Arctic Cat magnetic carb switches

Arctic Cat magnetic carb switches

Post by JWentwort » Wed, 31 Dec 2008 21:58:33

First time I've seen this problem so thought I'd pass it along.

A friend bought a new Arctic Cat Z-570 2-3 years ago and had a problem with
the engine stalling at idle when the engine was warm. After a cold start it
would idle at 1700 rpm without any problem.  He took it back to the dealer a
couple times but the problem persisted.

Because you could make the engine run by simply moving the throttle lever
enough to actuate the throttle switch it was clear that the stalling was
caused by the ignition. The cause was the adjustment of the magnetic switch
on one carb, but I don't know why engine temperature changed the symtoms. At
a cold idle the switch was open, at warm idle the switch was closed.
Combine a closed magnetic switch and the throttle at idle position (throttle
switch closed), and the ignition gets shut off.

Using a multimeter or DVM it's an easy problem to diagnose once you get past
the pondering about why engine temperature makes any difference. The biggest
PITA is re-installing the baffle hardware after the adjustment is done.

Another thing to ponder is why two trips to the dealer weren't sufficient to
fix this problem.

I also noticed that the manual calls for a 1500 rpm idle, but, when warm,
the motor wants to idle at 1000 or 2000 rpm. When cold it spins at 1700 then
drops to 1000 as it warms up. We were trying to set the idle with the airbox
(baffle) removed and maybe that caused the inability to find an idle
somewhere in the middle between 1000-2000 rpm.