Automatic Choke?

[tower50]

Greetings Everyone,

On my 2010 Symba, last fall before storage I drained the gas tank and ran the carb dry. I've gotten it out, put fresh gas in it and I can not get it to run right, very surprising since it ran fine last fall.

Seems to be running rich and won't idle, dies as soon as you let of the throttle.

It almost seems like a stuck float or a stuck choke.

What kind of choke is on the 110? I don't know, there's black component on the top left side of the carb but the the service manual doesn't address what it is. Some kind of an electric choke?

Anyone have an idea, cause I'm fresh out.

2010 Sym 110,

[scoobynut]

I'm pretty sure they are auto-choke as I haven't seen any provision for a manual choke or read about one in the owner's manual.

I didn't drain my tank last winter like you did, just filled it up and put some fuel stabilizer in.  The bike sat for over six months and when I went to start it, like yours it didn't run very well, wouldn't hold an idle and was sputtering a lot.  There is a thread in here about starting your Symba after the long winter, and I read where that guy drained the carb and added some sea-foam or carb cleaner to the tank to clean the crud out.  I followed his procedure and mine is running normally now (Do a search, you should find the thread in here).  Anyways, after trying to get the bike to run right for several days, I was finally able to ride it, even though it wasn't running very well.  I also drained all the old gas out and filled it with fresh stuff, adding a few ounces of Sea-Foam every time I filled the tank.  All kinds of moisture was shooting out of the muffler, I figured condensation from sitting so long.  It seems like the Sea-Foam will remove the moisture, and I believe it did.  Anyways, after all that rigamarole, the bike starts and runs great now.  Try running through a few tanks of gas with a few ounces of the magical Sea-foam in each one, it should help.

[tower50]

Thanks for that reply. I've got a can of Sea Foam in the garage, but I figured starting the season with a clean tank and a dry carb shouldn't be a problem.

I'll put some in the gas tomorrow.

The choke still intrigues me though, not manual or electrical? It's a kind I'm not familiar with, unless it's like the old style in some cars where hot air comes up from a tube from around the exhaust manifold and as it warmed up the heat from the tube opened the choke plate all the way.

But I can't imagine that, I haven't seen something that old fashioned in 30 years or more, and if memory serves, that wasn't a very good system anyway, the tube to the choke was always getting clogged with crap from the exhaust.

Worst come to worst, I'll pull the carb and go through it, then I'll find out what is up with the choke.

Another thing: on page 3-4 of the service manual there is a part called a"auto by-starter coupler" what's that?

                                                   Cheers

[Morgan]

Symbas don't have a choke, they have a by-starter. Chokes operate by reducing or "choking" off the air, which richens the mixture to the engine. A by-starter adds more fuel, which also richens the mixture. Two different methods, same result: more fuel in ratio to air getting to the engine.

An auto by-starter uses either a heat sensitive piece of metal (similar to the exhaust heat tube you mentioned) that allows more fuel in when it's cold, and then as the engine heats up it cuts off the extra fuel... or, as I believe is the case on the Symba, an electronic sensor is used to accomplish the same thing. Probably more consistant and reliable that way.

The "auto by-starter coupler" in the image mentioned is just the electrical connector so it can be unplugged/removed. They don't seem to point out the by-starter itself. I'll have to dig into my Symba a bit more and see if I can identify it.

-Morgan

[Morgan]

Hmm... after looking into it a bit more, it seems that it's more low-tech than I thought. No electronic heat sensor is involved on the Symba. There's just a heat sensitive metal spring. After the bike it started, power from the AC generator goes through an electric heater element and slowly warms up the spring, causing it to cut off the extra fuel supply. This is all completely independent of how warm the engine actually is... though I suppose ambient air temperature would affect it a bit.

-Morgan

[Morgan]

After even more reading (not easy to find much info, though) turns out it's not actually the spring that expands with heat, but rather liquid wax. Talk about old-school.

The bystarter is a small, black cylindrical device with two wires coming out of it. When the engine is running, 12V are applied to these wires. Over about 10 minutes or so, the bystarter warms up as the engine warms up. There is some wax in the bystarter that is heated by a small heater. It expands, and extends the bystarter needle about 1/8".

-Morgan