2001 BF50A #3 cyl running lean

2001 BF50A #3 cyl will not fire unless spray fuel in carb or hold hand in front of carb. Have cleaned/soaked carb in chemtool 5 gal carb cleaner and all looks great. I can spray between intake and carbs towards head gasket and rpms will pick up. Assume there is a vac leak but cant find it. Removed intake and resealed and no change. Is there any way a head gasket can cause this, its the only other place I see back there

My bet is it's not just a vacuum leak, but that's going to need to be fixed too. So starting with that you need to order some new gaskets (2 base gaskets for each carb, and an intake gasket), but before you do that, inspect those black plastic insulators to see if they're cracked. While you're at it, the vacuum lines are old enough to start causing trouble too. Check 'em out, or better, replace them.

THEN, have another go at that #3 carb. There a small brass tube that runs from top to bottom right in the middle of the float bowl. In the bottom of it, there's a really tiny jet that's all but hidden from view in the bore of that tube, and gas MUST flow through it if the carb is going to supply any gas on the idle. When you're done you should be able to hold the tube up to a light and see through it - assuming you have your glasses on. It's a REALLY tiny hole! DON"T force anything though it, unless you can find something about the size of a whisker hair. I use ONE strand of one of those dollar stainless wire brushes you can get at Harbor Freight, or maybe Home Depot.

At the top of this same tube, there's a tiny O-Ring. It MUST be in good shape to seal properly so the carb can suck fuel through this tiny jet you just cleaned!

And last, the O-ring on the idle mixture adjustment screw. If that's cracked or dried out/not sealing, that can create a vacuum leak.

Don't feel real bad if you don't get it on the first try. When I started doing these, sometimes it was the THIRD try that was the charm. Have patience!

Best of luck!

Thanks Alan that is some great info. I can see thru the small jet in tube and did use a very small wire to run in it. The oring on it is good as is one on mixture screw. I can spray directly on base of carb at plastic spacer and it makes no rpm change so I figured leak was not there. I removed the vac tube and short vac lines on back side of carbs and plugged and checked with vac pump and had no leaks. I replaced intake gasket. If I spray higher behind #1 and #2 carbs directly on head gasket it seems like when in runs down to #3 you can hear the rpms pick up greatly. I just dont know how a head gasket could cause this. I know a head gasket could leak water.oil or cause a compression issue but could it cause this.

Agreed. It's not likely a head gasket that's leaking.

I swapped #2 and #3 carbs and problem moved with carb so it definatly is problem with carb. Have soaked numerous times and cannot find anything wrong in carb. #3 carb is no longer available. Am going to order #2 carb and change throttle arm and add idle screw and replace all gaskets. Did I mention I hate 4 strokes

Ok so I got a #1 carb and had to change the throttle shaft and bushing, drill hole for choke rod and drill and tap hole for idle screw. Replaced all gaskets and now motor runs on all cyls. good. What a PITA!