echo pb-500 backpack blower bogs at full throttle

[backhoelover]

ok
air vanes on side should be 0.43mm to 0.88 above mounting service
here is pic for reed valves

 

[JONSSTIHL]

I ended up breaking down and taking it to the dealer. It was sucking air when we pushed the primer bulb so we swapped another new fuel filter on it and it seems to be running better. by the time I brought it into the dealer I had fiddled with it so much that I didn't know if the fuel filter that was on it was the new one I had just replaced or if I had gone back to the original one while trouble shooting.

I need to go back because it is a little too rich. it is turning 6100 rpm at wot and it should be 6800 rpm.

At this point I would pay 50 bucks for a micro d head screw driver but I can't seem to find one.

 

[JONSSTIHL]

thanks for the info on the reed valves. I was wondering what those little black boxes looked like on the Inside. Any adjustment possible or is it replace with new if not within spec.

 

[backhoelover]

I'll send u the link to show u where u can buy single d carb tool when I get home from pc

 

[backhoelover]

you get my info from carb tools

 

[JONSSTIHL]

yes thank you very much, they are more expensive than I thought but it sure beats another trip to the dealer

 

[backhoelover]

I forgot to send u the service data for that unit i will when I get off work

 

[backhoelover]

here you go i can get small single d carb tools who wants to buy one

 

[backhoelover]

check out my pic that is my carb adjusting tool collevtion

 

[backhoelover]

 

[JONSSTIHL]

thanks for the info, I stopped by my local dealer and he could get me the 91059l for 25$ so I jumped on it. I didn't need the large D screwdriver so the 91100 was more expensive.

I couldn't find the 91059L anywhere online

 

[JONSSTIHL]

got my screwdriver last week and finally got around to tuning it. anyone have any idea which screw is the H and which one is the L

 

[z71mike]

Use the process of elimination.

 

[JONSSTIHL]

she is doing it again. and I can't remember what fixed it the first time but I will check the adjustment again. anyone have any idea which screw is the H and which one is the L.

this is really troubling because the problem is so intermittent it isn't funny.

 

[LegDeLimber]

If memory serves me, the High is closest to the engine. Low is on the left towards air filter.
My pb-500 is out on loan to a friend, otherwise I'd could just go take a quick look.

After I changed the metering block of the carb, it quit fighting me and I sort of drifted off to other things.
https://www.arboristsite.com/commun...s-at-full-throttle.263144/page-2#post-5039226

Prior to that I had made sure the reeds (all three locations) were pretty flat and had no bad gaps at rest.
The intake reed had one petal that sat a bit open, so I flipped it over.
hmm, doing This actually put the burr side -away- from the reed block too.
As you would expect, that made cranking the blower noticeably easier.

Do NOT forget to use a thread adhesive IF you so much as touch the reed screws!
Clean and de-oil the screws (and the holes) before applying the it, or it won't hold.
Failure to do this properly, will very likely result in a destroyed engine when a screw comes loose.


A touch heaver than 50 to 1 for the fuel oil mix helps keep the reeds "wet" and sealing better.
I've used 3.5 ounces to a gallon (Echo Red Armor oil) and for the last few years am pretty content with how things .....start, tune and run.

 

[JONSSTIHL]

thanks for the reply, I usually mix my fuel 45 to 1 just to be safe and I haven't fiddled with the reeds yet. I saw a youtube video where the guy said the H was closer to the air filter so i went with that and seems like that worked. my L jet was a little off and come to think of it. since the last dealer adjustment It would take maybe a minute to clear out after starting with the choke on. I would seem to run a couple hundred rpm lower for about a minute then go back up to regular rpms.

I moved the H jet around a bit to clear out any possible blockage but the L jet seems to make the most difference. used it for maybe an hour today and it didn't bog. hope it is fixed.

 

[backhoelover]

Which carb is in the pb500

 

[backhoelover]

Need go pull carb and check little screen inside. There bad about swelling shut on walbro’s. No so much on zama

 

[LegDeLimber]

Bugs me that I'm probably backwards on the needle positions.
(forgetting a little too much nowdays) Would of sworn that I had photos of my efforts, but now I can't find them.

Carburetor is the WLA-1. Don't know why I can't find an image with the needles marked for h & L. Seems like most listings even skip them in the parts numbers list.

I see there's an aftermarket carb now.
https://www.amazon.com/KIPA-PB500-PB500T-PB500H-EB508RT-x/dp/B078V3F8S1

Last time I checked (a few years ago), Walbro wanted about 8~9 times that much for the OEM unit.
Walbro made 4~5 venturi sizes in that body style. All of them were danged expensive then.
Yes, the blower has the smallest one. I thought about opening the venturi size of mine, But was too expensive if I goofed it up.
A new carb cost almost as much as a running blower was worth (at that time).

 

[LegDeLimber]

Just saw my inbox. Thanks backhoelover !
Yeah I had the order of the needles backwards. Low is closest to engine.

Freaking body aches are killing my rest and ability to concentrate.
Seems like this was stuff I messed with ever week and would not forget.
Then health issues push things aside and before you realize it, the details are slipping away.