Cadapult
XS400J Medic
Sorry for what will be a long post, but I need some advice. I've had the carbs off my '82 Maxim 5 or 6 times now (I've lost track) with cleaning, replacing o-rings, cleaning, adjustments, and more cleaning. My baby still won't run quite right. Starts easily with the choke on, but will stall the minute I touch the throttle. A spritz of carb cleaner in the intakes & the idle increases 300-400 rpm and I can hit the throttle and wind it up to 5k-6k. As long as I don't let off the throttle completely it'll run along fine, but let off the throttle and it idles back to 800rpm and dies if I try the throttle again.
I've got good flow thru the air screw ports, the three little bypass holes in the throats, and every removable jet is clean and clear. The pistons and diaphragms are perfect. I hooked a shop vac to the inlets and the pistons would rise to match the vacuum. Every passageway seems clear. The only openings I'm not sure I'm getting carb cleaner/air thru are the brass tubes (overflow?) that project down into pockets in the float bowls.
From what I've been reading here my suspicion is it's running lean. Would an engine without the air filter installed run as I described? I had corked-up all the leak points at the air box, with no change. Adjusting the air mix screws out between 2 and 4 turns doesn't make a difference. I'm at a bit of a loss, and hope one of the pro's here has some suggestions.
I've got good flow thru the air screw ports, the three little bypass holes in the throats, and every removable jet is clean and clear. The pistons and diaphragms are perfect. I hooked a shop vac to the inlets and the pistons would rise to match the vacuum. Every passageway seems clear. The only openings I'm not sure I'm getting carb cleaner/air thru are the brass tubes (overflow?) that project down into pockets in the float bowls.
From what I've been reading here my suspicion is it's running lean. Would an engine without the air filter installed run as I described? I had corked-up all the leak points at the air box, with no change. Adjusting the air mix screws out between 2 and 4 turns doesn't make a difference. I'm at a bit of a loss, and hope one of the pro's here has some suggestions.