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I bought this old leaf blower for $35 on craigslist because I wanted something cheap that could vacuum and chop up leaves. It ran well at the time, except one of the exhaust bolts was stripped. Well it turns out it was the engine block that was stripped, not the bolt. But I was eventually able to get the hole re-tapped and use bigger bolts to get it on there. So I finally had the thing running well. Then, as soon as I got it running well, suddenly it wouldn't start at all.



So I pulled the cord till my arm fell off, but it would not run. It was running perfectly, then suddenly not at all, so it doesn't sound like it would be a dirty carb (but who knows). To me it sounded like a fuel line issue. When I took the cover off and pumped the primer, it didn't pull up much gas. So I figured its either the bulb or the lines, might as well do both. I did them today and it sure looked like the lines. The in-tank filter had fallen off and the lines in the tank looked like they had crumbled a bit. So after fighting with this thing for a couple of hours, I was able to replace both fuel lines and the primer bulb. But alas, no change in starting.

And lets back up a bit... I WAS able to get it started before off of starting fluid. But once it ran out, it would sputter and die. All the more reason it seemed like it was old rotted fuel lines not sucking up the gas.

Did I mention it was a 1998 model blower?

Well today, I couldn't get it to run at all. Not off gas and not off starter fluid. I actually thought I was going to be successful with this project, but nope.
So any thoughts on what might be going on with this thing?

Here is a picture of the carb before I took the lines off. Can you tell which is the fuel line and which is the return line? I thought the fatter one was fuel, and it sure looked like that was the one previously attached to the in-tank filter. But when I primed it, I could see air bubbles going down that line, into the tank. After a while, I finally gave up. I'd think even if I had them on backwards, it would still probably work, it would just be sucking in un-filtered gas? But just to be safe, I switched the lines. No difference with the lines switched. I am officially stumped.

Walbro have an excellent web site, go there and read yourself rich.
Regardless of the brand, they all work the same way.
The carb will not work if hooked up backwards unless you made the return line go deep into the tank.
And the thick line is the return, the thin is the supply and it has to be heavy walled tube or it will collapse under the influence of the fuel pump.
The carb has an internal filter which from what you have said will most likely clogged

May not hurt to pull the plug out and shine a light into the cylinder and look around Especially check around the port for the exhaust for scoring and other damage. Broken fuel lines and clogged filters can cause lean running leading to cylinder damage.

Ok I poked around with this a little more today. I wanted to fully clean the carb first. But this little cube carb is nothing like the lawnmower carbs i've worked on. This was as much as I could break it down. It looks pretty clean actually. Any tips on how to clean this?



Moving on, I was really concerned that it seemed I had stripped the threads in the engine block, where the carb attached. That's what happened to the exhaust and I was able to get it retapped, but I also had to drill out the holes in the muffler a bit. This didn't seem like something that would work for the carb though. When I took it apart today, I discovered that the carb screws into this plastic bracket, and that bracket screws into the block! That's great, because now I just need to replace this plastic piece and I should be good to go!!

Well except for one little problem. This thing is from 1998 and that part is discontinued EVERYWHERE. There may be one on ebay, I'm waiting to hear back from the seller to see if he can post pictures you can actually see. But beyond that, I may be out of luck. I hope I can get this part, this blower ran really well WHEN it would run!

As said previously, read the Walbro service manual, it is as good as you can get.
The tiniest bit of crud under the pump diaphragm and it won't pump and we are talking barely visible crud.
Cube carbs are simple to work on but because of all of the very fine holes can be a bugger to clean as most of them are blind and blanked off.

bertsmobile1 said:

As said previously, read the Walbro service manual, it is as good as you can get.
The tiniest bit of crud under the pump diaphragm and it won't pump and we are talking barely visible crud.
Cube carbs are simple to work on but because of all of the very fine holes can be a bugger to clean as most of them are blind and blanked off.

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Do you have a link to the service manual you are referring to? I'm on their site and I'm not finding anything but new carbs I can buy. Nothing about servicing 20 year old ones. Unless I'm looking in the wrong spot?

You have not mentioned the existence of a spark.(unless I missed it somewhere..)
Is there spark?
Also, check that the muffler is not plugged with carbon.........
Try pulling the starter cord with the muffler off using starting fluid.

That model, I believe, has the flywheel key cast into the flywheel.
It is soft and easily sheared.
Give it a look.
FWIW

l008com said:

Do you have a link to the service manual you are referring to? I'm on their site and I'm not finding anything but new carbs I can buy. Nothing about servicing 20 year old ones. Unless I'm looking in the wrong spot?

