Hello, just recently purchased used an 04 Arctic F7 / EFI and under the hood by the front there is a connector that says leave connected for regualr fuel, disconnect for MTBE, Ethanol or other oxygenated fuels. My question is what type of fuel do I put in when I run with it connected? Because regular fuel at the pumps say may contain up to 10% ethanol, and then silver is 5% ethanol and then premium gasoline is 0% ethanol. I'm basing this from what the pumps say at SHELL.

Basically when I bought it I was told regular gas leave it connected and Premium gas disconnect it.

Thanks in advance.

Just leave it disconnected all the time... there is no point to having it connected unless you are worried about 0.0001 mph and 0.004 mpg... :p

the only time I ever connect that is when I ride in the warmer temps... the Above zero (for the canadians)

not worth taking the risks with blowing up your motor by forgetting to disconnect it when its either really cold or you get gas with ethanol in it.

Quoted directly from the 2003 Arctic Cat service manual:
Recommended Gasoline for EFI models.
"The recommended gasoline to use in these snowmobiles is 87 minimum octane regular unleaded. In many areas, oxygenates(either ethanol or MTBE) are added to the gasoline. Oxygenated gasolines containing up to 10% ethanol or up to 15% MTBE are acceptable gasolines. Do not use gasolines containing methanol.
NOTE: When using the recommended gasoline(above), the Fuel designation connector at the ECU must be connected.
NOTE: When using oxygenated gasolines (over 10% ethanol or over 15% MTBE), the Fuel designation connector at the ECU must be disconnected.
When using ethanol blended gasoline, it is not necessary to add a gasoline antifreeze since ethanol will prevent the accumulation of moisture in the fuel system.
Do not use white gas or gasoline containing methanol. Only Arctic Cat approved gasoline additives should be used.

I myself have ran gasoline containing 10% ethanol with the fuel designation connector-connected, and never had problems...However I usually fill up with premium, which contains no ethanol. Use the switch as the manual states...don't leave it disconnected at all times. It's there for a reason.
If you ever use a dry gas to prevent moisture, make sure it is Isopropyl based dry gas. DO NOT use any dry gas containing methanol.
I personally use NAPA brand dry gas (MAC's) its a 99% Isopropyl alcohol based dry gas. Be careful witch bottle you grab though because they also sell a methanol based dry gas....just read the label before you grab it. :thumbsup:

why bother?

Well seeing as it's a "04 sled, and a couple of the "04 tunes they used had a very rich fuel map at low/mid range, that would only make it that much richer if it happened to have one of those tunes.....Better keep a box of plugs handy!
Why wouldn't I use it....Cat put it there for a reason....if it was "ok" to just run the sled in ethanol mode for ever, don't you think they would have just done so and not had a switch at all?
So if you had a carbed sled with say a 400 main jet stock-for regular gasoline....but you were running the recommended 410 jet for ethanol..you would just run the 410 jet with regular gas too? Wouldn't bother to change back to the 400 jet?
I'm pretty sure manufacturers design things for reason's. If they could use a 410 jet for both gas and ethanol..wouldn't they put it that way from factory.....same goes for the switch...If it was ok to be left in richer-ethanol mode at all times..would they have put a fuel designation switch in???
Or is it just me? :lookaround:

No I would not bother changin jets... You never know what Kinda of gas you are going to be forced to use out on the trail...

Myself nor my 4 friend who all own 04 and o5 firecats and one who has a crossfire 7 have ever had a plug foul... You are saying you foul plugs? I think my buddy robbie fouled ONE set of plug because he was running it unplugged in +5 degree weather.

Especially for someone who doesnt know or is not great at remembering, unplugged is always better than plugged in... You can toggle it if you like to get that extra little umph with the throttle response, but I would definatly suggest unplugged rather than plugged in if you dont know what you are doing. and if its -20 i dont care what type of fuel you are using, if you are crossing a lake, I would leave it unplugged just because the 700's like to squeeze shut when its really cold. :)

thats just my 2 cents... you can do what you feel is best obviously.

No I've never fouled a plug in my F7. But my ECU was remapped to a 04 tune before I got it. My sled certainly gets gargley and loaded up a bit if I get holed up in a tight trail for too long. I would haveta think having it in ethanol mode would only make the problem worse off. On a lake..I'm fine. I have ripped across the lake many times in regular gasoline mode, never had a problem. I've ridden it in a variety of temp ranges and the sled acts the same reguardless of temp. In tight trails I will get loaded up, unless I can crack the gas now and again to clear it. On lakes....she FLIES with no problems!
You say for someone who will forget or doesn't know what they are doing... What do you mean?
Someone will forget they are putting ethanol/MTBE in there sled rather than regular gasoline? I would surely hope not..... You can run in regular gasoline mode with a 10% ethanol blend or 15% MTBE blend without doing any harm, what is there to forget? Either you use regular gas or your using ethanol/MTBE. Ethanol and MTBE are so hard to find (around here anyways) I highly doubt a gas station found on the trail would only have oxygenated fuels available.

What do you mean by the 700's like to squeeze shut when its really cold. I've ridden in below zero temps and it's never been a issue. What's "squeezing shut'?
I dunno, your more than welcome to do what you want..I just dont understand your logic behind it. It's not saving your sled from blowing up by running it that way.

