QuestionI have a 1980 Arctic cat Jag 2000. It has a 275cc engine. It was running fine. I went to start it about a couple of weeks later and it had a severe miss on both cylinders. It starts great but won't rev enough to engage the clutch. When I give it throttle it bogs and blows fuel back out the carb.
So far I have replaced the cdi, coil, Stripped down the engine and checked the rings,pistons,rod,crank, crank seals, and replaced all the gaskets when I put it back together. I have taken apart the carb several times and cleaned,cleaned, cleaned. I have bypassed the fuel pump (using gravity feed). I have removed the magneto and did a simple ohm meter check. I have played with the timming.
All have fixed nothing. Its getting good blue spark. The plugs are sooty so its running rich. Adjusting the pilot screw and the main needle have no effect.
Any suggestions would be apperciated
Dave
AnswerAdjusting the pilot screw and the main needle have no effect. If you are telling me that these adjustments make no difference in how the engine runs, the carb is still plugged. However, if the plugs being sooty indicates a rich condition (which is not typical of a blockage in the carb) or an ignition problem.
Carb: I would suggest making sure the float floats and pivots smoothly. Then make sure the inlet needle and seat are in good condition and the float level is correct (level with carb body when carb is turned upside down).
Ignition: If you suspect it is ignition, connect an inductive timing light to either of the spark plug leads (same as you would do on a car) and observe the light when the engine runs poorly. If there is a missing condition, you will see it show up in the light. If this is the case, you will need to inspect the ignition system thoroughly (especially for cracks in the coil pack).
Hope this helps.