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From the main page , Walbro.com click on the words "Parts & Service" in the top navigation bar.
From the Parts & Service page (walbro.com/parts-services) go to the bottom of the page and there is an embeded video called "Walbro Carburetor Service Video" watch it then to the right corner you will see 3 boxes.
Click on the one that says "SERVICE MANUALS"
Download the HDA or WA which will be the most similar to your carb but they all work the same

As the machine will no longer fire using starting fluid, I have to wonder if the carb is not the issue....but that's just me..

Ronno6 said:

As the machine will no longer fire using starting fluid, I have to wonder if the carb is not the issue....but that's just me..

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Well it's definitely *AN* issues now, as the plastic adapter plate is stripped so I can no longer bolt it on nice and flush to the unit. Once I get that piece replaced and the carb put back together, then I can go from there.

On your unit the line closest to the primer bulb is the return line. To clean the walbro, just shoot carb cleaner through every hole you see on it, but be careful with the little brass fittings they are valves, and sometimes carb cleaner will soften the rubber flaps in them and make them stick. So sometimes I will give a little shot of WD40 though those instead. Sometimes the bulb at the end of the pick-up tube in the tank gets gummed up, so I'll shoot a little carb cleaner through that too, and blow out with compressed air. Also, before you unscrew the high and low adjustment screws, turn the in all the way gently first, and count how many turns out they are, so you have your initial settings.
When people talk about cleaning the muffler, it's usually just the screen you have to worry about, and you should be able to access that without pulling of the whole thing. on some units you just pull one screw by the "tailpipe", and slide the screen out to clean, on others you pull 2 or 3 screws, and pull off a little cap over the screen, and lift it out.
The fuel lines crumbling in the tank is due to ethanol in the fuel. I cannot say enough about the evils of ethanol when it comes to 2 cycle engines. If you can't find non ethanol fuel, at least get some Sta-Bil fuel stabilizer and add it to your fuel can. Get the 360 marine kind, that protects against ethanol damage.

Ronno6 said:

As the machine will no longer fire using starting fluid, I have to wonder if the carb is not the issue....but that's just me..

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Very true.
You would not believe just how many come into the shop with a messed up carb where the owner has tried to fix a tank vent problem by pulling the carb apart then spraying carb cleaner on all the vitton bits ( which carb cleaner destroys ) scratched up diaphragm fave where they have scraped it with a razor and a blown ,metering diaphragm from blowing out the holes with 150 PSI of unfiltered air.

There was just ONE carb adapter plate on earth left. It was on ebay, and i got it. Stupid thing needs a gasket. Another week, another $9. The gasket on the old plate was very thin and totally disintegrated when i tried to remove it. The saga continues.

And there is a good reason why there was only one left so be careful with yours

1008com, any chance you can take the adapter plate to a fab shop and have them make you another, just in case?
To

Gaskets come apart pretty often on carbs. I buy gasket paper by the roll, and assorted sheets, as I am making one every couple days. I will scrape off the old one as carefully as I can, so I can trace them onto the gasket paper, cut them out with scissors, then use various punches to form the holes. Often I will make two, and keep one as a template.
Since you said the original disintegrated, maybe one of the others, like from the other side of the plate, or the other side of the carb, can be used as a basic template.

zman111666 said:

Gaskets come apart pretty often on carbs. I buy gasket paper by the roll, and assorted sheets, as I am making one every couple days. I will scrape off the old one as carefully as I can, so I can trace them onto the gasket paper, cut them out with scissors, then use various punches to form the holes. Often I will make two, and keep one as a template.
Since you said the original disintegrated, maybe one of the others, like from the other side of the plate, or the other side of the carb, can be used as a basic template.

Click to expand...

I just bought a full gasket kit for this engine on ebay. The carb adapter plate is impossible to get but the gasket kits are still readily available. This way I can put all new gaskets in and hopefully be done with this unit and simply use it. Fall is almost upon us after all!

New fuel lines, new gaskets, new adapter plate, cleaned up carb. I'm SO CLOSE i can feel it! I'm just having one last problem!!

For the life of me, I cannot find a way to hook up the throttle cable that lets you get the full range of the throttle lever through the full range of the carb. I either get half the range of the throttle lever (between idle and WOT on the carb), or the linkage is in there at such an odd angle that it binds up and I get even less. I'm stumped, I've been messing with this link for the past hour and a half!

