Yes the burn down is on the exhaust side.
There aren't very many miles on this sled, so I am wondering why it has had two burn downs now in 600 miles.
Anyway, the mains are 150 and the pilots Im not sure but they are stamped H160.
I just put the carbs back together and decided to put the needles at 3.5. I thought it might be too much of a jump to go from 3.0 to 4.0. Thoughts?
There aren't very many miles on this sled, so I am wondering why it has had two burn downs now in 600 miles.
Anyway, the mains are 150 and the pilots Im not sure but they are stamped H160.
I just put the carbs back together and decided to put the needles at 3.5. I thought it might be too much of a jump to go from 3.0 to 4.0. Thoughts?
super1c
Super Moderator
Moving the needles to 4th groove both on top takes you to 3.25 which is what mr viper recommends. Where did you put the clip and shims? Here is a good link on clip position. Want to make sure were all on same page because those needles can be confusing. Going all the way to 4 would be a huge jump. He said even 3.5 might burble a bit in the mid range. http://www.totallyamaha.net/forums/showthread.php?t=84296
Yeah, I reviewed that post before moving mine. And yes these darn needles and settings are confusing.
They were set at clip in the third groove (middle groove either way) and two washers under or towards the pointy end. I understand this to be a 3.0 setting, correct?
I now have the clip in the fourth groove from the pointy end with the two washers under the clip or towards the pointy end. I understnad this to the the 4.0 setting, correct?
Thanks for the help guys.
I definitely want to make sure I put this thing together correctly this time. I thought she was solid and going good, but then everything came to an abrupt stop!!! not good.
They were set at clip in the third groove (middle groove either way) and two washers under or towards the pointy end. I understand this to be a 3.0 setting, correct?
I now have the clip in the fourth groove from the pointy end with the two washers under the clip or towards the pointy end. I understnad this to the the 4.0 setting, correct?
Thanks for the help guys.
I definitely want to make sure I put this thing together correctly this time. I thought she was solid and going good, but then everything came to an abrupt stop!!! not good.
Sailopus
I think you may have the wrong position. Your clip should be in the fourth grove down from the blunt end with two washers below that clip to achieve the #4 position. I may have misunderstood you but the higher the number the more your lifting the the pointy end by lowering the clip.
I would also pull your pilot jets out again. Borrow or get a magnifying glass and look real close. Because that number doesn't ring a bell for me. If in question, I would chunk them and get some new ones so you know what you're dealing with. I think it's real important to know what they are since they are part of the mid range equation along with those needle settings. And the mid range is where most vipers develop burn downs.
JMO
I think you may have the wrong position. Your clip should be in the fourth grove down from the blunt end with two washers below that clip to achieve the #4 position. I may have misunderstood you but the higher the number the more your lifting the the pointy end by lowering the clip.
I would also pull your pilot jets out again. Borrow or get a magnifying glass and look real close. Because that number doesn't ring a bell for me. If in question, I would chunk them and get some new ones so you know what you're dealing with. I think it's real important to know what they are since they are part of the mid range equation along with those needle settings. And the mid range is where most vipers develop burn downs.
JMO
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If the clip is in the 4th groove from the pointy end (bottom of the needle), then the carbs are leaned out compared to the clip in the 3rd groove from the pointy end. Since both washers were under the clip at each setting (3rd groove and 4th groove), the carbs were leaned out by one full clip position with the clip change.
Here's another way to look at it, moving a clip higher on the needle (towards the blunt end) actually lowers the needle into the jet, thus restricting gasoline flow, in other words, leaned out.
Here's another way to look at it, moving a clip higher on the needle (towards the blunt end) actually lowers the needle into the jet, thus restricting gasoline flow, in other words, leaned out.
ok I guess I had it backwards and need to take them apart again. Good thing I have you gusy to keep me straight!!! 
What altitude and temps are you riding in? I wanted to bounce your settings off the jetting chart to see if you're in the ballpark.
super1c
Super Moderator
Here is the groove chart. http://www.totallyamaha.com/snowmobiles/aaTECH/CarbNeedles/CarbNeedles.htm
I ride at around 6000 - 7500 elevation, and typically 20-40F temps.
