle clips one notch ( drop the needles) and try it, but be careful and check the plugs soon and frequent at first. I think that is a band aid but you can give it a try. If that fixes it you might want to invest in a new set of needle jets. Rule of thumb, one clip notch on needle is ~ one needle jet size.

Good luck with your unit Tug.

 

Bingo. Very well done. I had a hunch you were going to suggest dropping the needle to clean up the mid range after reading your previous post. Your explanation was very well done.

Lynn

 

Tug, the following is in no way intended as me being a smart butt or making it look like you don`t know, that is the farthest from the way it is. Some fellows get up-set when you tell them some thing they already know, thats not what this is intended for.
At times it seems like a fellow may not fully understand some thing and a little help might be good. I am no expert, that is for sure.
A few post back you posted a jetting chart, you will note that in the first section, there is no change in any jetting until 6,000 ft ( regardless of temp) then at 6000 you drop the needle one notch and close the idle air a bit, that is good until 10,000 ft, then one more notch drop on the needle. The mid range jet ( needle jet or emulsion tube what ever you like to call it does not change at all or the actual needle ) About all sleds ( Doo, Yammie, Polaris, Cat ) are the same, no mid range changes needed. ( for trail/pleasure riding ). The factory guys are a lot smarter than some like to give credit to . They set the pilot, idle air, slide cut away, needle jet, jet needle and clip to handle a wide range and usually they shoot for the mid notch for the needle clip for adjustability. All those components working together control the fuel delivery to the engine almost totally up to 1/2 throttle and still some control up to 3/4 throttle. In theory you could take your Touring LE and install 500 main jets, ensure all other setting are to factory specs and the sled would run just fine ( not rich) up to 1/2 throttle.
Because the factory guys have done a good job of mid range jetting and the nature of the beast we seldom need to make any changes to the mid range jetting. We do need to change mains for optimum performance at the top. So due to this, that is all we know and get hung up on fixing our jetting by changing the main jets. It is not uncommon for a fellow in your situation to keep seeing rich running, keeps going down sizes on the main jet but is running at low throttle opening, then some day he sees a nice mile long table top and opens er` up, soon he hears the dreaded blaaaahhhhhhhh, OH kaw kaw.
We buy used sleds or used carbs etc and really have no idea what has happened to them in their life. How do we know if at some point the needle jet was kinda dirty so Einstein decided to clean it up with a twist drill bit. . It don`t take much of a difference in the ID of the needle jet to make a difference. I The change from a 159 P0 to a 159 P2 is 5 - 8% more fuel delivery at 1/3 - 1/2 throttle, ( I am not looking at manual right now and can`t remember the actual size diff from P0 to P2 but it aint much).
My point is I think you are trying to fix low speed rich condition with high speed changes.
If you are confident that your fuel pump is not leaking into the crank case, you choke plunger ( enrichers) are fully seated and holding etc...Some might jump on me for this but try raise the needle clips one notch ( drop the needles) and try it, but be careful and check the plugs soon and frequent at first. I think that is a band aid but you can give it a try. If that fixes it you might want to invest in a new set of needle jets. Rule of thumb, one clip notch on needle is ~ one needle jet size.
Good luck with your unit Tug.

No offense at all. Honestly I wish someone was close enough to me to come and take a look at it. I am back at work now and I certainly can try dropping needles when I get home if I still have snow. I feel that I do need to jet down some but I can drop the needles and see what happens.

I did pull the jet needles out when I dunked the carbs and they were 159 p-0's bit as you said there is no knowing what someone did. They did not have any evidence of drill scrapes but that doesn't mean anything. Maybe the needle clips will finish out this season and I can buy new genuine needles and jet needles to install over the summer and it has brand new parts for next year.

 

Well I just decided to get it over with, I ordered new 159 P-0 jet needles and 6DH2 needles. I also have main jets on the way with sizes from 200 down to 160 in 5 increments so I will have everything available to play with. Given the suspect of someone drilling out the jet needles during cleaning I'm not going to trust that the 205/195 mains are the correct size anymore either.

If I'm going back into the carbs I'm going to know that I have all new parts when trying to tune it next. Winter is short and snow is prescious. I'll set them up with 200/190's which is book and brand new parts on the 3rd clip and go from there to see what we have.

On an air cooled engine is a spark plug with the electrode burned half way through the bend still considered safe or is that not enough extra cooling fuel?

 

Time for new plugs too.

Lynn

 

Time for new plugs too.
Lynn

Is there a rebuild kit that's of good quality or a suitable pump to replace the stock one? If I do all the carb parts and I still have the problem I'm down to just the fuel pump. The doo part no is NLA so looking for options to either rebuild or replace.

 

Is there a rebuild kit that's of good quality or a suitable pump to replace the stock one? If I do all the carb parts and I still have the problem I'm down to just the fuel pump. The doo part no is NLA so looking for options to either rebuild or replace.

I would do the carbs before worrying about the fuel pump. If you have a dealer nearby who buys from WPS (Western Power Sports) they show a pump available for your '99 Touring LE. Verify this with your dealer though as the listings in the catalog aren't always correct. Take a picture of your pump with you.

I highly doubt your issue is caused by a faulty fuel pump.

Lynn

 

I got it sorted out. I put in new needle jets. When I had new parts to compare with the old parts I could see they had been drilled, not a lot but just enough.

Thanks for the help everyone.

 

Great that it looks like you found the issue :Cheers Can`t wait til next winter to try it out huh !!!

 

I got a whopping 6 miles in! We got some last minute snow up in the mountains about an hour from my house so I took a ride! It runs good, the idle was hanging I had the floats lowered when I was chasing the rich bog so it had a bad idle hang and the plugs were in my opinion a little lean. I would consider them safe if I was close to zero but I was at 20F. I adjusted the floats so the arms were just resting at the correct height instead of hard against the anti chatter spigots.

I also got a 17T top gear from a 440F skandic so I will be very effectively geared down from 21/44 to 17/44. The primary market test doesn't have me close enough into the shift range I would like to be for pulling.