Red Mercury
Member
I have a WD-9 that starts very well on gas but it runs very fast (1500+ RPM) which is not normal. It has been this way as long as I have had it so I decided to clean up a spare carburetor and swap them. When I took the old carburetor off the mystery was solved. It appears that the air valve (round disk) and spacer have been removed as well as a couple of other modifications. I then decided to dig deep into my spare parts and found two more WD-9 carburetors that have had the same modification. It appears that this was done to make the engine run faster and possibly start easier on the gas side. I did install my refurbished carburetor and now the tractor runs much slower on the gas side (normal). Is anyone familiar with this modification? I am wondering if it was done many years ago by a local IH mechanic in my area since I have several carburetors on hand with the same modification.