Walbro HDB help

[JonCraig]

Craigslist find Poulan 4000. Walbro HDB carb. Took it off to do the usual clean & carb kit and noticed that the Low adjust screw is obviously different than the High, and has a different taper on the end. I know some carbs have different tapers on the needles and some are the same. I seem to recall a previous HDB having identical needles. Further, in the IPL for this saw, it lists the same part number for Hi & Lo screws. Pictures:







So I'm assuming that the redneck who had it before lost/broke the L screw and replaced it with another one. Not too surprising, seeing that I found the metering diaphragm on the wrong side of the gasket. Doesn't seem like a guy who paid attention to details.

So, oh wise AS members, do I try to source a correct Lo side needle from a 30 year old carb? Since it's the Lo, is it not as big a deal? Or are they, in fact, different needles (that just only came as a pair in the IPL?) and maybe in a later revision of the part they didn't have the long, long head that they did originally? I ask you guys because you're way smarter than I am.

Thanks in advance!

--JC

 

[AVB]

The pn listed in the Poulan IPl is for both needles. I tried looking any of the HDBs at Walbro but the website is currently for me. Please the complete HDB model and someone should be look it later when Walbro's site comes back online.

 

[JonCraig]

Carb is an HDB 8C

The Walbro part number for one of those needles is 102-233-1, and is ~$30. Thirty dollars? Double you tee eff?

 

[JonCraig]

Maybe a more generalized question would be: How critical is the shape/angle of the taper on needles?

 

[rynosawr]

The high and low needles are definitely the exact same size, as I just rebuilt this exact carb for a 3400.

 

[Terry Syd]

The taper is not critical to tuning. It is only used to set the adjustment to around 1 to 2 turns out. If you can tune it easily, then don't worry about the taper. If you had less than a half a turn, you might consider using a slower taper needle to make adjustments a little easier.

 

[JonCraig]

Any advantage/disadvantages to using the "wrong" screw on the H instead of the L? Seems like it would make adjusting the idle easier, provided that I didn't lean out the H side with the wrong screw, of course.

Does it strike anyone else as insane that this adjustment screw is $30? When one for an HDB-6 or -7 is literally 1/10th the price? I know $30 doesn't break the bank, but a $30 screw for a $50 just seems wrong...

 

[rynosawr]

I don't think you could hurt anything by trying out the needles you have and see if you can get it to run right....

It ain't exactly a v-12 Ferrari with 6 2 barrel carbs on it.....

It is a poulan


And yes, $30 seems like a misprint for the price it is so insane

 

[JonCraig]

Don't mock my green monster!