grand dink 125 mmc Workshop-manual : Page 172

          13-2 CARBURETOR
                                                     GRAND DINK125/150DINK125B&W125

TROUBLESHOOTING
                                                 Engine idles roughly, stalls or runs poorly
Engine does not start
                                                  Incorrect idle speed
 No fuel in tank  Incorrect idle speed
                                                  Rich mixture
 Restricted fuel line  Rich mixture
                                                  Lean mixture
 Too much fuel getting to cylinder
                                                  Clogged air cleaner
 Clogged air cleaner 
                                                  Intake air leak
 Contaminated fuel 
                                                  Contaminated fuel
 Faulty fuel pump
                                                  Faulty air-cut off valve
                                                  Damaged vacuum tube and connectors
                                                  Damaged carburetor insulator


Throttle does not open fully, so engine stalls   Rich mixture
 Damaged vacuum piston diaphragm                  Auto bystarter valve opens excessively
 Clogged diaphragm hole                           Faulty float valve
                                                  Float level too high
                                                  Clogged air jets
                                                  Auto bystarter valve set plate installed in
Lean mixture
                                                  the wrong groove
 Clogged fuel jets
                                                  Clogged air cleaner
 Clogged fuel tank cap breather hole
 Clogged fuel filter
 Bent, kinked or restricted fuel line
 Faulty float valve
 Float level too low
 Faulty fuel pump or insufficient output



Engine is hard to start
 No fuel in tank
 Restricted fuel line
 Clogged fuel strainer
 Faulty fuel pump
 Broken or clogged vacuum tube
 Faulty or clogged charcoal canister



Lean mixture
 Clogged charcoal canister
 Bent, kinked or restricted fuel line
 Clogged fuel strainer
 Float level too low




                                                                                       13-2-3