Polaris IQ Fuel, Spark Troubleshooting

 

FUEL DELIVERY
First off start with a full tank of fresh gas. You cannot Prime the fuel system on these sleds with only a half of a tank because of the angle of the tank. Also the line inside needs to be coiled up like a snake laying flat on the bottom. If the line is pointing up towards the top or has gone stiff it will only suck air. You may need to index or turn the fuel line on the adapter that sticks out of the tank to a position that allows it to lay flat. We have a video on this on YouTube talking about fuel tanks. Next use a coat hanger to fish out the fuel pickup and make sure the line is okay and that the filter has not rubbed through. If either of those are bad you have to clean your entire fuel system and that includes the pump, the lines and the T in between the the carburetors which you must remove the float assemblies/needle and seats and then blow air through. The next thing that commonly fails on all Mikuni carbs is the needle and seat o-ring. We offer a larger than stock one that works better and lasts longer. Put on some safety glasses and use some carb spray and make sure every single transition port in the carburetors are clear and flowing as they should including the pilot air jet that goes in the back of the carburetor next to the airbox. Next make sure you have slack in your choke cable, can put a penny under the lever and that the plungers are going all the way down at the carbs. It's a good idea to lube all of the linkage at this time too. Make sure there is a little play in the throttle cable as well once everything is mounted backup. This should solve any fuel delivery problems except for the fact that now everything is dry and will require several pulls of the rope, possibly 20 to 30 to reprime the system. There are other ways to do this if you feel comfortable with it like putting a very small amount of fuel down each spark plug hole then reinstall the plugs and pull the rope with your right hand holding on to the break with your left hand. You can also do the same trick by spraying carburetor cleaner down the air intake but once again make sure you are holding the brake when you pull the rope. On our website under the tech notes section there is a section about cautions and troubleshooting and at the very bottom of that page there is an entire write-up on how to tune the low end on your carburetors.
SPARK
To check spark simply unplug the two spark plug cables off of the spark plugs. Put two new spark plugs in the caps and lay them on the head. Shut the lights off in the garage if you can and pull the rope and see if both plugs are sparking. They both should be sparking at the same time. If only one plug is sparking then you have a bad ignition coil. If they both are sparking then pull your old ones out and replace them. If you have little to no spark there is a possibility that something is grounding out. If that is the case start by unplugging everything on the handlebars and checking both tail light and headlights. Anything that grounds out in the system will kill your spark. Next thing we do is hit the kill switch then pull the plugs and do a compression check with a compression tester. Just pull the rope 3 times per cylinder. You do not have to hold the throttle open and doing so will only give you a false slightly higher reading. You should have 120 PSI or more per cylinder and it shouldn't be off by more than 10psi between the 2 cylinders or you're due for a rebuild. After that with the spark plugs still out we run one cylinder to the top dead center position then use a wooden dowel to press down on the opposite piston. If the Piston moves or you see the clutch move that means your crank is twisted and will need rebuilt.
Critters
Sometimes criters like to get into sleds and build a nest or store nuts in the intake, airbox, plenum, exhaust or even cylinders. sometimes they chew right through wires and hoses so check over things.