Using the chart:
MJ=Main jet
PJ=Pilot jet
JN=Needle clip position
PS=Fuel screw turns out from all the way seated
MJ: 147.5
PJ: #50
JN: 2.5
PS: 2 5/8
I run in similar elevations and slightly lower temps and I run:
MJ: 143.8
PJ: #52.5
JN: 3.0
PS: 2.0
This has worked well for me but if you want to sit on the conservative side maybe this would work ok for you:
MJ: 147.5
PJ: #50
JN: 3.5
PS: 2.0
This is all personal choice so I'm just trying to give you some numbers you should be near not necessarily anything specific.
MJ=Main jet
PJ=Pilot jet
JN=Needle clip position
PS=Fuel screw turns out from all the way seated
MJ: 147.5
PJ: #50
JN: 2.5
PS: 2 5/8
I run in similar elevations and slightly lower temps and I run:
MJ: 143.8
PJ: #52.5
JN: 3.0
PS: 2.0
This has worked well for me but if you want to sit on the conservative side maybe this would work ok for you:
MJ: 147.5
PJ: #50
JN: 3.5
PS: 2.0
This is all personal choice so I'm just trying to give you some numbers you should be near not necessarily anything specific.
Tnks for the settings Old Iron.
Finally had a chance to tear into the carbs today a bit. Here is what it was set at when I had the lean burn down (at least that is what I beliee happened):
Main jet - 150
pilot jet - 51
JN - 2.5
PS - 1 5/8
After reading a bit, and your recommendations I think I will set it up with:
Main jet - 147.5
pilot jet - 50
JN - 3.0
PS - 2.0
The chart actually says to go to 2 5/8 turns on the screw. Iwill also use octane booster (amsoil) from now on.
Anything else or any other opinions?
Finally had a chance to tear into the carbs today a bit. Here is what it was set at when I had the lean burn down (at least that is what I beliee happened):
Main jet - 150
pilot jet - 51
JN - 2.5
PS - 1 5/8
After reading a bit, and your recommendations I think I will set it up with:
Main jet - 147.5
pilot jet - 50
JN - 3.0
PS - 2.0
The chart actually says to go to 2 5/8 turns on the screw. Iwill also use octane booster (amsoil) from now on.
Anything else or any other opinions?
bluemonster1
LIFE MEMBER ONLY ONCE!!!
octane boosters really don't raise your octane like you think.I have been using Fitch Fuel Catalyst in my tanks.. works great and never have had issues with my fuel.It keeps fuel fresh and ups the octane.I use it in my truck also and all my small engine equipment..
http://www.fitchcatalyst.com/
you would use the F5T in a 10 gallon tank
http://www.fitchcatalyst.com/
you would use the F5T in a 10 gallon tank
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srxguy
Member
Your going to lean out the main jet? Just curious why...oh cause of elevation?? I think I got it nowSailopus said:
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Sailopus said:
Sailopus
I think those settings will work well for you. Just make sure you do some plug checks once you get her back on the snow. As you mentioned above the chart calls form 2 5/8 out on the pilot screws. A lot of members here want to keep that under 2 so that the springs pushing down on the needle have enough tension to keep them where you want them. I ran mine at 2 and when I pulled the carbs out for their annual cleaning I noticed they were at 3. So I ordered some new springs and I'll put them in next year.
The 2 revs out on my fuel screw is leaner then what the book is calling for so my pilot is slightly richer. Taking care of the the low end circuit. On my midrange circuit (pilot and needle) I may be slightly rich but it's a little insurance if the temp drops. And my high circuit (needles and mains) seems to be good according to the plug checks. With that said my mid is also good with plug checks.
Just make sure you verify those settings with plug checks and you'll be good to go. When you hit the kill switch, keep the throttle where it was untill all movment has stopped. You want to keep the engine lubricated as it costs down.
