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2008 Grizzly 700
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Discussion Starter · #1 ·
Well first post here as I have had the Grizzly home for only a week. Long story short, a friend bought it used about3 yers ago now to plow his driveway. Used it th first year but the summer the stator and rectifier went out of it. I replaced them for him and it ran again with no problems. Soon after though he ended up needing a new starter and got one put in by the local dealership. Again things were fine but he left the machine outside till winter, then it would not start and it had sat in that same spot until last week. He sold his house and not being mechanically inclined he was not wanting to put any money into the quad that he would no longer be needing so he told me that I could have it. Ended up haggling that I would take him and his wife out for dinner for it at the very least.

I got it home, opened the gas tank and could smell that the gas had gone bad. He said he didn't put any stabilizer in it and that was the truth. I siphoned the gas out of it and found that there was plenty of water in the tank as well. I threw a little seafood and methyl hydrate in the tank with the last little bit and put some new marked fuel into the tank. It sputtered and stalled lots so I pulled the plug and found the it was nicely fouled. Turning the machine over the spark was quite lazy and yellow, not the crisp blue like on my Kodiak. I hit the local dealership and low and behold, the pice of the plug was amazingly cheap (first time I have ever seen that at Yamaha). I dropped a new plug in it and fired it up. She ran rough to start and the methyl hydrate definitely caused the exhaust to glow a little but then it was soon burnt out and it was idling nicely for a good 10 minutes.

With that success I turned it off and put a battery maintainer on it because the temps hav been pretty cold and it would be until today that I could get back to it. Well today I went to fire it up and it was stalling and backfiring like crazy. Even every once and a while it would make a strange noise when it stalled like a whirring noise hat was slowly winding down after the motor quit. I pulled the plug out and found it carbon fouled, so I cleaned it up a bit and put it back in. I fired it up again and it acted the same way. I only ran it for about 30 seconds then shut it down. I pulled the plug and again it was super carbon fouled.

So this is my first EFI machine (currently have a 1995 Kodiak, 1995 Big bear, and 2005 Kodiak, all carb machines) and I am not sure why it would be running so rich. I went through the diagnostic screen and all the values seem to be right on. Can someone offer some advice on where to look next? I was thinking of the injector, but not sure if that would cause the rich condition unless it was stuck open or something from the varnish. Thanks.
 

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2008 Grizzly 700
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Discussion Starter · #3 ·
Thanks Patroller. I'm heading out of country for a couple of weeks here and figure I can get back to cleaning the fuel system then. I just dumped some fuel injector cleaner and seafoam in the tank to sit while I'm away. I'll pick up a few plugs while I'm at it. I am guessing that it's going to take a bit to get things cleared up, but hey free is always good.
 

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2014 Yamaha Grizzly 700 EPS
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4,399 Posts
You mentioned going through the diagnostics, I forget what was available in the diag screen, but did that include making adjustments to fueling via what is referred to on GC as the POD Mod? I would agree to fully clean the fueling system but if you haven't, look up POD Mod for the 07/08 Grizzly 700. The previous/previous owner may have messed with that.
 

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Welcome from Colorado.
Injector cleaner is corrosive on rubber lines.
As it starts, there's not much wrong. I suggest a long ride to get the engine hot and keep it hot.
 
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................................ I threw a little seafood and methyl hydrate in the tank with the last little bit and put some new marked fuel into the tank. It sputtered and stalled lots so I pulled the plug and found the it was nicely fouled. ............................
I never could get my Grizzlies or Kodi's to run on Seafood. They seem to like Dino more.


While water was an issue n0w the issues seem to point to the valves badly in need of adjustment. Hard or no starting when cold weather rolls in with bad plug fouling is a real indication that the valves are very tight.
These machine seem are susceptible to valve seats that wear in from the constant pounding they take. That is why they almost always are very tight when inspected. If you flood the engine then right away put in a new spark plug they will almost always start.
 

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Welcome from Colorado.
Injector cleaner is corrosive on rubber lines.
As it starts, there's not much wrong. I suggest a long ride to get the engine hot and keep it hot.
A long ride seems to be the answer to a great many things both mechanical and not. :)
 
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