Question: The carburetor rotor (barrel with a large hole in it, visible by looking down into the throat of the carburetor) is difficult to rotate and feels rough when I do get it to move. What is causing this and is there anything that I can do about this?

Answer: In the vast majority of cases this is caused by a bit of dirt or debris having worked it's way into the carburetor and lodging between the rotor and the carburetor body OR the idle stop screw and a piece of grit acting to bind the rotor. The solution is in flushing away the grit so nothing can act to bind the rotor from rotating OR the idle stop screw not seating properly in the rotor slot.

Procedure:

1) Please consult your owners manual Pages 6 and 7. You must be able to consult the owners manual to carry out this procedure. If you have misplaced your owners manual, you may download a copy of the manual from www.richmondrc.com/support.htm > VMAX Information.

2) Review the engine 3-View illustration on Page 6. Remove the carburetor from your engine by loosening the nut on the end of 2090 and gently rotating the carburetor to and from while pulling  the carburetor gently upwards and out of the engine.

3) Review the exploded carburetor 3-View illustration at the bottom of Page 6. Carefully remove 3080 (Idle stop screw) and then remove the entire assembly consisting of 3060, 3050, 3040. Then remove 3030 (spring). Flush the carburetor with clean fuel several times ensuring that you flush down through the hole vacated by 3080 and flush the area vacated by 3040. Lubricate the hole for 3080 and lubricate the area vacated by 3040 with After Run Oil.

4) Reassemble the carburetor carefully. First install 3030 (spring) noting that the wider end of the spring goes into the carburetor first. Then install the entire assembly consisting of 3060, 3050, 3040. Rotate this assembly so that the slot in 3040 aligns with the hole for 3080. Install 3080 (Idle stop screw) and tighten it so that it is snug on the washer. Do NOT overtighten 3080... this is not a farm tractor... it's a precision fitted model airplane engine. Snug is good enough... leave your pipe wrench in the garage! If you find that the head and washer of 3080 will not seat against the carburetor body, back off 3080 and realign 3040 slightly and try again. 3080 must engage in the slot of 3040.

5) You should now be able to rotate the carburetor rotor freely. If you find that the carburetor will not rotate or remains tight and rough, you will need a new carburetor assembly #463000.