CV15S start=sputtering, backfire, surging. Fuel off=runs great then dies (obviousy)

[MattG.inAZ]

Hi all. Newb here. Got a CV15S, don't know age. Not much to go on as to model etc. Lt of new parts on ignition. New fuel, tank and tubes. When starting it pops, sputters, may backfire and actually runs pretty ragged. Reduce power from choke position and engine dies. While engine is running, turn off fuel supply. Engine starts running great with no misses. Have not adjusted valve last yet. Replaced carb (and lost old carb when someone came to help and took it) with after market from ebay ($20). I figured float level. Removed bowl and it looks ok but float is plastic so no adjustment available. I Hope this explains my situation. I'm stumped.

Any ideas out there?

thanks
MattGinAZ

 

[Rivets]

I’m guessing aftermarket carb bad, engine running rich. Aftermarket carbs are a crap shoot, unless you buy from reputable dealer.

 

[bertsmobile1]

It is not uncommon to get a Amobay carby that has been assembled with the wrong needle so it never cuts the fuel off properly,

 

[Scrubcadet10]

I'd Remove the float bowl off the carb, turn the fuel on, and lighlty push the float up until and/or see if it cuts off fuel flow. or how high it gets before the float shuts fuel off.

 

[Fish]

Put up the spec. numbers please.

 

[StarTech]

The CV15 is know to have needle/seat problems with the Walbro carburetor that is why a pressure test of the carburetor is done. IF it fails the pressure a new needle and seat are installed per the instructions included in the replacement kit. I have replaced several of these needle seats over the last 7 yrs. The pump fed carburetor are the worst leakers when compared to the gravity fed versions but both can leak.

 

[MattG.inAZ]

still working on it. Trying to get float that can be adjusted (replacing 1275702s).

 

[Fish]

still working on it. Trying to get float that can be adjusted (replacing 1275702s).

No spec. number?

 

[Scrubcadet10]

 

[MattG.inAZ]

No spec. number?

well, the original carb is missing. There are no tags on engine or tractor. I figure float is 12-757-02-S. CV15s GT2000 craftsman. How ro adjust float level on all plastic float. Going to try a 2575709 wirh metal tang.