Anyone here know how to work on a Homelite string trimmer?

[srvblues00]

I have a Homelite weed whacker that simply refuses to start. Today I took apart the carb and cleaned it, but it didn't make any difference. I also checked the spark plug, but it was fine.. looked normal. I am somewhat famliar with EFI cars, but I don't know hardly anything about carbs! What else can I look for to be the problem? This particular model has an electronic power switch, and it must be in the on position before the thing will run. I had it on run, but still nothing. Is there a small battery somewhere? How does it get a spark? Is there a mini distributor or something?

 

[Bulldozer]

I'm confused. You say the spark plug is fine, but you are asking how it gets spark. Is it sparking or not? Those engines are about as basic as you can get. First make sure you're getting spark, then make sure fuel is making its way into the cylinder.

 

[srvblues00]

<< I'm confused. You say the spark plug is fine, but you are asking how it gets spark. Is it sparking or not? Those engines are about as basic as you can get. First make sure you're getting spark, then make sure fuel is making its way into the cylinder. >>



I removed the plug, and the end of the plugs looks ok. I have not checked to see if it's getting a spark. What is the best way to determine this? I know the cylinder is getting gas because I tried to crank it, then pulled the plug out again, and it was wet with gas.

 

[d33pt]

pull the plug wire and pull start it... you should see a spark from the wire onto a piece of grounded metal... make sure it is getting air, fuel, and spark.. it should start then

 

[Squisher]

Take off plug wire, put screwdriver into plug end of wire and hold the screwdriver shaft close to the plug without touching it and pull starter cord. It might take two people to do all this.

It gets the spark from a magneto(a kinda generator)

 

[Squisher]

Reasons for not starting if no spark: bad switch, bad spark plug/wire, bad magneto.

Reasons for not sarting if spark is good: carb clogged, stale gas, spark arrestor clogged(screen in the muffler), no compression.

 

[rgwalt]

<< spark arrestor clogged >>



Had the same thing happen to a trimmer. Definite check this. It is located where the exhaust comes out.

Ryan

 

[bunker]

How long has the gas been in there? You could always try a shot of ether into the air intake. That's what I did for my lawn mower today because I seem to have forgotten to winterize it and dump the gas last fall...oops.

 

[Bulldozer]

The tests mentioned above do not test the spark plug they only test the electrical system. Remove the spark plug from the head and then reattach it to the plug wire. Set or hold the threaded part of the plug so that it contacts the cylinder or other conducting surface (metal). Pull the starter cord and see if you see a spark jump in the gap. Make sure the switch is in the on position. This tests the plug and the electrical system at the same time. If you get no spark, try the tests mentioned above. If those tests work, replace the plug and start wackin' weeds. If those tests fail you have an electrical problem elsewhere (bad wire, magneto, or switch).

 

[Bulldozer]

Another thing to check if you are getting spark and it isn't starting is the fuel. Make sure you have a proper fuel/oil mixture.

 

[Squisher]

Also, is the choke closing the butterfly in the carb? Did it ever even sputter at all?

 

[Moonbeam]

I tried working on one once, but I kept falling off.

 

[srvblues00]

I pulled the plug out, put the boot back on, and there's definatley a spark. It's dark outside now, so that made that part easy. I'm about certain it's getting gas, the cylinder and piston look wet and smells of gas, and so does the plug. I have pretty much concluded that it's the fuel or something in the muffler. The fuel has been in there since last fall, so that may be what's causing it. I would think it would still start, tho, but I guess maybe that gas/oil mixed stuff might be a little more sensitive to time. Choke has 3 positions.. closed, half open, and wide open. I've cranked it many times in all 3 positions. Sounds pretty much the same, and I get no response from any of the 3 positions. I have checked, and the throttle is WOT when I hold the lever at WOT, so there shouldn't be an issue there. I'm pretty sure I'm getting compression - there's a big difference when pulling the string with the plug in and out. There's prettty decent resistence with the plug in. It has never sputtered a bit, absolutely nothing. Tomorrow I'll look into the spark arestor.

Thanks for the replies! Hopefully I can get this beast running tomorrow

 

[Squisher]

Take that spark plug out and clean and dry it. Try to pour all the gas in the cylinder out and leave the plug out for a couple of hours to let the combustion chamber dry(if you have some compressed air to shoot in there this would only take a minute). Pour out all the old gas including what is in the priming bulb(by pushing it repeatedly).

You can clean and dry that spark arrestor, but a new one is only $2.

When you go to start it only prime it two or three times.
Put the thing on full choke and pull until you get some sputtering.
Once you get a sputter set that choke back to the middle position and start it.

 

[jsbush]

I've got a problem I never fixed on my trimmer.

It won't start unless I pour a little gas in the cylinder then put the spark plug back on. It's like the fuel doesn't reach the cylinder, but once I get it started by putting a little gas in the cylinder first, it works fine for hours.


Any ideas?

 

[Bulldozer]

jsbush:

Have you cleaned the carburetor? Has the trimmer seen heavy use? If it's been used heavily and the piston ring is worn out, lowering it's compression, it will make it difficult to start. Proper fuel/oil mixture is usually helpful, so that the plug isn't fouled. I use amsoil synthetic that is designed to be mixed at 100:1 on things like trimmers. They always start easily and they don't foul plugs. Also make sure the plug is properly gapped and the air filter is clean.

One of my snowmobiles takes a good 200 pulls to get started. It has over 4000 miles on it so I believe the piston rings are just worn out. In this case it doesn't seem to develop enough compression to get the combustion process started. I think that after a couple hundred pulls it must be getting warm enough to seal better and start to fire. Let me tell you it's not fun pulling over a 570cc twin 200 times. I'll probably get around to changing the rings this summer.

 

[Squisher]

jsbush, what Bulldozer said plus maybe your priming bulb maybe cracked and not sealing very well.

 

[schmedy]

Sounds like what the problem was since you had to pour gas in the carb was that you didn't buy fuel stabilizer in the fall when you put it up and now the gas turned to lacquer. Even if you can get it started you should still either take the carb off and clean the bowls and jets or take it to a small engine shop and have them do it (all of 10 bucks). I know when I lived in CA this was something I never thought to do since all the gas powered stuff was used almost year round, but now I'm in VT so we do have seasons here and put things up.

 

[Ornery]

"Pull the starter cord and see if you see a spark jump in the gap. Make sure the switch is in the on position."

Just buy a new plug! It's less than two bucks for crying out loud!

I had a mower that wouldn't start. Pulled the plug and tested as above. Sparked just fine, so I went on to checking other things. Finally put an inductive timing light on the wire to see if it was working. It wasn't! When I pulled the plug out and checked with the timing light, it worked, but under compression, it wouldn't. A new plug did the trick. You have fuel, so that isn't the problem. You have spark outside the combustion chamber, so the ignition is good. Even if it isn't the plug, you're only risking two bucks!

 

[JohnCU]

<< Even if it isn't the plug, you're only risking two bucks! >>


Yeah, but that's two twenty-minute phone calls (and only seven cents a minute after that).

 

[Ornery]

LOL. Man, I just think of that mug and it makes me laugh!