01 AC ZR600 carb backfire - ArcticChat.com - Arctic Cat Forum
 
LinkBack Thread Tools Display Modes
post #1 of 8 Old 04-13-2019, 03:09 PM Thread Starter
Junior Member
 
Junior Member
Join Date: Apr 2019
Posts: 7
Thanks: 0
Thanked 0 Times in 0 Posts
01 AC ZR600 carb backfire

Chasing a backfire on the sled. I’ve replaced: plugs (eya) plug caps, reeds (Boyesen), reed cage gaskets, in-tank screener and fuel line, tank to fuel pump fuel line, fuel pump to carb line, fuel filter.

I’ve cleaned the carbs 4xs, looks like one float was recently replaced, other original.
Adjusted fuel mixture screw 1.5 turns out.
Drained tank and filled over half tank with new fuel.
I’ve checked exhaust pipe and can for obstruction, no tears in carb boots or intake rubber.
I DID clean a nest out of the silencer box. Cleaned that as well as the tray the silencer box sits on top of.
Tested conduincy of stator and ground. Scrubbed and sprayed grounds with elec cleaner.
Compression test (110 both).
Prob done more but have done a lot. Sled starts on one pull and idles but it backfires (poofs) at carb exit (I can see smoke come from the manifold to exhaust pipe connection).

Stator ohms-out fine but still may be issue. Maybe it’s crank seals? Maybe it’s key way stuff?
The only thing I can think of is replacing the old float or tuning the problem out with mixture screw? Throw a coil pack at it?

Any ideas appreciated, thanks
Socomoddjob is offline  
Sponsored Links
Advertisement
 
post #2 of 8 Old 04-13-2019, 03:25 PM Thread Starter
Junior Member
 
Junior Member
Join Date: Apr 2019
Posts: 7
Thanks: 0
Thanked 0 Times in 0 Posts
Oh, 3200 miles on sled...
Socomoddjob is offline  
post #3 of 8 Old 04-20-2019, 12:06 AM Thread Starter
Junior Member
 
Junior Member
Join Date: Apr 2019
Posts: 7
Thanks: 0
Thanked 0 Times in 0 Posts
Further searching and I found the tm38 flat side carbs have air screws. I pulled the carbs and cleaned again, had some gunk come out of the air screw passages. Reassembled, set the fuel mixture screws to 2 turns out and the air screws at 1.5 turns out. Are these settings correct? I searched the forum and got 4 different settings for air screw. 1.5, 1.75, 1.25 and 2 turns out.

It’s still backfiring. It’s smokes too but it’s 60F today. Idles and doesn’t die but intermittent poofs. Idle slows and backfiring stops when I half choke. Disconnecting TSS makes no diff either way. The exhaust pipe moves a bit on throttle blip, exhaust escapes the gasket at the y-pipe/exhaust connection. I ordered a new gasket and new springs for fun.

Anyone? Thanks in advance
Socomoddjob is offline  
Sponsored Links
Advertisement
 
post #4 of 8 Old 04-22-2019, 10:40 PM Thread Starter
Junior Member
 
Junior Member
Join Date: Apr 2019
Posts: 7
Thanks: 0
Thanked 0 Times in 0 Posts
I tested the ignition sensor (brown and green wires), came back 184.4 so I think thatís in +- range of 190ohms. Blaine video for the stator is a conduit test only and that ohms out fine including ground.

Found another settings for air and fuel screws. I went from 2 to 1.5 turns out on the fuel. Still backfires (half choke runs better but then dies).

Had to buy a long 1/8 straight slot to get to the air screw, going to set those from 1.5 turns out to 2. Saw a post saying 2.5 times out to compensate for tm carb issues? Iím addressing lean issue as thatís related to backfiring. Found a thread where more air equals more fuel.

I was able to bring a 98 zl500 back from the dead after 3 years sitting last month. None of the tricks are working for this

This thing on?
Socomoddjob is offline  
post #5 of 8 Old 04-23-2019, 10:33 AM
Junior Member
 
Junior Member
Join Date: Apr 2019
Posts: 22
Thanks: 0
Thanked 1 Time in 1 Post
I am on the ATV sides of Arctic Cats. A quick google search indicates a carb backfire is because it is lean. Did you let it warm up before revving it? They can run lean until warm. Maybe try upping the pilot jet, or rechecking it. Mine would idle fine but loose power in the higher rpm and speeds. I went from stock #38 to a #40 and it runs much better.

Last edited by GWgameing; 04-23-2019 at 10:38 AM.
GWgameing is offline  
post #6 of 8 Old 04-23-2019, 02:49 PM Thread Starter
Junior Member
 
Junior Member
Join Date: Apr 2019
Posts: 7
Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by GWgameing View Post
I am on the ATV sides of Arctic Cats. A quick google search indicates a carb backfire is because it is lean. Did you let it warm up before revving it? They can run lean until warm. Maybe try upping the pilot jet, or rechecking it. Mine would idle fine but loose power in the higher rpm and speeds. I went from stock #38 to a #40 and it runs much better.
Thanks for your response! Yep, I mention the lean in post above yours.

I let it run for less than 5 minutes but longer than 2. Iím going to order a manual as I canít find the definitive air/fuel settings. Iím also considering moving the needle up/down?

Iíd really like to find stock settings for those things and then move to replacing jets and such. I assume Iíd have to change carb settings with new jets and I donít know what to set those to!
Socomoddjob is offline  
post #7 of 8 Old 04-23-2019, 06:25 PM Thread Starter
Junior Member
 
Junior Member
Join Date: Apr 2019
Posts: 7
Thanks: 0
Thanked 0 Times in 0 Posts
Manual doesnít list screw specs. The e-clip on the needle is at middle position. I may drop it down one notch to see if that fixes the backfire. Iíll be running fuel at 1.5 out and air at 2 out.
Socomoddjob is offline  
post #8 of 8 Old 04-23-2019, 09:42 PM Thread Starter
Junior Member
 
Junior Member
Join Date: Apr 2019
Posts: 7
Thanks: 0
Thanked 0 Times in 0 Posts
Better! Screws set as above. Left the clip at middle. First 20 seconds no backfire. Next 40 seconds it backfires a few times. Gave it a blip of throttle and let it run for 2+ minutes. No backfiring at iidle or blip. Canít ride it to test but better than when it arrived.

So would you:
A) Go 1/2 more turn out on air In order to increase fuel flow?
B) drop needle one notch?
C) leave it. Give it back to your bro in law.
D)none of the above
Socomoddjob is offline  
Reply

  Lower Navigation
Go Back   ArcticChat.com - Arctic Cat Forum > Snowmobiles > Arctic Cat Snowmobiles

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the ArcticChat.com - Arctic Cat Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Similar Threads
Thread Thread Starter Forum Replies Last Post
05 500 - carb hoses and choke harness location Seth Katolas Utility ATV repair and maintenance & Troubleshooting 0 03-07-2019 01:50 AM
99 ZR 700 Pipes on 02 ZR600 carb? Matt Loomis Z/ZL/ZR/ZRT/Tcat/EXT/jag/cougar 3 02-14-2019 09:30 AM
97 ArticCat Bearcat 454 4x4/AWD Carb Issues Texas19829 Utility ATV repair and maintenance & Troubleshooting 0 05-10-2018 06:16 PM
2002 zr600 carb motor swap to zr800 oliphant Z/ZL/ZR/ZRT/Tcat/EXT/jag/cougar 5 01-18-2016 09:11 AM
2002 zr600 carb no spark please help! oliphant Z/ZL/ZR/ZRT/Tcat/EXT/jag/cougar 8 12-14-2015 09:21 AM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome