Stihl 028 AV Wood Boss Carb trouble

[bottomcat]

Cliff notes: Dealer says it needs a new carb but can't get one. He rebuilt mine but it runs worse now than it did before. Mine has a Walbro carb and the only replacements I see online are Tillotson. Are they interchangeable?

Long version: I am a complet novice when it comes to saws. This saw belongs to my dad who bought it out of a pawn shop just after Katrina. I took the saw to the local Stihl dealer and told them I wanted the chain sharpened, the carb adjusted and to check out the choke/run/kill switch. (It seemed to me as if the switch was not working correctly but I don't remember the details of why. It was early summer when I last used it.) The saw was running and I had done some cutting with it early summer but it wouldn't idle properly. Sometimes it would idle but more often than not if you engaged the chain brake and took your finger off the trigger it would die.

I called after a couple of weeks and that's when I was informed that they no longer make a carb for my saw and that he had ordered a rebuild kit to try that but no guarantees. (WTH, if i say adjust the carb and you decide it needs replacing maybe that's something you should call me about beforehand.) I call back next week and he says kit is in but will be a few days before he can work on it. Call back 8 or 9 days later and he says "just got the rebuild kit in, will work on it in a couple days." WTH again. He denies remembering our earlier convo. Another week and he says the kit didn't work but he hasn't given up yet. After another week he says he can't fix it. He says compression is good, good spark, everything looks good, just won't run. (I have by now lost all confidence in this guys ability.) edit: the last time I talked to him he said "I have filed this carb everywhere I know to file a carb and it's still not working. I have no idea what he was talking about.

Now it will start but will not run long enough to even begin cutting. Just kinda chokes out or acts like it's not geting fuel. When it does start for any length of time as soon as you disengage the chain brake the engine revs to full throttle and the trigger has no effect at all.

An experienced tree guy took a look at it today. He poured out the fuel and added fresh. Checked the fuel filter and said it was clean. Took the breather off and inspected around the carb said he could see no evidence of fuel leaking anywhere.

I took the carb off and and was a bit concerned about the look of the intake. As you might can see in the last pic the intake is out of round and one side has been a bit mashed.

Any input or advice appreciated.

 

[ashy larry]

Probably causing an air leak.

 

[Mad Professor]

Is the spark screen on the muf clogged up?

 

[bottomcat]

Probably causing an air leak.

assuming you're referring to the deformed intake. Is that (an easy) repairable by a "just somewhat" mechanically inclined noob? Is it worth taking to a "reputable" service repair shop?

Is the spark screen on the muf clogged up?

That hadn't crossed my mind. I will check it/clean it. I've done that on my echo weed eater, i'm assuming it will be similar on the saw.

thanks.

 

[axlr8]

Give me a few days, I might have a carb for you and that intake piece. Im assuming this small engine guy is an idiot.. from what you are telling us.. I wouldnt take anything back to him.

What your describing sounds alot like a carb issue to me..

 

[Mad Professor]

Looks like a Gorrilla used a channel lock to pull out the metal insert on the intake. Replace it or see if you can bend it back to shape. Might cause a leak?

 

[71dart]

That little intake sleeve is pn 1113 141 1805 and it could be causing an air leak.
I'm not sure if there's a performance difference between the carbs but the tillotson will bolt right up in place of the walbro.

 

[a. palmer jr.]

I know Stihl doesn't use a gasket between the carb and manifold but on older saws I usually put one on them.

 

[bottomcat]

Thanks for the replies thus far. Is the r/r of the intake sleeve a simple task? and how would one go about performing that task? thanks again.

 

[Mad Professor]

Thanks for the replies thus far. Is the r/r of the intake sleeve a simple task? and how would one go about performing that task? thanks again.

It is supposed to be circular without the plier mark. How are you at fixing bent metal?

 

[71dart]

Yes, it's very easy. Just pull the old one out and push the new one in.

 

[bottomcat]

It is supposed to be circular without the plier mark. How are you at fixing bent metal?

Yes, it's very easy. Just pull the old one out and push the new one in.

