A few years ago bought a used 2000 Grizzly 4 wheeler. About 800 miles on it. I do not know anything about engines or fixing them, have tools but no specific mechanic tools.

Was leaking gas from carb, bought a rebuild kit, took it to a guy. I do not know if I bought a rebuild kit and gave it to him, but I think so. PAid him some $, wheeler came back running with no leak.

Used it for hunting season died in woods, took back to guy, some more $, stuff in carb.

Died again this Spring, would not start, I had the service manual and diagnosed it as not having spark, bought stator/ coil, a gasket, some oil, gave it to guy and $200 later I am fixed.

Rode in woods, died (was going slow, fairly hot out.) Able to start next day with lots of throttle, got back to garage. Got it to start in garage a week later, then dies after idling about 3-5 minutes. Pull plug, does not seem to have spark. Checked spark again today (since I had new plug to put in (which did not fit) seems to have spark.

Almost got it to start, with lots of throttle. Tonight, removed carb. Have not disassembled yet. But did find "a lot" of gas on the rubber gasket between carb and engine. (See pic).

What the hell am I doing? I have a carb kit on the way, and have watched some youtube videos. Other than seeing a rip in the diaphram (unlikely?) or some actual plugged jets (I should be able to see that, right), or just crap and dirt, what am I looking for?

I do plan to drain the gas tank in the next day or 2, and check it for dirt and stuff, and maybe put an inline fuel filter in?

I would rather not take it back to the guy (unless I have to), and could take it to the yamaha dealer about 20 minutes away, but I am cheap (which is how I got into a mess with an old four wheeler and a guy). What are the chances of me fixing this myself with arfcom guidance?
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I think the biggest clue is it "almost" catches with lots of throttle, and dies after idling for a bit.
(It also needs a new battery, I have been getting it to turn over with battery and a jump pack.)

Adjust the valves.

Grizzly ATVs are great machines.

Almost certainly in the carb. Lots of possibilities. Float could have a hole in it. Float needle could be leaking. The choke isn’t a true choke…it’s a fuel enrichment needle valve…works by adding extra fuel when engaged.

First thing before you do anything….check the oil. Give it a good sniff. Does it smell like gas? Does it appear watered down?

I can figure that out I guess, and already bought feeler gauges...

I've got an 05 660 Grizzly.

I had carb issues, replaced needle and gaskets.  New battery and it ran great.  The drive trains are stupid reliable, older tech.  This is why I bought it.


Currently, mine is in the barn.  The center dif won't unlock.  20 year old electronics.



Looks like I'm going to be chasing electrical gremlins now.



I'm no expert at all.  With that much fuel in the carb, I'd be looking at the carb again.  Float needle first.  Then I'd look at a valve adjustment (may explain poor operation when running).


On a positive note, once you/we get them sorted out, the damn things should go another 10-20 years.

Those older machines almost never have valve issues. I would get a completely new carb and put it on. I'm betting previous owner ran cheap gas and the lack of use has lead to the carb being gummed up from the ethanol.

Watch several videos on carburetors. Find one that shows the flows through the different circuits.
That looks like a constant velocity carb.

Once you understand the flow circuits and functions it gets easier. Use a clean area and patience.

I cannot stress this enough:
Buy the factory service manual for your machine. An actual manual. You can download one, but for me having it in my hand works better than a download or trying to print out pages.
They seem expensive, but it will save lots of time and money.

Our hunting camp has a variety of quads in the barn, mostly older to very old machines. They all have issues, some more than others. One guy used to have a grizzly, he traded it on a Polaris. Another guy had a different Yamaha, I remember 3 of us taking a few hours to change the carb on that thing.

I have no experience with your model, but most quads seem to have the same issues. In particular, every used quad seems to have a teething period where you need to sort issues to make it reliable.

From a distance and what you posted - clean out the old fuel. Rebuild or replace the carb and be sure the boot between the carb and cylinder is leak free. Only use ethanol free gas and put Stabil in all the gas. When you put it away, close the fuel petcock and let it burn off all the fuel in the carb.

The above process has mostly ended fuel and carb problems for us. Modern gas is garbage, but ethanol free seems to be better.

Checking the valve clearance won't hurt, but I've only seen valves need adjustment on a Kawasaki. If you don't know what you're doing, I'd leave that alone.

Ignition and electronic issues seem to mostly afflict the newer quads. Electronic ignition issues can give you big headaches trying to figure them out.

First of all I’d stop taking it to the guy you’ve been using. Next if it was mine, I’d suck it up and put a new carb after throughly cleaning out the fuel tank and lines. May even replace the lines entirely. With the new carb, start with the mixture screws between 1&1/4-1&1/2 turns open from fully (gently) seated.  That should get you starting, maybe not running smooth, but it should start.

That much gas suggests to me there’s definitely a carb issue. Maybe not the only problem but for sure needs a carb.

While checking the valve clearance is considered to be part of maintenance, it’s actually very rare that they actually need to be adjusted. Definitely not causing your issues in this case.

Some people will recommend an aftermarket carb. That should only be a last resort. Always try to fix the OE carb before trying a Chinese carb. The Chinese carbs are typical Chinese quality….some work great….some don’t work at all. If the inside of the carb appears clean, then usually most issues can be repaired.

Thanks for the collective words of wisdom -
- going to sniff the oil tonight to check for gas;
- going to disassemble the carb tomorrow - thinking of buying an ultrasonic cleaner depending on how it looks. Do not think I know of anyone who has one to use;
- have a service manual - it was pretty helpful with past electrical issues and diagnosing
- will check valves tomorrow against spec
- it spends a lot of time parked, so I should treat it to ethanol free (bet it would easily be less than 10 gallons a year), and let it run the carb out like I do with snowblower and generator and mower at end of season;
- trying to avoid new China carb - have heard lots of bad things - if not needed not touching it;

Will report back on findings!

As far as videos - there are a lot of Grizzly specific ones, including of this vintage, they have been helpful. I also watch A LOT of a channel called 2vintage, where he fixes lots of bikes and quads - his process is boring and the same every time - its actually helpful to see issues tracked down like that!

If you smell gas in the oil then you have a leaking float seat and would also cause your running issues due to excess fuel.

Do you have the plug it was running on? If so, what color is the center electrode?

Will take a pic of plug tomorrow - it was new, maybe has 10 minutes run time, so not sure it shows anything.

Hard to tell if oil smells of gas - the whole quad and garage do since taking the carb off spilled plenty.

<------------  efi Grizzly gang  ('09 550)


Is it possible to upgrade carb to efi?

Need to look at the old plug not the nee one. New one might hold some clues but not likely.

Here’s a link to what you are looking for.

https://www.tuningmatters.com/how-tos/beginners-guides/check-spark-plug-correct-carburetor-setting/?amp=1

How much money you got??  Anything is possible with enough money!!!  But, it’s not really feasible for most equipment.

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Not much of an update: carb is off. I can only get 1 screw off the diaphragm, going to get a manual impact and screw remover tomorrow.

Rest of carb apart as far as I can, nothing seems dirty, gummed up, or plugged.
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