Posts
114
Joined
6/15/2016
Location
Cleveland, OH
US
mx724
4/23/2021 1:14pm
4/23/2021 1:14pm
Edited Date/Time
4/24/2021 9:10am
Pretty common problem. I have disassembled the carb and cleaned every passage twice with compressed air, let the jets soak over night and still just seems like there is an air leak somewhere or maybe its time for some new jets?
I noticed in the OEM carb it appears to have 2 pilots (See parts 2 & 3 in the diagram) I poked around on some JR 50 forums, some people remove one of these 2. Im not looking to do that, but the owner bought a ebay carb and it appears that the ebay carb only has one jet in this location. He was trying to make it run with the ebay carb.
I went back to OEM which initially it wouldn't even run with, after a cleaning its running, albeit erratic.
Ebay carb jets have no markings at all. Took a quick look on the left side crank, dont see any oil, not to say that the crank seal couldn't be leaking? Maybe someone with JR experience can point me to known problem areas before I go chasing all over.
I will also mention that the air screw is 1 1/4 out and the idle set maybe 3 turns in. Ive fiddled with both while running at at times just seems to cause the idle to run off, regardless of turning in or out.
I noticed in the OEM carb it appears to have 2 pilots (See parts 2 & 3 in the diagram) I poked around on some JR 50 forums, some people remove one of these 2. Im not looking to do that, but the owner bought a ebay carb and it appears that the ebay carb only has one jet in this location. He was trying to make it run with the ebay carb.
I went back to OEM which initially it wouldn't even run with, after a cleaning its running, albeit erratic.
Ebay carb jets have no markings at all. Took a quick look on the left side crank, dont see any oil, not to say that the crank seal couldn't be leaking? Maybe someone with JR experience can point me to known problem areas before I go chasing all over.
I will also mention that the air screw is 1 1/4 out and the idle set maybe 3 turns in. Ive fiddled with both while running at at times just seems to cause the idle to run off, regardless of turning in or out.
I kept the oem needle and slide(Needle on 3rd position from the top). I figured no harm in keeping the physical top cap and the choke plunger. Simple enough to rule out.
I don't see any oring in the diagram? Ebay carb had one that was destroyed already inside the bowl(pinched between the needle jet and main jet), none in the stock carb at all.
Maybe that's the issue, I've seen missing orings on FCR cabs cause similar idle run away. The manual for these things is pretty sparse.
If you suspect an air leak, put everything together and spray contact cleaner around the intake boot and see if the idle changes.
Post a reply to: JR50 Bogs off Idle/Run away idle