Here's a picture. The carb is not installed but when it is, the bolt follows the blue line, just to give an idea of where it is normally situated. The orange line connects the holes where the link is supposed to connect. I feel like there's some 'trick' to this that I am missing. I mean how many possible ways can there be to install this thing. Basically between 4 and 8. And I'm pretty sure I've tried them all. *SHRUG*

Welp i made a short video of the link installed the way it's oriented in the photo above, so you can see how limited the movement of the lever is, but I'm only on cellular internet right now so I can't upload it.
But even though the movement of the lever is severely limited, it does seem to be moving the butterfly in the carb fully, so I put it together like that. I figured F-it. I've spent WAY too much time on this p.o.s. Well after just about pulling my arm off, the damn thing started! Who would have thought! The plug looks a little old, I wonder if it would run even better with a fresh one. But I did get it to start and run NOT off starter fluid, off it's own gas! I only ran it for a minute or so because it was 10PM and I have neighbors. But this weekend I'm going to mow, and afterwards I'll use this thing to clean up and we'll see how it goes. Hopefully with all the work I put into this thing, I get at least a few years out of it. Even though it's already 20 years old, it's practically brand new now

I'll still post the video later tonight when I get home.

Here is the video of the lever and carb movement.

Sure you have got the carb right way round?
the hole for the impulse feed usually goes against the engine

Yup pretty sure. If I flipped it any other way, the fuel lines or the bulb would be on the wrong side. Plus it did start so it can't be THAT wrong

I used the blower a little more today and here's how it goes.....

So it starts pretty easy now all things considered.

The choke lever is WAY too lose but thats because I clearly reassembled wrong, theres probably a bushing on that lever i left out, I need to work on that.

It runs but only at 1/3 or 1/2 throttle (hard to gauge based on the weirdness of the throttle lever).
If I give it more gas than that, it instantly bogs down and dies. Then it starts up again, fairly easily.

When you give it the half throttle, it generally runs really well. But then occasionally it will start to bog down, but usually works through it and goes back to running well. Sometimes ill knock it down to 'idle' then put it back up to halfish throttle.


I'm thinking all this means its not getting enough fuel?
If that's the case, I know it's not the lines, and I know its not a leaky gasket as they're all new. If theres a fuel shortage, it would have to be either still some dirt deep in the carb, OR, maybe that goofy fuel filter that's in the tank is not letting enough fuel through? I suppose the last one is easy enough to test, just pop it off and see how it runs. I'll probably try that next time I'm out of gas.

Could it be a spark plug related problem? It doesn't sound like it to me but I'm no expert here.

Sounds like fuel starvation tome.....

Well I tried to use this thing again today and it was back to it's old behavior, running for a few seconds at best then conking out no matter what I do. I was hoping if it could run, even poorly, I could use tons of seafoam to clean out the inside of the carb but no luck.

I also removed the fuel filter and put in a new spark plug but no change in behavior.


So now my options are:

1. Give up
2. Buy a new Carb
3. Clean this carb thoroughly

At this point I'm tempted NOT to give up since I've replaced almost everything so far.

A new carb is $36. I've spend enough on this stupid thing but at this point, it does seem wise to do this. Too bad they're not $13 like the new carb I got for my honda mower. At that price I'd just get it and be done :/

I've cleaned the carb as best I can, and unfortunately that's not good enough. I'll have to look in to this more.

Seems as though I think you said that originally the fuel line was broken in the tank, so the carb could have sucked up all sorts of stuff, including tiny bits of rotten fuel line. That stuff could be really hard to get out. Another thing about the carbs is sometimes the little rubber valves under the brass fittings (I think Bert referred to them as "viton") can get stuck, and you have to be delicate to free them up. You can check them by holding the end of a new spare fuel line to them, and blowing/sucking to check it's operation. You should be able to blow, but not suck.
One other thing I don't know if you checked is the exhaust port. Usually it's just the screen that gets plugged up with carbon, but occasionally carbon will build up in the exhaust port all the way up against the piston, to the point of almost closing up the port entirely. When that happens, it does like you mentioned, starts up but dies almost immediately. So definitely make sure all parts of your exhaust are clear.
One last thing to mention is the filter in the tank at the end of the fuel line. Make sure you can blow through that relatively easy, or clean/change that as well.
I probably repeated some stuff that was already said, but i know how frustrating it is when you think you covered all bases, and it still misbehaves.

I bought a new $36 carb on ebay for this thing, bolted it up, and now here's where I stand. Once this thing is running, it runs perfectly! Like it's brand new! But getting it to start takes about a thousand pulls. I have to just about pull my arm off to get it started. Its as if the primer bulb isn't priming. But how could that be, isn't that also the same pickup the engine uses while running? So if the primer was getting no gas, wouldn't the engine not run at all?

Also this design uses a goof button that itself pushing the primer, you can't push it or see it directly, so I can't tell you exactly what's going on with it. And the same bolts that remove the plastic shell over it, are also what hold the thing on in the first place.

Any thoughts on this? I'm so close, if I can just get it to start easier, i'll be golden. I did use it to do some blowing and some vac'ing friday and once it was running, it really worked great!