Ryobi Blower Only Runs With Choke Closed

Spaying carb cleaner in or around a still assembled carb is pretty much a waste of time unless the only problem is sticking linkage. And my 30 year old chain saw is on it's 2nd plug. Plug's don't go "bad" all that easily. Plugs do get dirty if you use too much oil but a few swipes with a wire brush is usually all that is needed. If the electrode is not visibly worn then the plug can be cleaned and reused. But I won't argue that these motors are not for everyone.

You have a carb problem. Debris or water has gotten into it. Something is clogged or stuck.

Your basic problem is the mixture of fuel to air ratio. There are many things that cause this condition. To fix the problem you must do all of the following:

Make sure all screws are tight that hold the carb, crank, and any other screw that may allow air into the cylinder.

Make sure the gas tank vent is working properly.

Replace the fuel lines and make sure the fuel filter is attached. They become brittle, they are cheap. Hint: when replacing the fuel lines, cut at an angle. This will allow it to pass thru the holes much easier. Buy the correct size.

Replace the plug. I know you said it was new, but trust me on this. Plugs can become useless if too much gas gets on them, therefore not allowing the full electric charge to produce the spark required. Also, even new plugs can be bad.

After doing ALL the above, you can try to start it. If you have the same problem, you must dis-assemble the carb and blow out all the passages. There are only a few parts. Take pictures at each step if you don't feel confident. Reassemble. Take plug out and check for spark to make sure you didn't "gas foul" the one you just put in.

That should do it.

Hank

Yeah, I agree there (well, apart from the stray apostrophe ;)

The main issue I think is that it doesn't take much for them to go from working to dead - bigger IC engines tend to degrade gradually, but the smaller ones can work one day and be utterly dead the next.

I agree that's the most likely. It still sounds odd that there's no gasket between carb and engine.

Oh, one thing I heard recently was that some Ryobi engines have just a plastic crankcase cover, and the screws that hold it down work loose - it's the crankcase pressure which drives the carb's fuel pump, so once the crankcase seal goes bad the pump in the carb stops operating properly. Not necessarily relevant in this case, but it's something to keep in mind when working on the small Ryobi stuff.

cheers

Jules

Yes, pictures are useful... on the small carbs I've seen, some of the parts can fit in more than one location/orientation, so it can be useful to take pictures (or, if you don't like getting your camera dirty, do what I do and scribble down notes and diagrams on a scrap of paper. And try not to lose the paper ;)

cheers

Jules

I think some of them even have plastic crankcases these days. I heard once that honda has used carbon fiber pistons in some racing engines. Composites have come a long way.

Loose bolts just about anywhere are a problem for 2 strokes as they have sealed crankcases and rely on that to transfer the fuel/oil from the carb to the crankcase then into the combustion chanber. I had one that the cylinder to crankcase bolts had loosened. In any case problems vary and engines can deteriorate or die in one shot. Depends on the problem. Fuel issues are common in these smaller engines because people don't use stabilizer or continue to use gas that is too old even if it had stabilizer in it. And the fuel gets contaminanted easily because it is poured form container to container or left open to absorb water.

There's really two schools of thought here. Buy something of moderate quality and plan on occasionally fixing a minor problem because it's the last one you will buy for 30 years. Or buy a low end 2 stroke or an electric one and just throw it away when it develops problems. If you cant' fix it yourself the second path is probably the recommended way to go as taking anything to the shop these days will easily result in a bill that is a sizable fraction of the original price. Unless you're in the commercial end of the business, plan on using it for many hours daily, and paying maintenance is factored into your use. Then you want to buy top of the line quality.

re: "...taking anything to the shop these days will easily result in a bill that is a sizable fraction of the original price."

Especially when I only paid $55 on Craigslist for the blower!

Either I'm fixing this thing or it's back to Craigslist for another one.

re: "It still sounds odd that there's no gasket between carb and engine. "

I just looked at the on-line parts list for the 340BV and there is indeed a gasket on the backside of the carb.

Then there's a heat shield, then another gasket, then a carb spacer then another gasket then a baffle assembly then another gasket and

Jeez!

When the screws that hold the plastic crankcase cover become loose, it sucks in air when the piston is on the up-stroke. This will result in a lean mixture and usually too lean to run (same symtoms as a dirty carb or not getting gas). If you richen the mixture with full choke or spray starting fluid in it , it may fire.

I mentioned tightening all screws in my last post.

Hank

An update:

I wanted to blow the maple-copters off of the driveway and onto the lawn so I could mow them up, so I figured whatever air I could get out at full choke was better than nothing.

I found that if I feathered the 3 position choke lever I could get a lot more power by holding it between the "fully closed" and "partial" detents. If I let it drop into the "partial" detent it would stall - at least at the beginning.

After about 10 minutes of run time, I found I could actually run it at the partial setting for a few minutes before it would begin to labor. If I moved the lever back towards fully closed, it would pick up speed and I'd go through cycle again.

I wonder if it's slowly cleaning itself out.