Running Heat in the red package always works for me. Cat says to NEVER run the Heat treatment in the yellow package. Just what i ve been told.

All the switch does is moves your timing 2 or 3 degrees and lets it run a little cooler. I usually switch to ethanol the minute I get north of the Mackinaw bridge,,, based simply on the fuel. It doesnt matter the temp. I also run nothing but regular gas as that is what the manual calls for. All the premium does is costs you more $$$. I have compared mileage (while trying to run trails) and there was NO difference at all. I have also ran radar and there was NO difference there at all. Why waste the money?? You stand a much better chance of getting bad gas when you buy premium as it usually is the oldest in the tanks. Most people run regular in their cars and trucks and the gas station go through it the fastest.
This leads me to ask,,,, Why are you spending more on your gas for premium???

When I do run the switch on the ethanol setting in the UP and have good gas, I have NEVER fouled a plug. Keep in mind, mine is an 03 and I have a switch on the dash, not a wire to connect.

All the switch does is moves your timing 2 or 3 degrees and lets it run a little cooler. I usually switch to ethanol the minute I get north of the Mackinaw bridge,,, based simply on the fuel. It doesnt matter the temp. I also run nothing but regular gas as that is what the manual calls for. All the premium does is costs you more $$$. I have compared mileage (while trying to run trails) and there was NO difference at all. I have also ran radar and there was NO difference there at all. Why waste the money?? You stand a much better chance of getting bad gas when you buy premium as it usually is the oldest in the tanks. Most people run regular in their cars and trucks and the gas station go through it the fastest.
This leads me to ask,,,, Why are you spending more on your gas for premium???

When I do run the switch on the ethanol setting in the UP and have good gas, I have NEVER fouled a plug. Keep in mind, mine is an 03 and I have a switch on the dash, not a wire to connect.[/b]
Mine is also an 03, but I took the switch out and made it a plug under the hood. Was always afraid of hitting the switch mid-trail and not realizing it (I wasn't sure what switch would do when I first got the sled). I put my tether switch in the hole where the fuel switch used to be.
Good point on the premium gas, it is more likely to sit there longer... I dunno, I always use premium to avoid any detonation..the way I ride, I'm not the easiest on the sled and would rather be safe then sorry. I do carry around a bottle of isopropyl and use a splash with each fill-up anyways, so any water in the gas should be removed by that. I've never fouled any BR9EYA's either....but have fouled a set of BR9EIX's. :dazed:
My ECU was reflashed to a 04 tune before I bought the sled, so it does run a bit on the rich side....

I wouldnt want to touch the ecu on mine,,, I like my set up from the factory and did give her a little more oil through the oil adjustment screw,,, I do know that the 03 set up was hotter than any of the other set ups,,,, especially if you have an early 03.
I am pretty hard on my sled also and honestly have had NO detonation problems. As far as the heet in the red bottle LOVE IT,,, I always carry a bottle with me and add a little in at every fill up. Great (cheap) protection.

From what I was told by the previous owner my sled is a early production 2003 F-7. The sled blew up somewhere around 2,250 miles on it. From what the previous owner says, the sled grenaded because of the aggresive 2003 tune. It was rebuilt completely by a local Cat dealer and they (the dealer) supposedly sent the ECU to D&D Racing to be remapped. From what I was told, D&D remapped it to a 2004 tune. The motor work was all covered under warrenty also. I bought the sled with 2,300 miles on it and there was still a half tank of pre-mix in it when I picked her up. There is also a small D&D sticker on my ECU...which makes me think it WAS actually sent there to be remapped...not some line of BS I was given.
I've heard many times over that the early production 2003 F-7's were the meanest ones. I would haveta say I believe it too(even after having a 2004 re-tune). My cousin had a all black 2003 F-7 with the Sabercat graphics on it....and I would go right by his sled on top end every time. He did a bunch of work to the machine trying to make it faster and it got him nowhere, results still the same in the end...he even tried new studs for better traction. :rolleyes: A friend of the family also has a 2005 F-7 diamond drive w/studs and I can walk right by him on top end as well..... God I LOVE my RED 2003 F-7. :christmas: The red is what I love the most about it to be honest.... Ya know, RED-FIREcat..they kinda go together..unlike the green snot rocket F-7's... :undercover: LOL Just kidding...I like the green ones too...just prefer my red. :devil: I used to call my cousins green 04 F-6 "The snot rocket", until he sold it. I don't mind the green one's because its staying true to the original Cat colors.....I dont really care for the orange Tony Stewart sleds though.... and I'm even a Tony Stewart fan but still don't care for em.

watch ebay sometime for the firecat ecus,,, you will see some go for 500$ minimum while others fly by at 150$ and a few bids,,, there is a BIG reason for that. DoubleA and I are going to switch ecus some time and run them that way with my ecu on his 06 and his ecu on my 03,,, I will bet the results are different. I am not modified as far as the engine goes,,, I do have mine clutched very well, but I also outweigh him by a solid 75 lb. Same exact track and studs,,, I can take him the majority of the time.
I will bet the results are really different when we swap the ecus,,,

I'm curious to know the results of that. Be sure to post em up when/if ya's ever get around to swapping ECU's. :thumbsup: