OutdoorKing Repair Forum Forums Repairs and Maintenance Questions On Hand Held Blowers/Vacuums Petrol Blowers & Vac's Ryobi 2-stroke Blower

Hi All,

I picked up a 2-stroke ryobi blower today, for $15 from the tip.

Looked pretty good, so I thought I would give it a go, first step was to replace the Primer bulb, now it has an issue I just can't put my finger on.

It will start, sometimes with the primer, sometimes without, it idles well, and if you leave it on the ground, it will rev well.

If you pick it up, it will die out when you open the throttle, it just makes this sort of 'throaty' sound, then goes out, occasionally, if you hit the primer a few extra times, it will take longer to die, but unlike other fuel issues I have seen with these, if you so much as touch the primer while it's running, it dies straight away.

Usually, if it is having trouble getting fuel, I find hitting the primer while it is going keeps it running till you stop supplementing the fuel.

Once it dies, it is very easy to re-start without priming, but it just dies again soon after.

Once a little warm, it will only idle in any position, even on the ground, opening the throttle you just a little gives you the throaty sound, then death.

A little more, I just went out to take a few pictures, and noticed although it was off, fuel was dripping from the air filter.

Perhas the metering diaphram?

I have removed the fuel filter to dry for now, and I will see if I cant work out the issue, if anyone has some advice, please let me know, I'm still fairly new to these engines, and will happily take any halp I can get.

Here's the pics:

Because it won't tolerate any extra fuel when it is running, it sounds as if it is rich. Fuel dripping from the air filter sounds like flooding or over-priming. The most common cause of flooding with those diaphragm carburetors is an incorrect lever arm setting. However there is another possibility as well as that: you said you had worked on the primer bulb. If you happened to connect the input and output tubes the wrong way around, you might get a result something like you've described.

OK, so I have been fiddleing about:

I swapped the lines on the primer, no more pouring fuel, but still not going past idle (at all now) then i went to adjust the carby, only to find it was non-adjustable, so I took it off to get a look, dropped it, and broke the fuel inlet.

Swapped the fuel pump and inlet from a walbro copy (perfect fit, looked identical in all regards, bar material) and popped it all back together.

Now it wont start at all, and the primmer is very hard to push, does the primer pump fuel into the carby, or put pressure in the tank?

UPDATE:

OK, now it runs, idles well again, and rev's up a little, but full revs still kill it, and it does not really like being picked up.

I think it may well be running rich, but I can't find any adjustments on the carby, how else would one adjust a rich mix?

Could this also be too much oil in the fuel, I may have popped a bit to much in.

OK fixed the fuel mix up, ran a little better, idled it for 10 minutes, got a little bit of power, the the throat sound, and dead.

Let it cool for 40 min, now nothing, it almost went after about 50 pulls, but now my fingers are red, bruised and very sore, and i think ive pulled some muscles in my arm between that and my attempts on the weed-eater.

must have pulled over 200 unsuccessful pulls today, next time i should do some warm up exercises first!!

Mr Davis,

Have you tried to run the blower without the muffler to see if you get full rpm's?

Gave it a go Bruce, but no difference, and the muffler seems good to me on inspection.

it tastes awful though...

Ty, is the plug wet, and is there surplus fuel in the cylinder/crankcase? Have you tested the ignition? If the answers are yes to both questions, the carburetor is at fault and that is what I will focus on below.

I think the primer-equipped Walbro pumps air into the fuel tank, so if you connect it backwards, it pumps fuel into the pulse chamber of the carburetor instead, which floods it. (Not sure about all that, have only read up on choke type, not primer type, in detail, but I read a short treatise on the perils of connecting the primer backwards on another site.) So, check that your primer is pumping air into the fuel tank, not fuel into the fuel pump chamber.

Have you checked the metering lever setting? That is fairly sensitive, and affects the mixture. The emissions carburetors appear to have an internal adjustable needle valve as well, which acts as a coarse mixture adjustment. Finally, the fuel pump pop-off pressure also has a strong effect on the mixture:
http://www.aerocorsair.com/id28.htm

On a carburetor with no external mixture adjustment, once it has become seriously fouled up, the only solution seems to be to go through the carburetor manual and adjust everything by the book. What model carburetor is it? The full manual is available as a free download for most of them.

I'll check the plug again tomorrow, it did not seem wet earlier.

I'm thinking I need to experiment a little with the carby, and try and get a result, everything else with the machine seems to be fine, so I guess that's the way to go.

The article you mentioned seems to be helpful, it mentions overheating, and now that I think about it, it did heat up very fast for a machine that was only idling.

As you know, Ty, I personally favour the "comparison carburetor" process. I take it that in your extensive supply of light engines you would have another Ryobi engine the same as this one. Why not test one of them to verify it is running properly, then try a carburetor swap to the problem one and see how it behaves? It would be irritating to go through all this and then find it is something dumb like a crankcase leak.

