I have a Craftsman Blower/Vac Mulcher. 32cc, 170 MPH, 360 CFM. I can get it to start just fine and it will go to full RPM when I hit the throttle but weather it is full throttle or just idle, it will kill after about 5-7 seconds or so every time. the choke is off and the gas is new (few months anyway). What could be the problem and what should I try? Thanks

crigby

Hi,
I would say it is the inlet screen in the carb; could be the fuel filter, but that is the second choice. Thet would be #5 in the picture.
You stated too little info to go beyond there.
Peace,
Clarke

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tmeyer01

I pulled that side off the carb but the screen appears to be fine. I blew through it ok. This picture appears to have one more piece than what I found. I took off the very outside (left in this picture) and inside that was a black gasket and inside that was the screen and main carb housing. This pic shows another layer. Anyway, that appears to be clear. I removed the fuel filter in the gas tank as well and that seems clear. I put in brand new oil and gas but I still have the same problem. It doesn't matter if I have it at full throttle or just idle, it will run fine for about 5 seconds and then just die. I've attached a picture of where I was at.
Thanks,

Attached Images

 

crigby

Hi,
The piece you have between your finger and thumb is actually two, a gasket and the fuel pump diaphragm. I see some deformation there.
I would check the other side of the carb to see if the metering diaphragm is stiff. It must be completely supple to meter properly. If you can grasp the disc and wiggle and hear any sound of it moving (like a "crinkle") it si the culprit. Four small screws at the corners. Carb is a WT model and uses a K20-WAT kit.
Peace,
Clarke

tmeyer01

So I grabbed the disc and moved it and I can hear it kind of pop in and out. (like a jar top after the seal has been broken).

I should replace then that by getting a new kit? Just want to make sure.

Thanks,

crigby

Hi,
The kit is to safe way. I have done it many a time; but I was part of a repair facility and that was my job. I do not think I was often wrong; but I know I was on very rare occassions.
Best of luck
Peace,
Clarke

tmeyer01

I received a kit and replaced the screen, the metering diaphragm, a gasket, and the fuel pump diaphragm but still have the exact same issue. It will start and run perfectly fine for about 5 seconds and then die. Any other ideas?

Thanks,

crigby

Hi,
Only one thing can be the cause; air getting into the sytem where it should not be. The view point(s) woulb be:
1) Air causing an insufficient vacuum to run the pump side; caused by the mount flange that attaches to the crankcase and having the carb attached to it being loose.
2) Air entering the metering side where it must always be liquid. This could be caused by a crooked gasket, folded diaphragm, check valve in the main jet not sealing completely at the right time. The last one has become the bane of the mechanic in recent years. Solved by spraying aerosol carb cleaner through it to clean it , and (this is Important) followed by WD40 or something like it to flush the carb cleaner out.
3) A hole in a fule line, bubbles should be visible in this case.
Peace,
Clarke