2003 Sportsman 700, Hesitating & Backfiring - Polaris ATV Forum
Polaris Sportsman Discussions for the Polaris Sportsman 90, 300, 355, 400, 450, 500, 550, 600, 700, 800, 850

 
LinkBack Thread Tools Display Modes
post #1 of 9 (permalink) Old 04-29-2019, 04:46 PM Thread Starter
ATV Enthusiast
 
KyleW's Avatar
 
Join Date: Apr 2016
Location: Texas
Posts: 78
2003 Sportsman 700, Hesitating & Backfiring

I recently picked up a 2003 Polaris Sportsman 700 Twin 4x4. It starts and runs decent, but around 40ish mph it starts to hesitate. Also, when slowing down, it sounds like it is backfiring however I hear it at the from of the engine. I have a new set of exhaust gaskets and springs coming this week. What should I check as far as the hesitation? I figure the hesitation and backfire are linked to a carburetor fuel issue. I did replace the spark plugs with two new ones, did not change anything.
Thanks in advance,

Kyle
KyleW is offline  
Sponsored Links
Advertisement
 
post #2 of 9 (permalink) Old 04-30-2019, 09:00 AM
Polaris ATV Legend
 
latebird's Avatar
 
Join Date: May 2014
Location: Illinois
Posts: 4,139
What fuel are you using? Brand, octane, % of ethanol?

I believe you are on the right track - it's a fuel, carb or air filter issue.

Shop Owner and Mechanic with over 50 years experience
latebird is online now  
post #3 of 9 (permalink) Old 04-30-2019, 09:26 AM Thread Starter
ATV Enthusiast
 
KyleW's Avatar
 
Join Date: Apr 2016
Location: Texas
Posts: 78
Quote:
Originally Posted by latebird View Post
What fuel are you using? Brand, octane, % of ethanol?

I believe you are on the right track - it's a fuel, carb or air filter issue.
I am running 87 octane, not sure of the exact brand or % of ethanol. However, I have used fuel from this station(Murphy Express) for all of my machines (including my old 2002 700) and never had issues.

I am wondering if I need to move up a main jet size. Previous owner had fuel screw (or whatever it is called) to 3 turns out. I really don’t want to turn it out more than that. I have no idea what jet size is in there now as I have not been into the carburetor yet
KyleW is offline  
Sponsored Links
Advertisement
 
post #4 of 9 (permalink) Old 04-30-2019, 10:33 AM
Polaris ATV Legend
 
latebird's Avatar
 
Join Date: May 2014
Location: Illinois
Posts: 4,139
Polaris calls for 87 octane (89 if 10% ethanol) - I just run 91 octane non-ethanol in my vehicles

Fuel screw is for idle only - it will not affect running over 1/4 throttle

Some brands of fuel may contain more or less than 10% ethanol - ethanol absorbs water so buying ethanol blended fuels equates to buying a certain amount of water - water will cause ethanol to fall out of the gasoline (phase separation) - in vehicles not used daily the separation is more prevalent - alcohol blended fuels have a shelf life of 100 days in closed containers and about 25 days in open containers (a fuel tank is an open container) - ethanol fuel should be disposed of every three weeks

Shop Owner and Mechanic with over 50 years experience

Last edited by latebird; 04-30-2019 at 10:52 AM. Reason: Added info
latebird is online now  
post #5 of 9 (permalink) Old 04-30-2019, 10:57 AM Thread Starter
ATV Enthusiast
 
KyleW's Avatar
 
Join Date: Apr 2016
Location: Texas
Posts: 78
Quote:
Originally Posted by latebird View Post
Polaris calls for 87 octane (89 if 10% ethanol) - I just run 91 octane non-ethanol in my vehicles

Fuel screw is for idle only - it will not affect running over 1/4 throttle
I’d like to be able to run ethanol free fuel but there isn’t a station anywhere close to me unfortunately.

My point with the fuel mixture screw is generally, turning out makes it richer and in makes it leaner, and on every other machine I have had if it pops on decel it is a lean condition and should be fine tuned by backing that screw out a little at a time. My concern is that it is already 3 turns out, so wouldn’t that be time to go to the next size main? and then retune the screw when the new jet is in place to try to eliminate the popping on decel?
KyleW is offline  
post #6 of 9 (permalink) Old 05-01-2019, 02:05 PM Thread Starter
ATV Enthusiast
 
KyleW's Avatar
 
Join Date: Apr 2016
Location: Texas
Posts: 78
Well, found the problem causing the backfire!
The front exhaust donut seal (or whatever it is called) was completely gone. Replaced all exhaust seals, now way quieter as you can imagine and no more backfiring.

However, it is still hesitating around 45 mph (GPS speed). Is this the normal top speed of Sportsman 700's?
KyleW is offline  
post #7 of 9 (permalink) Old 05-01-2019, 05:21 PM
Moderator
 
polman500's Avatar
 
Join Date: Nov 2009
Location: SE Kentucky
Posts: 8,102
Quote:
Originally Posted by KyleW View Post
Well, found the problem causing the backfire!
The front exhaust donut seal (or whatever it is called) was completely gone. Replaced all exhaust seals, now way quieter as you can imagine and no more backfiring.

However, it is still hesitating around 45 mph (GPS speed). Is this the normal top speed of Sportsman 700's?
Nah, it should run about 60+
Worn belt and tired clutches will cut top speed as will some clutch kits.
You may have carb or other issues if the engine is falling off on top end and limiting speed.
polman500 is offline  
post #8 of 9 (permalink) Old 05-01-2019, 05:48 PM Thread Starter
ATV Enthusiast
 
KyleW's Avatar
 
Join Date: Apr 2016
Location: Texas
Posts: 78
Quote:
Originally Posted by polman500 View Post
Quote:
Originally Posted by KyleW View Post
Well, found the problem causing the backfire!
The front exhaust donut seal (or whatever it is called) was completely gone. Replaced all exhaust seals, now way quieter as you can imagine and no more backfiring.

However, it is still hesitating around 45 mph (GPS speed). Is this the normal top speed of Sportsman 700's?
Nah, it should run about 60+
Worn belt and tired clutches will cut top speed as will some clutch kits.
You may have carb or other issues if the engine is falling off on top end and limiting speed.
That's what I figured.
The more I ride it, the more it reminds me of hitting a rev limiter. Did a little reading and read how sometimes a nut backs off the clutch and causes this same issue, with about the same top speed. Will pull it apart this weekend and take a look, I hope it is that simple.
KyleW is offline  
post #9 of 9 (permalink) Old 05-02-2019, 04:54 PM Thread Starter
ATV Enthusiast
 
KyleW's Avatar
 
Join Date: Apr 2016
Location: Texas
Posts: 78
Solved! The nut had backed off the clutch. Snugged it back up and it is hitting 55ish before I run out of road and still climbing.
KyleW is offline  
Reply

  Lower Navigation
Go Back   Polaris ATV Forum > Polaris Model Specific Discussions > Polaris Sportsman

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Polaris ATV 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
2000 Trail Boss Brake Lines Bigsmooth1081 Polaris Trail Boss 2 02-04-2019 08:49 AM
Will this oil filter work (#2540086) - '14 Sportsman 850 Skippy850 Polaris XP 7 01-17-2019 07:56 AM
VIN - Sportsman 500 or 500 HO? das86turbo ATV Repair and Maintenance 7 01-02-2019 06:58 AM
Clutch Trevor Goodrum ATV Performance Modifications 4 09-13-2018 01:43 PM
Wheel bearing brands DAKOTAKIDD Polaris Sportsman 19 03-17-2017 09:51 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