That's why I'm having unusual difficulty with this one, while I'm still fairly new to the smaller engines, I tend to get by quite well simply diagnosing issues by swapping known good parts.

However this particular engine is a little different to anything I have, more-so is the carby.

I have a box of about 40 Walbro, Zama and Other mini carbys, however the particular layout and connection of this carburetor makes it impossible to hook up any of the others I have here.

The throttle cable is not the usual hook, or bullet tip, it is a bare end cable that screws in, which brings the number of suitable carbys here down to 3, of those, two cannot be connected as the position of the throttle cable, and the surrounding mounts mean the carby wont fit, or operate, and the third of those is faulty, and wont sit right either way.

Thanks Ty, that explains why you haven't just done a diagnostic swap of carburetors. I take it the carburetor is of an unknown brand? Otherwise you'd have quoted the type and we'd have been out looking for an overhaul manual for it. If it is a mystery carburetor, it takes a lot more familiarity with those little guys than I have, to work it out from first principles. There are several possible designs for most aspects of them.

Well, you got me thinking Grumpy, I have made a few mods to the air filter, and managed to fit a nice Zama, and now she seems to be running really well.

I will need to change the throttle control cable, to suit the new carby, but that should be easy enough.

The original was a Walbro, but I cant find the numbers yet, I'll have a look tonight, under a good light.

My only thought it, will the change in carby possibly mean a change in fuel/oil mix?

No, the oil is only there to protect the piston rings/bore, and the main and big-end bearings. So long as it manages to get through the main jet, it's all good. Since it runs properly with the Zama, the fuel is getting through, and it can't get through without taking the oil with it, or there would soon be a pool of oil over the jet, which would stop the music. So, same petrol/oil ratio regardless of carburetor.

If you need a challenge you could identify the Walbro model, study the manual, and do some experiments Ty. Since meanwhile you'll have the blower working, it wouldn't need to be a high priority project. You might even do the future tests with the Walbro on a different engine, rather than disturb one you may be using for serious purposes. My system is to keep no spare parts, just a spare machine in working order, and then never use the spare machine so it doesn't end up half as bad as the bad one you are testing after a couple of years. That means having now found it's the carburetor, I'd either choose a permanent replacement carburetor and throw the bad one away, or I'd laboriously fix the bad one. Frankly, since the bad one is an emissions carburetor and therefore a pain in the backside to tune, it would be in the skip already.

The old one will just join the Walbro shelf of the micro carbys box, I tend to keep a fair stock of spares as I have so many machines passing in and out.

Ill have to get some pictures up of the current set-up, it's a little funny looking as I had to use the throttle control off a mower, due to the restrictions of the space.

The only area I could put the cable through required the cable to extend to increase throttle, while trigger type setups usually retract to bring the rev's up!

The blower has a universal 4-stroke mower throttle control, and a cable looping to the back!

As I've said before, Ty, I can see some advantages in the ability to run a fixed throttle setting with those very small engines. However if you prefer the trigger system, I'm fairly confident one could be put together, probably by just soldering a different cable-inner end fitting onto an existing throttle cable. That used to be a routine maintenance operation in the "good" old days.

I will eventually update the cable, as this machine has a slide lock that lets you lock the trigger at any point, but for now it should be fine.

The main issue won't be the cable tip, it will be reversing the operation direction of the trigger, as I need it to extend at the carby end for accelerate, right now it retracts.

It's not a huge issue just yet though, this is not part of the collection, just a blower for the deck, so originality is not a concern, and it's working well currently, so I might refrain from fixing it till I have nothing else to do!

Your premix ratio will effect the mixtures.

The symptoms sounded to me like you could have had the wrong ratio fuel in it.



I think i have a blower here the same as that one.
Might have to fix it one day.

I thought that myself at one point, but I re-mixed fresh fuel at the exact 50:1 Mix required.

Either way it's going strong now!

Once I get my camera back up and running, I'll get the photo's up of my weird throttle set up.

It's gone as of 10 minutes ago, I mounted a small bracket behind the carburetor, to move the throttle cable to the intake side, now then the trigger pulls, the cable pulls the throttle open, before this, the only set up I could get running was to mount the cable from the filter side, and therefore it had to be a stiff cable so that it could push the lever towards the cylinder, and as the trigger control pulled to accelerate, i had to mount a throttle lever that pushed to accelerate.

Now with the bracket on the cylinder side, the trigger (original) pulls the cable, which pulls the lever toward the bracket on the cylinder side, opening up the throttle.

As the bracket hides under a shield, it does not stand out as a modification and the whole unit looks quite original, all i need to do now is mount a new air filter (as the old one has holes on the side that allowed the stiff cable through) and remove the old starting instruction label (which has instructions that no longer match the machine) and it would take a well trained eye to spot anything on the machine is not original.

I'll swap the filter, and get some photo's up of the new, and weird set up.

OK, Here's the crazy set up I had for a bit, all gone now, back to proper original trigger!