Export thread

Craftsmen B&S 34cc weedwhacker

#1

L

Led 67

Recently I just scored an older weedwhacker from an auction for a ditch cutter I have removed the carb carefully cleaned it and replaced the fuel lines as well as the primer bulb and now it will not even prime it almost sounds like I am sucking air when I try to prime the carb I have checked and rechecked my work any help will be appreciated


#2

B

bertsmobile1

Did you replace the fuel lines onto the correct spiggots on the carb
The one closest to the bulb is the return and the one furthest away is the supply.
I have a golden rule for cube carbs
If they are opened up then both diaphragm & gaskets get replaced
If the metering valve needle has to come out then it gets replaced as well.
A lot of them look real good till you see them under 100X magnification.


#3

ILENGINE

ILENGINE

For me the cube style carbs with a primer system don't even get opened, they get replaced. Just too many cases of opening the carb, doing the normal cleaning installing a repair kit only to find out that the check valves are now stuck open and it won't prime or the main jet check valve has stuck shut and now won't start because of no fuel getting into the engine.


#4

StarTech

StarTech

Many DIYers think that remote primers pushes the fuel into the carburetor which they are not design this way. They meant to remove air from the fuel chamber while pulling fuel into the carburetor.

Also many uses carburetor cleaners that are design to be used on these cubes. They have delicate internal check valves that can be destroyed the use of the carb cleaner with wire probing and use of compressed air (used very close) being a is a no no.

I have been cleaning these cubes for over 12 yrs now with about a 98% success rate. I strictly use an ultrasonic cleaner with soap and water. Usually the only ones that I have priming problems are the Zama cube with build in primers used on Stihl equipment. The only other cube that I have a problem with are the ready start (choke-less) designs where the enrichment valve wears out and they don't enrich.

As always we need the equipment numbers to even start to troubleshoot the problem remotely. We are not magical there beside the OP.

Also did the OP replace any of the cube gaskets and disphragms? Most usually need at least a new metering diaphragm.


#5

B

bertsmobile1

StarTech said:
The only other cube that I have a problem with are the ready start (choke-less) designs where the enrichment valve wears out and they don't enrich.
Click to expand...
And I thought it was only me who could not get these mongrel things to work properly


#6

StarTech

StarTech

bertsmobile1 said:
And I thought it was only me who could not get these mongrel things to work properly
Click to expand...
Nope you're not alone when it comes to ready start cubes. By the time the need new diaphragms there is too much wear and tear otherwise. I don't many of them to work. I even brought the valves just to find the aluminum cylinder it rides is also badly worn. I glad I don't see very many of them. Some of the older trimmers I was able to modify them to have a working choke.


#7

L

Led 67

Thank you all for the replies. I do not use compressed air or direct spray from a can to clean with I disassemble everything in order and soak in carb cleaner and use a wooden toothpick to clear passages I will try again to check everything and let you know how it turns out


#8

L

Led 67

StarTech said:
Many DIYers think that remote primers pushes the fuel into the carburetor which they are not design this way. They meant to remove air from the fuel chamber while pulling fuel into the carburetor.

Also many uses carburetor cleaners that are design to be used on these cubes. They have delicate internal check valves that can be destroyed the use of the carb cleaner with wire probing and use of compressed air (used very close) being a is a no no.

I have been cleaning these cubes for over 12 yrs now with about a 98% success rate. I strictly use an ultrasonic cleaner with soap and water. Usually the only ones that I have priming problems are the Zama cube with build in primers used on Stihl equipment. The only other cube that I have a problem with are the ready start (choke-less) designs where the enrichment valve wears out and they don't enrich.

As always we need the equipment numbers to even start to troubleshoot the problem remotely. We are not magical there beside the OP.

Also did the OP replace any of the cube gaskets and disphragms? Most usually need at least a new metering diaphragm.
Click to expand...
The diaphragm was still pliable


#9

StarTech

StarTech

Led 67 said:
Thank you all for the replies. I do not use compressed air or direct spray from a can to clean with I disassemble everything in order and soak in carb cleaner and use a wooden toothpick to clear passages I will try again to check everything and let you know how it turns out
Click to expand...
I'm afraid you just ruined your carburetor as there tiny rubber check valves inside the carburetor that can be destroyed by carburetor especially when soaked. NAd I know as I destroyed several about 12yrs ago when I started repairing these cubes then I got my first USC, now I only clean with soap and water the lightly air dry them.


Footer Links 1

Top