I don't know if I'm any good at it or not but if it comes out easy enough it won't hurt to try. I don't think I can't screw it up any worse than it is now. and maybe that's all that it needs. If I can straighten it out any at all I think I might do as a. palmer suggest and try to fashion some kind of a gasket to help seal it.

 

[Mad Professor]

I don't know if I'm any good at it or not but if it comes out easy enough it won't hurt to try. I don't think I can't screw it up any worse than it is now. and maybe that's all that it needs. If I can straighten it out any at all I think I might do as a. palmer suggest and try to fashion some kind of a gasket to help seal it.

No need for a gasket if the other parts are sound.

 

[Rx7man]

If your carb doesn't have sloppy throttle shafts, the internal passages are *CLEAN*, and the metering lever height is correct, your carb should would and a new carb is a waste of money. I'm thinking there's an air leak somewhere, and it's most likely in the intake boot.

Good luck with it, it take patience but isn't a complex job.

 

[axlr8]

you should be able to pull that little metal intake ring out and just bolt the carb back on to see if it is causing an air leak like you believe. The metal piece is just a piecce to keep the intake boot from collapsing into the throat of the carb. Let us know what you find.

 

[a. palmer jr.]

No need for a gasket if the other parts are sound.

I've had several older Stihl saws that had the flange of the manifold kinda flattened. I didn't want to put a new boot on them so the gasket worked quite well and stopped a slight air leak. Stihl doesn't put a gasket there because it might cost them an extra dime. No need to fashion a gasket, small engine shops sell them.

 

[bottomcat]

If your carb doesn't have sloppy throttle shafts, the internal passages are *CLEAN*, and the metering lever height is correct, your carb should would and a new carb is a waste of money. I'm thinking there's an air leak somewhere, and it's most likely in the intake boot.

Good luck with it, it take patience but isn't a complex job.

I've put the carb back on but I wouldn't know what to look for to determine if the throttle shafts are sloppy (i'm not even sure I would know what the shafts are. I'm assuming it would be the shaft the throttle linkage attachs to.) the internal passages look clean to me but I'm not sure we're talking about the same passages and I have no idea what the metering level height is, let alone if it is correct. Yeah, I would like to verify someway whether or not the carb is bad before I plunk down cash for another one.

you should be able to pull that little metal intake ring out and just bolt the carb back on to see if it is causing an air leak like you believe. The metal piece is just a piecce to keep the intake boot from collapsing into the throat of the carb. Let us know what you find.

Yes, the intake ring just slid right out. For the life of me I can't figure out why it would be bent outta shape like it is. It's not like it has to be pried out or forced back in. I can't 100% blame it on the guy that worked on it because I don't know for a fact that it wasn't like that when I took it to him. But it sure seems suspicious being as it won't run as good as it did before he got it and he supposedly rebuilt the carb so he would have had it off and surely saw the shape of the intake. And as cheap as that part is I would have thought he would have replaced it. I'll try put the carb back on with the ring to check what happens.

Here are before and after pics. I'm not sure I did much good but it is better than it was. Trouble is now I can't get it to even start like it did yesterday. I removed the spark plug (which I bought new at the beginning of the summer) and wire brushed it. It didn't look too fouled to me and it is getting spark. The only time I can get it to fire at all is by spraying a little ether into the cylinder before reinserting the spark plug (and I did think beforehand, "I hope this is ok to do, maybe I should ask.") I did that a couple of times and it would fire off but immediately die.

 

[Rx7man]

The metering lever is what controls the fuel level in the carb, if it's not set right it won't run properly... By the sounds of it it's not getting enough fuel. which would mean it's either not pumping the fuel, or the metering lever is set too low.. I am in a rush sand can't describe the procedure for that right now, perhaps someone else can take over?

 

[xPosTech]

I wouldn't make a habit of using ether. It has no lubricants in it. Much better to use a few drops of mix under the filter. Or a few drops on the filter.

Ted

 

[HarleyT]

take a screwdriver and remove both covers on the carb and take some pics.