xcsp 440 low end bog

[broken_line]

i have a xc sp that untill about 25 mph it feels boggy but after that it takes off! i cleaned the carbs and exhaust valves along with a new belt. could it be the needles? it gets worse with warmer temps.. thanks!

[barebackjack]

I had the same thing on my XC700, ended up that one of the plug gaps was off.

[toughguy]

Make sure you have the proper jetting in your carbs too. It's a good idea to replace them every so many years if you didn't do it when cleaning your carbs.

[leech~~]

When did you run it last? If you just tried it after sitting over the summer? Check the Air box and exhaust for mouse nest blockage!

[broken_line]

i havent checked the gap.. also before i took off i noticed a large nest in the air box but never checked in the exhaust. also when its coldish and you punch it, it cuts out if you dont let off the throttle again. think its running lean or the bad gas gummed the carbs after i cleaned them?

[Surface Tension]

New plugs of coarse would be the first thing to do.

Next pull the air box off.

Drain the bowls on both carb.

Check the carb boots for cracks.

This is a good time to check the fuel lines and their connections.

Check the impulse line from crank to fuel pump.

Anyone that works on small engines should have a primer bulb with fuel lines attached to it.

That will be your siphon hose and aux fuel line.

You can substitute a gas tank and lines from an outboard till you get the above.

We're checking the fuel delivery and condition here.

Remove the inlet fuel line from the fuel pump.

Attach the outlet line on your primer/siphon line.

Put the inlet pickup end of the hose into a gas can with fresh gas.

With carb bowl plugs out, pump gas via primer bulb to flush out bowls and fuel line.

Install the bowl plugs and prime the carb with bulb.

Start the engine.

If your bog disappears you know the fuel in the sled is bad.

Let it run to be sure the fuel pump continues to work.

If you still have the bog you eliminated the source and it isn't the fuel or pump.

Since you have the air box off I'd clean the carbs to be sure they aren't your problem.

Leave the aux fuel system in place and test with clean carbs.

If you still have the bog a compression test should be done but a hunch would be bad seal on the PTO side.

You can try spraying starting fuild there with engine running.

If the engine picks up then your seal is bad. If it doesn't, that isn't a guarantee the seal is good though.

[broken_line]

compression in each cylinder is 123 thanks! i will have to look into the pump and see if the filter is clogged with crud. i removed the clutch and ran it it idle sprayed the seal, ran it at 4k and sprayed it all it did was clean the shaft off didnt speed up or slow down or change sound. would polaris gold springs along with 10mb weights bring my engagement back to around 6000rpm?