Walbro WA Carb Problems

[matt9923]

The funny thing is that the manual said to not use any cleaning agents or anything, just plain water. At the HF store, they had an ultrasonic cleaning powder right next to the machine.

Who knows. I have herd many things, kerosene, mineral spirits, purple cleaner ect... water

 

[wigglesworth]

Where is the carb now? Maybe a trip in my new HF ultrasonic cleaner could give it new life.

I have a carb that several trips thru the cleaner couldnt help. I neve did figure out what was wrong with it. The needles and seats looked good, no stopped up passages...its still sittin on the bench. On the other hand, the ultrasonic has done magic on quite a few carbs, but it aint the do all end all fo sho.

 

[wigglesworth]

Who knows. I have herd many things, kerosene, mineral spirits, purple cleaner ect... water

I use mineral spirits.

 

[epicklein22]

I use mineral spirits.

Good couple post here wiggs. I'm gonna try some solvent my dad uses at the printing shop he works at.

Ya, I assume it can't be the end all, be all for solving carb problems. I just hope it earns a keep and justifies the 32 bucks I spent on it.

 

[pioneerguy600]

An ultrasonic cleaner cannot repair a physically damnaged carb.
Pioneerguy600

 

[Methlickman]

Found this thread after spending several hours swearing at/about a Walbro WA. Lots of good answers, but they don't actually solve the problem. What I'm not clear about is which model of the WA is involved - depending which one, they either seem to need, or don't need, the diaphragm under the circuit plate.
Is it possible to identify the model from the numbers on the carb? The Walbro parts lists don't seem to help here

#### Morris

 

[sfpcservice]

I'm having trouble getting the carb on this 020AV right. It's a Walbro WA. The kit I have is for both the WA and WT series of carbs, kit # K10-WAT I believe. My question is on the small plate on the needle side of the carb. Does both a diaphragm and a gasket go under the plate? And if so, in what order? Also, how's the needle lever height set on these? Thanks.

NO CIRCUIT DIAPHRAM.

http://www.arboristsite.com/community/threads/stihl-020avp-carb-question.266936/

Look at the diagram in this post.

I had my 020avp apart about 10 times after rebuilding the carb because it surged at high speed. Finally somebody posted the picture of a WA1A and there is no circuit diaphragm. I think it was just blocking fuel flow. Saw runs PERFECT without it. Also in that diagram you may notice there are 2 diaphragms in the fuel pump side... My saw only had one originally and I replaced it with the matching one from the kit. I think the WA series manual from walbro is a bit generic and shows parts you may not need on your carb. Hope this saves some folks a bunch of time!

 

[JOEY JENKINS]

The carb was bad.

I know this thread is 10 years old but it seems the circuit plate WA-1 carbs experience the same issues, which I have been dealing with as of late. Look at the pics you posted in this thread of the carb where the circuit plate goes. See the two drillings in line with the H screw. One is a direct, unmetered passage to the venturi and I believe that the gasket is supposed to cover that hole. The other one is metered by the H screw. At least I hope I'm right because I'm tired of taking the saw apart and putting it back together over and over again.

 

[m2theb]

I know this thread is 10 years old but it seems the circuit plate WA-1 carbs experience the same issues, which I have been dealing with as of late. Look at the pics you posted in this thread of the carb where the circuit plate goes. See the two drillings in line with the H screw. One is a direct, unmetered passage to the venturi and I believe that the gasket is supposed to cover that hole. The other one is metered by the H screw. At least I hope I'm right because I'm tired of taking the saw apart and putting it back together over and over again.

Did you get to the solution?
dealing with a similar issue now on a G and I’m about to go in for the 12th time and pull the diaphragm and use #2 gasket, page one of the post.
But wondered if there was something definative

 

[m2theb]

NO CIRCUIT DIAPHRAM.

http://www.arboristsite.com/community/threads/stihl-020avp-carb-question.266936/

Look at the diagram in this post.

I had my 020avp apart about 10 times after rebuilding the carb because it surged at high speed. Finally somebody posted the picture of a WA1A and there is no circuit diaphragm. I think it was just blocking fuel flow. Saw runs PERFECT without it. Also in that diagram you may notice there are 2 diaphragms in the fuel pump side... My saw only had one originally and I replaced it with the matching one from the kit. I think the WA series manual from walbro is a bit generic and shows parts you may not need on your carb. Hope this saves some folks a bunch of time!

Did you get to the solution?
dealing with a similar issue now on a G and I’m about to go in for the 12th time and pull the diaphragm and use #2 gasket, page one of the post.
But wondered if there was something definative

Been in out of this G a dozen times
ive thrown in the towel a couple times
I think I discovered the problem and it’s in the rebuild kit.
theres a hole in the gasket that matches a hole In the floor, that’s the old gasket
the K10 gaskets, 1 and 2, don’t have that hole.
but the old gasket back in and it runs. The problem wasn’t idle or acceleration, just in H.
would not be tuned out




oem gasket above from the k10 kit

as found gasket with the hole in the lower right.

 

[Vintage Engine Repairs]

Been in out of this G a dozen times
ive thrown in the towel a couple times
I think I discovered the problem and it’s in the rebuild kit.
theres a hole in the gasket that matches a hole In the floor, that’s the old gasket
the K10 gaskets, 1 and 2, don’t have that hole.
but the old gasket back in and it runs. The problem wasn’t idle or acceleration, just in H.
would not be tuned out



View attachment 859297
oem gasket above from the k10 kit

as found gasket with the hole in the lower right.
View attachment 859298

You’re missing a diaphragm above that gasket mate.

 

[m2theb]

You’re missing a diaphragm above that gasket mate.

Thanks.
that was the next step. I needed to have it off to get a picture the hole needed in the gasket. Kit comes with a couple gaskets, w/ and w/o the hole. Just trying to point out that on this carb, use the one with the hole. That’s what I was trying to say with the picture anyway
it got covered with the diaphragm after and saw runs mint.

Happy Holidays

 

[Vintage Engine Repairs]

Guys just to let you all know the issue, the original diaphragm under that plate on the metering side is 0.15mm all replacement kits (even walbros own WAT-10 or whatever it is) are all .22mm.


The vacuum from the venturi is enough to allow the diaphragm to let fuel in but not seal that drilling and thus fuel is being allowed into the venturi unmetered.

 

[Vintage Engine Repairs]

Ok guys, so I just tested a concept. I removed some of the area where the valve part of the diaphragm attaches to the rest of the diaphragm to allow more flexibility. It fixed the issue, now I get full range of rpm controlled by the H screw. Hope this helps others out in the future. The diaphragm material is incredibly tough and is fibre reinforced, there is more than enough strength to maintain the connection even with 1/2 of the material at the join removed.

 

[m2theb]

Ok guys, so I just tested a concept. I removed some of the area where the valve part of the diaphragm attaches to the rest of the diaphragm to allow more flexibility. It fixed the issue, now I get full range of rpm controlled by the H screw. Hope this helps others out in the future. The diaphragm material is incredibly tough and is fibre reinforced, there is more than enough strength to maintain the connection even with 1/2 of the material at the join removed. View attachment 934923

nice work!
great info to share