How to Stop My ATV From Running Rich

ATVs need a certain ratio of fuel and air to run well. When there is too much fuel in the mixture, you have what is called, “running rich.” It can be caused by a variety of issues with the fuel or air systems.

This post will be discussing ATVs with carburetors. If you have a fuel injected ATV running rich, you’ll predominantly want to look at the air filter and air box for dirt or blockages, your spark plug, and your ECU.

atv runs lean or rich.jpg

Kill the Choke

You should already be doing this, but we’ll cover it just in case you aren’t because it is the simplest fix.

Turn off the choke when your engine gets warm. If you don’t, you are giving your engine too much gas, and this is why your ATV engine runs rich.

Air Filter

Check your air filter first. It’s a likely culprit, and it’s also an easy fix.

Your air filter may be dirty. If it is, clean or change it.

Intake ducting or a snorkel that is obstructed or kinked can also restrict air flow. Straighten it or remove the obstruction.

Old Gas

Blended gas goes bad in only a month. Pure gas lasts three months. If you haven’t been using fuel stabilizer and or properly storing your gas, it’s probably old and will negatively impact the way your vehicle runs.

Drain the gas and add in fresh. Use fuel stabilizer whenever the gas may be sitting for a month, or every time you fill up. 

ATV waders are waterproof & breathable riding gear
Find out the items that suit your needs

Improper Jetting and Needle Clip Adjustment

If you re-jetted your carburetor and your ATV engine is running too rich, the carburetor may not have been tuned correctly. You’ll need to get back in there and re-jet it again.

Or maybe you didn’t re-jet your carburetor when you should have. It needs to be jetted to accommodate wear and tear, altitude changes, temperature changes, humidity levels, and engine modifications.

All carburetors have a fuel mix screw. Some also have an air control screw. You’ll want to tweak them until you get it to 14.7:1 or very close to it.

The needle clip also needs to be adjusted to account for such things as altitude and modifications. It controls the gas supply in the carburetor, and if it is set too low, you’ll have too much gas flow.

You will either need to remove the needle or remove the entire carburetor to be able to manipulate it. You’ll see 5 grooves in the needle. Adjust the clip so that it is in a higher groove to stop ATV running rich conditions.

Bad Carburetor

The carburetor is more likely to block air flow and cause a lean condition, but it is possible for it to malfunction in ways that cause an ATV to run rich. The jet needle, bowl float, needle valve, or needle valve seat seal could be worn out or damaged and allowing excess gas flow.

Check the parts. They might look visibly worn or you can tinker with the individual parts and see how they impact the gas. Whichever part you determine is faulty will need to be replaced. Thankfully this is an easy and inexpensive repair.

Faulty Choke

We mentioned the choke above. It may be causing a problem all by itself if there is something wrong with it.

Plunger chokes don’t cause rich conditions, so if you have one, move on to another possibility.

Bad Petcock Valve

The diaphragm inside your petcock can malfunction and restrict gas flow or allow too much gas to pass through. If you’re running rich, it is letting too much gas in.

You can look for gas in the vacuum line connected to the petcock or bypass the petcock and obstruct the vacuum line to see if it runs fine without it.

Ignition Issues

Your spark plug may be causing a rich condition if it is:

  • The wrong spark plug
  • Dirty
  • Malfunctioning

A bad coil, coil wire, coil cap, stator, pickup, or CDI can also cause your vehicle to run rich.

Check your spark plug for signs that it is the wrong one or bad. If that doesn’t explain it, use an inline spark test to find the culprit.

Bad CV Carburetor Valves

These valves need to be checked and probably adjusted regularly. This is usually every year or whenever your owner’s manual specifies.

When you’ve got an ATV running rich due to carburetor valves, you can adjust or replace them.

HIT
ENDURO
the most durable
Article
SET
Size
To Be Discussed
Подкатегория товара
Set
687 USD
HIT
ENDURO LIGHT
the most durable
Article
SET
Size
To Be Discussed
Подкатегория товара
Set
478 USD
AQUAMASTER LIGHT
reliability & comfort
Article
SET
Size
To Be Discussed
Подкатегория товара
Set
498 USD
NEODRY
Article
3200
Size
Medium / Large / X-Large / XX-Large
Подкатегория товара
Neoprene socks
15 USD
AQUAMASTER
reliability & comfort
Article
SET
Size
To Be Discussed
Подкатегория товара
Set
687 USD
BELT
Article
8100
Size
-
Подкатегория товара
Accessories
10 USD
ENDURO BF
bootfoot waders
Article
SET
Size
To Be Discussed
Подкатегория товара
Set
558 USD
ALL SEASON
Article
6205
Size
S-M / L-XL / XXL-XXXL
Подкатегория товара
Thermal underwear
71 USD
ENDURO BF
bootfoot waders
Article
5280
Size
10M / 10MK / 10L / 10ML / 10XL / 11LL / 11XL / 12XL / 12XXL / 13XXL / 14XXXL / 11L / 7S / 8S / 8M / 9M / 9L
349 USD
ENDURO
Article
2760
Size
19 / 20 / 21 / 22 / 23 / 24 / 25 / 26
Подкатегория товара
Gloves
17 USD
NEW
TRACE 30L
Article
1711
Size
-
Подкатегория товара
Waterproof backpack
79 USD
TARGET 20L
Article
1716
Size
-
Подкатегория товара
Waterproof backpack
49 USD
-30%
MUDRIDER
Article
5310
Size
Small / Medium / Large / X-Large / XX-Large / XXX-Large
Подкатегория товара
Jacket
259 USD
181.30 USD
NEW
EAGLE
Article
2840
Подкатегория товара
Gloves
19 USD
HIT
MUDWAY NEW
Article
2010
Size
X-Small / Small / Medium / Large / X-Large / XX-Large / XXX-Large
Подкатегория товара
Jacket
209 USD
URBAN
Article
5090
Size
6 / 7 / 8 / 9 / 10 / 11 / 12 / 13 / 14
Подкатегория товара
Wading boots
99 USD
SPORTSMAN
Article
5198
Size
6 / 7 / 8 / 9 / 10 / 11 / 12 / 13 / 14
Подкатегория товара
Wading boots
179 USD
0
Loved it
0
Not bad
0
Not my thing
Go Up
Follow us on social media:
Sign up for more content like this:
Subscribe to our blog
Enter a valid email
I agree to the Privacy Policy.
Share this Article:
Main
Shop
0
Cart
Offers
Categories
Sign up and save 10%
Sign up for exclusive updates and receive 10% off your first order.
I agree to the Privacy Policy
Continue shopping
Your basket is empty