Rotax 582 Greyhead Problem

[lv2plyguitar 172]

I had previously posted on this forum an issue with my engine inadvertently reving up 600 rpms without giving it throttle.  Last night I found a strange problem that I do not know how to deal with.

 

The same problem started again.  The engine reved from idle 2000 rpm to 2600 rpm.  After a minute it reved from 2600 rpm to 3200.  I pulled the cowling and found the strangest thing going on.  The carb piston is raising on its own and causing the cable housing on top of the carb to set on top of the brass seat therefore not letting the carb piston to go back down.  When one carb does it the rpm goes up 600 rpm.  When both do it the rpm goes up to 3200.   

 

Both carb boots are tight and brand new.  The egts run normal as well as the engine temp.  It seems to run rough at idle.  I am wondering if the jerking action of the engine would create enough force to cause the carb piston to raise up and down on its own.

 

Help

[Russ. 7]

When you say carb. boots are you referring to the carb. to eng. boot or the throttle cable boot to the top of the carb?  I had problem with the throttle boots and safety wired them.

[lv2plyguitar 172]

The part I am talking about is the brass cup on top of the carb that the throttle cable rest in.  The throttle cable, even with all slack taken out comes out of the top and rests on the lip of the brass cup.

[akflyer 1427]

The only way that can happen is if the inflight mixture cables are dragging and not letting the pistons in the carb come back down freely.  You already safety wired the cables to the top of the carbs now, but I would really check those infight cables and make sure they are moving freely inside the housing!  It does not take much of a "pinch" in those cables to mess up the whole works. 

 

[akflyer 1427]

Second thought.... is there any signs of galling in the carb barrel??  the way you were desbribing it on the phone, it seems that there is still tension on the carb barrel when you pull the throttle back to idle.. that can really only come from the infight mixture cable...