fixing up an older mantis tiller for a buddy. replaced the carb on it an the fuel lines. all the lines are routed right. it has spark and compression but will not start.
there are two adjustment screws on the carb. a H and a L . what should the initial settings for these be?
it is a Zama K54A carb.
Thanks.

Can you actually smell gas in the cylinder? Sniff the spark plug after you try to start the motor. If it doesn't smell of gas, then you're not getting fuel. The plug should not be soaking wet, either.

I would try richening the mixture by a half turn each and see if that fixes it, and that is if the plug isn't wet.

Make sure you remember where the needles were set.

got gas at the plug..just not sure if its too much. matched the removed carbs setting but that did not work.

I'm assuming you're not getting anything at all, right? No combustion whatsoever?

Is the plug actually wet with gasoline? If so, you're most likely flooded. If this is the case, you'll need to clear the flood. Remove the plug, clean it up with rags (dry it off, basically), and pull the motor over a few times quickly - you'll probably see some gas spurting out of the plug hole. If you see this, you know you're definitely flooded.

If you experience the above scenario, what you can do is open the throttle to 100% and, without the choke, attempt to start it. Since the choke is designed to richen the mixture (and pull in extra fuel), you won't need it with the internals saturated with gas. It may take quite a number of attempts to start like this but it should eventually start or give you at least some feedback.

Since you said "there's definitely gas at the plug" I'm assuming it's strong enough to smell/see. I highly doubt you're running -too lean- if that's the case. What will usually happen is gas will build up after repeated attempts to start and temporarily overcome the too-lean mixture. Basically, even if it's leaned way out, it will still get some amount of gas in the cylinder and you'll end up with a backfire or a partial combustion or some kind of feedback.

Did you end up tightening or loosening the mixture screws? Tight = lean, loose = rich. If you made the mixture richer it's probably way off at this point. Try returning it to as it was before, then turn each one half a turn inward (clockwise). Attempt to start, making sure you haven't flooded it between attempts, and make another half-turn adjustment.

I should've asked, but, is this a two or four cycle motor? The same principles apply, of course. It would be helpful to know, at least.

Thanks for all your help. It is a 2 stroke. played with the mixture screws (leaned it out) and got it to fire. still not quite right yet since it is still flooding. will have to play with it some more.

ZAMA makes Diaphragm carbs.  I have this carb in my weed wacker.  They tend to get stiff over time.  Search Donnyboy73 on Youtube.  He has videos on how to adjust and fix this sort of thing.

Quote from: oldmech on April 04, 2013, 03:35:47 PM
fixing up an older mantis tiller for a buddy. replaced the carb on it an the fuel lines. all the lines are routed right. it has spark and compression but will not start.
there are two adjustment screws on the carb. a H and a L . what should the initial settings for these be?
it is a Zama K54A carb.
Thanks.

kk. my goped has pretty much identical setup. a walbro wt668a i believe. anyhoo close both screws to right. thenopen up H anticlockwise 1 3/8 turns out, and L 1 1/4 should get you started. then fintetune. 2 fuellines right? one out and one in? those CAN be reversed w/o problems. if backwards it will still run, but not filter.

Quote from: oldmech on April 05, 2013, 08:58:31 AM
Thanks for all your help. It is a 2 stroke. played with the mixture screws (leaned it out) and got it to fire. still not quite right yet since it is still flooding. will have to play with it some more.

Well, you're one step closer at least. Just make sure you keep track of the mixture screw settings. Otherwise if there's an additional problem, you might not be able to return to the proper settings.

turns out one of the gents i work with had worked in his fathers small engine repair business. and he has affirmed the good advice you all have already given. after i get done with my busy work week i will give it another try. it was running before the carb diaphrams decided to give out and leak fuel all over the place.
once again thank you for all your help.

Quote from: oldmech on April 06, 2013, 04:22:16 PM
turns out one of the gents i work with had worked in his fathers small engine repair business. and he has affirmed the good advice you all have already given. after i get done with my busy work week i will give it another try. it was running before the carb diaphrams decided to give out and leak fuel all over the place.
once again thank you for all your help.

Good luck with it!

http://www.ehow.com/how_5880642_adjust-mantis-carburetor.html