Remove the bottom part of the carb. There is somewhere, usually originating at the mouth of the carb, a vent to equalize the float bowl pressure to the air pressure outside. If that is plugged the carb will flood no matter what the float condition is. Spent hours finding that one once. Remove the pin (#32 in the part breakdown provided by KSellon) that the float hinges on and remove the float (#31). Careful that you don't lose the needle (the little thing at the bottom of assembly #52). Shake the float and listen for sloshing. Sloshing is bad and indicates that your float has sunk, get a new one. Reassemble the float and needle, sometimes the needle has a little wire bale that has to hook over a tab on the float. The float should move freely throughout its range of motion. Gently raise the float until you feel resistance. The floats should be about horizontal at this time, if not carefully bend the float arm until they are. This is approximate, there is actually a measurement from the carb to the top of the float to set it exactly but I don't know it's value. Extinguish all fire for the next step (you should have done that at the beginning). Hold a pan under the carb, open the fuel cutoff valve, fuel should come out, raise the float till you feel resistance, fuel should stop. If it doesn't the needle and seat (assembly #52 should be replaced). The needle and seat assembly is inexpensive and probably should be replaced anyway. Reassemble. Good luck.
Bill
Marvel rebuild kit # K2033 $22.00 from AEI here in Oklahoma. Comes with gaskets, needle and a couple of the seats. 405-236-3551 ext 2. The float for a TSX979 Marvel carb is part# C85-148 $16.00 with the same company.
I'm still having a problem getting my machine to fire over. It's turning over and firing, puffing small puffs of gray smoke, but doesn't seem to catch and start up. This was after jump starting with a car.
Does anyone have any suggestions on why this might be happening? I feel like I'm finally close to getting the machine running again.
I appreciate all the help given so far.
Weak coil, bad plug wires, dirty points. Open up the distributor and check for good clean contacts.
Thanks for your response. I just put on new plug wires and distributor cap yesterday. I actually had it running earlier this afternoon. I tried starting it a few hours later and it turns over, but still doesn't fire up. I tapped on the carburetor, re-checked all my connections and I just don't understand why it won't start again!!
What are the points gapped at?
it's a 1973 sa 200 (f163) so yes, i got it to fire over and isolated the problem to the carberator and just today got my rebuild kit in the mail. so ive been tinkering with my other machine, stairing at my disassembled carb every night.Finally time to put it together! I thank everyone for ther responses , ive learned alot about that damned little marvel sheb carb .
Dont forget to check your air cleaner, they can fill up with gas when the carb floods. Set the float level to 1/4" measuring from gasket. Set mag points to .015 , Use Champion U16 or UD16 plugs gaped at .025
I just rebuilt my marvel on my 47' and the zenith on my 56', the exact float measurements taken with the float attached to the top part of the carb, and the whole unit turned upside down, and with no gasket are: Marvel-- .250" from the surface of the carb to the UNDERSIDE of the floats. Zenith-- 1"+5/32" from the surface of the carb to the TOP of the floats. Now these are the measurements that were provided with my rebuild kits, I know my explanation isn't too clear but if you buy a rebuild kit they explain it a little better than me, and if you're in a jam with a leaky float and you've found a hole/crack, u could drill a tiny hole, drain it, and re solder it up.