Problems with a 2-cycle trimmer. Any advice?

proud2deviate

proud2deviate

Joined
Apr 5, 2004
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I recently acquired an older 2-cycle trimmer after my father bought a new one. It's no great prize; I had to replace the fuel lines as the were old and rotting. I finally got it running, but not without some effort.

Here's the first problem. I can't get the primer bulb to move any gas. I pump the bulb, and the gas tank gets pressurized with air. There's gas in the intake line, but I can't get any to move through the bulb. To get it started the last time, I had to remove the line from the bulb and squirt the line full of gas with a syringe. It started with minimal effort after that.

Second problem; once started, the trimmer idles too low and will die in short order unless I keep slight, constant pressure on the throttle. It'll do this even after the engine is hot, and it will occasionally cut out briefly even when the throttle is wide open. Bad gas, perhaps?

Any thoughts or advice would be welcome and appreciated. My electric trimmer recently shot craps (Tons of white smoke pouring out of it,) and I can't really afford a replacement right now. The thought of attacking the weeds with a machete doesn't much tickle me, either.
 
Here's the first problem. I can't get the primer bulb to move any gas. I pump the bulb, and the gas tank gets pressurized with air. There's gas in the intake line, but I can't get any to move through the bulb.
Click to expand...
Sounds like the bulb is installed backwards, pumping in the wrong direction?

A general thought: little 2-stroke motors are extremely sensitive to spark plug gap. A thousandth or two either way makes a big difference.
 
Cougar Allen said:
Sounds like the bulb is installed backwards, pumping in the wrong direction?
Click to expand...

That sounds highly possible, but it wouldn't allow fuel to flow into the carb at all even once whetted.

Check the idle adjustment there should be one near the throttle valve.

Get fresh fuel if there is any doubt at all. Make sure it's got the proper oil mixed in.

Tearing it down as far as you feel comfortable and rebuilding is always a good idea.
 
If you had to fill the fuel line manually, then perhaps the fuel filter inside the tank is plugged.
 
First, as stated earlier, fresh fuel and the proper mixture are important.

Also, install a new properly gapped spark plug.

Next.Check the choke, it may be stuck causing too rich mixture then stalling.

Then, try this start procedure .

From a cold start put the choke fully closed(choke on)

Lock the throttle wide open.

Pull the starter.

If you get a response as if about to start then put the choke lever at half.

Pull starter again and if it sounds like it wants to start pull several more times.

If still no go ,close the choke fully and try again.

When it does start, quickly open the choke(choke off) fully and lower the throttle to idle.
 
Okay, update.

The primer bulb seems to be working properly, now. I suppose that when I squirted the line full of gas, it gave it enough suction to do its job. I'm not sure now, however, that I don't have the lines on the bulb switched, as Cougar Allen suggested. I've never had trouble with it before I replaced the fuel lines, so I consider this possible. Is the primer supposed to move gas into the carb via the main fuel line (via suction,) or is it meant to squirt it in directly?


As for the idling problem, I'll give a new spark plug and gas mixture before the next time I mow and see if it improves. I doubt its ever had a fresh plug in probably 12 years of service, so I imagine it's due. After that, I'll try to adjust the idle. I assume it's the large important-looking screw on top.

Then again, after 12 years (didn't realize it was that old, until just now,) if it ever starts again I'll consider it a gift.
 
Check for a crack in the primer bulb itself. It may be hard to see, but the symptoms you listed sounds like a primer bulb crack to me.
 
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