Craftsmen weed wacker carb issue.

[strtspdlx]

I've had this thing for awhile. Never ran right. And it ate the fuel lines up. So I replaced them and put in a carb kit. Now if I try to start it it won't. I do it exactly as the instructions say and nothing. Here's the fun part. If I pull either the fuel supply or primer line off the carb it'll start and run for a second or two. Then nothing. I have to prime it again and remove the lines (either of them) and it'll do it all again. I'm 100% positive the carb kit is correctly installed and I am getting fuel to the diaphragm if I prime it and move metering lever by hand. I am not getting fuel in the primer line or the build. I feel like I have a bad one way valve in the primer block on the carb. It's a zama w19 71a


Regards-Carlo

 

[backhoelover]

but a new carb is the only fix you can try to spray valve with wd 40 and get it working again but it will do it again there is also 3 other numbers you are missing for the zama carb sorry you bought a kit

ex
c1q
c1u
c1m
rb etc

 

[backhoelover]

zama tech guide

 

[backhoelover]

sounds also like it is putting pressure in the gas tank that is the only reason you are getting fuel

 

[strtspdlx]

Yeah. The primer is working to an extent which is why I'm a bit confused. I'm curious if the one way valve is just clogged up. Or maybe me blowing air through it destroyed it. As I didn't know there was a one way valve. I have other carbs I can put on it and it'll start and idle perfectly. Maybe I oughta just put them on and tune them in. It's a cheapie weed wacker but my grandfather gave it to me so it has some sentimental value to me. If I can I'd like to keep it going.


Regards-Carlo

 

[strtspdlx]

I believe I fixed it. I took it apart and worked some brake clean into the one way valves to check for proper function. One was stuck open it seems. Or it was intermittently opening. Cleaned it out and now I have fuel in the primer bulb.


Regards-Carlo
Edit: also I believe it is a c1q carb. But don't quote me on that. It's been awhile since I ordered the parts.

 

[backhoelover]

good glad to hear if you need any helps just let me know

 

[strtspdlx]

Yes I do. I got it to some what start and run. It'll start if I have it turned upside down for a couple seconds. If I flip it right side up and start it. Which is always first pull it'll run for 3-5 seconds and die. However if I flip it back over. Fuel cap facing ground. It'll stay running. I checked the pickup to make sure the filter is still on it and it where's it supposed to be and it is. I know it's not picking up fuel. But why when it's turned upside down does it work??


Regards-Carlo
Edit: started playing with the adjustment screws. They started at 3/4L 1H. So I fiddled with them and got it to idle somewhat. I had to adjust the high speed with it held wot but it finally has high Rpms. Which it never did before. If I return to idle it will idle with no fluctuation for anywhere between 5-30 seconds and then it just straight dies. Doesn't indicate any lean or richen condition. Bogging or rpm increase. It just dies. The more I richen the L needle the more it seems to idle longer.

 

[backhoelover]

it has to be at operating temp to start adjustment to be honest sound like there is a leak in fuel line or the nozzle check valve just need a new carb to be honest if you buy a check valve you will have more then what a new carb cost also if you work on your own stuff you need to build you a pressure tester unless you have a mity vac or just go to harbor freight and buy one

 

[backhoelover]

you have that simple start carb with the 2 plates on top. here is how to test check valve
1. remove meter plate and diaphragm
2. remove h needle
3. install a small piece of fuel line into where the h needle screws in
4.place you finger on any holes that are on the l h needle side that feed the h and l needles
5. put your mouth on the fuel line and start to suck, if you can't suck it is good, if you can it is bad. now blow if you can blow it is good if not it is bad

page 15 tell you what i have just told you in more words all carb with nozzle work this way it also cover the capillary style too you can read the whole manual and it show you other test that you can do

stihl have a master test for carb but i will need you email address to send cause it is in work and wont let me link on as website

 

[backhoelover]

make sure you have enough gas in tank

 

[backhoelover]

those carb a hard as heck to adjust. i notice that if you dont have the adjustment tools and using pliers there hard and heck to get just right do you have the tools if not you can get a set from dave for 22.00 shipped that has all the major adjuster in the kit

 

[strtspdlx]

I just took my dremel with a cut off tool and made slots in the needles to adjust like everything else I have. Sorry I didn't read that far into the manual I just read the basic functions part. I will pm you my email address. You can never have to many diagnostic sheets. Also I do have a pressure/vacuum tester. I put 10psi on the needle and seat and it held fine. I will redo to do confirm on Monday or Tuesday. Thanks for all the help.


Regards-Carlo

 

[backhoelover]

you want to took up tester and on inlet side pump up and press p bulb make sure it drops in increments and then on the return side hook up pressure tester and pump the p bulb to make sure it build pressure and holds. dont pressurize return side!!! as the p bulb will