Arctic Chat : Arctic Cat Forum banner

1 - 4 of 4 Posts

1 Posts
Discussion Starter #1 (Edited)
So, I'm here with an issue or three. I Bought this 2003 mountain cat 900 with ATACC in November with low mileage on a rebuilt engine and 1800 miles total. It rode fine initially for a test ride when got it back to Fairbanks. Since then,
General issues
>Hard, Hard starting (hydrolock?)
>Fuel leak
>Clean carbs and take a look at float and needle assembly. Think we are good.
>Discover Fuel hose in tank has disconnected and its not supplying fuel. Fix that.
>Fuel leak filling crankcase. Back to square one
>Replaced floats and needles, drained crankcase and running
> Sled ran good a couple trips down the road half throttle
> Died revving throttle to full under no load. Like stopped dead
> Would not pull Start initially, even with the plugs out,
> Rotating the primary by hand something loosened up.
> Able to get it started again, seemed to idle smoothly for a few seconds. Killed til I can get more info.
>> Compression on the Left is 105psi, and on the right is 122psi or so. Not sure what the specs. or tolerances are. Have seen compression online up to 165psi. Help!!!

Full description

Took it out riding, was a huge pain to start, and began bogging on trail immediately. Let it thaw in the garage and ran it, seemed fine under no load reving.
The next day without riding it, it began leaking fuel into the garage. We discovered it was filling up the crankcase.

Went and rebuilt the fuel pump. Didn't work,
Pulled the carbs apart and check the float/needle set up, cleaned it, that seemed to help stop the fuel leak, until we now could not get fuel flowing to the engine.

Discovered the fuel hose in the tank had just broken off and fuel was below the supply port. Fixed that.

Able to start and run the sled. Think we got this fixed and drive three hours to ride only to get out and find on pulling, that the sled wont start and we see gas leaking out the exhaust. Plugs out we are able to spray fuel out of the cylinders.

Take home, thaw out, Replace floats and needles completely. Cannot find a drain plug for the crank case, so we pull plugs and begin pulling her over. 2 pulls in we are shooting gas to an 8 ft ceiling. I've seen supersoakers do less. The spray works regress to a light spray shortly.
we decide to give a shot once the cylinders are somewhat dry.
After a bit of pulling we get it running and let it idle for a bit to burn out whatever fuel we missed in the crank case.

Test Drive: I rip a couple times down the street half throttle all is good.
Can't control her on the ice at full throttle, so we pick up the back and and run her up full a couple times. The second time, three seconds into 7/8 throttle she stop dead, no spin down. Not a happy time.
Cannot pull it over, pull the plugs and still can't pull it.
work the primary loose by hand, now it will pull.

Plugs did not show lean burning.

Cylinders Left shows 105psi and right shows 122 or so.
I pull her over with the plugs in and she starts up quick. I kill it until I can get more info. And here I am now

Headed home tonight to see if at least the fuel leakage has stopped.
But is compression in spec? Anyone else have these issues. I hear these are beast of a sled when running. Right now its just keeping my garage from going anywhere. Help!!

10 Posts
have you checked that all the carb pieces were in spec for your altitude and temp? i.e. main jets, pilot jet, needles, air screw, fuel screw, clip location?

721 Posts
Sounds like you stuck the motor. Pull the cylinders off and see what you have for damage. If you can't pull it over and have to move the clutch to free it up it has been seized. You might see something if you pull the Y pipe off and look inside. Compression is not in spec, there should not be that much difference between them

1,528 Posts
After you rebuild the top end you will need to pull the carbs and put new float and needle kits in, clean everything and Jet for your elevation. The ATACC can fail for a number of reasons. If you get fuel in the lines it will screw them up. Sucks but you are not the first guy to go through this. You also need to unplug the little blue line and plug it back in again, that adjust internal pressures to your present elevation. Check out their web site for installation and check how yours is installed. Seen a few guys screw them up pretty good.
1 - 4 of 4 Posts