Walbro carb problem

[sandspider]

Was that a new carb for £6.08? Bargain!

[openspaceman]

8 minutes ago, sandspider said:

Was that a new carb for £6.08? Bargain!

Yes, it took a couple of weeks to get here and it is a very similar copy of the original Walbro, less well finished on the mating surfaces but gaskets make up for that, the purge line spigot  is a slightly bigger diameter and has a right angle that needed adjusting but after that it fitted okay.

 

I'll see if I can use s slide hammer to remove the check valve that was faulty on the Walbro but I suspect even if is available as a part it will cost more.

 

This is the second cheap chinky carb I have used, the other is still going strong on my Sihl HL75 long reach hedge cutter which I need a new gearbox for, it has a nasty Ryobi one on in the meanwhile.

[bmp01]

14 hours ago, openspaceman said:

I did as you suggested, put it together and with the tube to the purge bulb blocked it would run on choke and as soon as the throttle was opened it ran for a couple of seconds and died. It seemed as if the vacuum when the choke was on filled the diaphragm chamber but once the saw was running on throttle the chamber empted and the impulse wasn't able to refill it.

 

Bearing in mind it ran fine with the carb from a working Einhell.

Well, saw is fixed with the new carb so its no longer going in the skip - thats a good thing.

As for the above - I agree with what youve said.

Ref the video of it:

- Most saws die on choke with over rich mixture (not all, but most).

- Didnt revup properly once throttIe was opened, think it was just spooling down from there with out any more combustion.

I dont think it had a full metering chamber of fuel (after runniny on choke), I'd guess its pulling in fuel and air into the metering chamber while on choke and thats why it kept running (on choke) and didnt  die (over rich). Its just that on choke theres such a high vacuum on the fuel circuit that even with an air leak there is still enough vacuum to pull some fuel though.

Either that or the diaphragm's too stiff or wrong version and just not operating the metering arm.

 

But anyway all somewhat irrelevant now. 

 

 

 

Edited February 2 by bmp01
Clarifications