Tanaka Backpack leaf blower help (carb adjustment)

[linuxman51]

I'll preface my question(s) and issue(s) with this: I'm not particularly good with carbs. anything with fuel injection, I've got that, no problem, good to go. but carbs.. I understand the principles upon which they work, but apparently when the rubber meets the road they may as well be built with black magic and voodoo :confused2:

So I've got an older tanaka TBL-505 backpack blower, it sat for a number of years (decades?) after the fuel tank split while I was still in highschool (I'm 33 now, so.. it's sat for like 15 years). I finally got off my duff, ordered a new tank for it, and decided to put it back into service.. got fresh fuel in it, spun it up with the drill, and watched it flood out almost immediately and blow gas back out the carb inlet. so.. off with the carb, check it out, clean it up, took the top and bottom off of it to make sure the screens, etc were clear, and it was surprisingly clean on the inside. something about ethanol, but I digress.

After a few days of on/off work, I finally tracked down the model number for the carb, it's a walbro HDA (51-1 or something discontinued), and futzed with the idle and high speed screw settings. This is what I've arrived at: It seems that I can adjust the idle screw and get it to consistently start and idle (yay!), but the High speed screw has to be closed. if I open the high speed screw, it will run out just awesome, great power, force overwhelming out the tube, blowing leaves has never been so easy :cool2:

however, the problem comes when I shut it off and attempt to start it again... it floods out. I can close off the high speed screw and it will start and idle fine just about every time (using the pull rope or the drill). if I have it set where it will run out high and sorta idle well, it will not start, and in fact will almost immediately flood out regardless of whichever method I employ to get the desired result.

there's not a lot of 'stuff' in this carb to adjust/go wrong. the flaps/screens/etc all were in very good shape when I had it apart, and it doesn't leak after you shut it off, so is this just a matter of me not getting the two magic screws set juuuuuust right? or should I order a rebuild kit anyway? (or is something even more sinister going on here?)

thanks!

 

[RandyT]

I am not familiar with your model, but does it have a primer bulb. I have seen cases where the valves in the primer would stick open, which will allow fuel to back flow into the carb, causing a flooding situation like your describe. Will empty the fuel tank in some cases. I would also consider a rebuild kit just to be sure, and make sure the carb is clean, possibly needle valve not sealing.

 

[linuxman51]

it doesn't anymore.. I don't remember taking it off in the distant past, but there is a line floating around in free space with nowhere to go. it doesn't leak fuel though. is that something I can block off (for troubleshooting purposes? )