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Stihl HL 100 giving me problems "Help"

6K views 17 replies 7 participants last post by  Modern marvel 
#1 ·
Hi, I'm new here so hello forum. I've got a stihl hl 100 I've been working on and I'm at a loss with it. it runs for a bout a minute and cuts off. I thought it was a fuel issue so a took another unit and switched the carbs out. didn't change anything. then I noticed gas pumping threw the breather tube that was soaking the air filter. so I switched gas tanks with a parts unit and it ran great. well now two days later its doing the same thing. I'm guessing its dying because it's getting to much gas in the intake, but what would cause this? the whole fuel system has been replaced. any help would be much appreciated. Thanks!
 
#2 · (Edited)
You can't just replace parts not knowing what the problem is and expecting it
to somehow fix itself, and I realize that sometimes replacing an entire carburetor
can fix the problem but that's only because you're replacing almost half the fuel system!
Whoever told you to replace that...

Best way to approach these situations, start and take the stuff apart and inspect each piece carefully,
a lot of times $5, $10 fixes your problem.

That having been said, I sure hope you still have your old carburetor.
Don't throw it away, keep it now so if you ever have problems in the future you know you have a good carburetor.

How's the primer bulb?
When those get cracked and corroded they can manifest symptoms such as what you are describing,
in effect the primer bulb on a hand held tool is the carburetor's "fuel bowl" AND float in one unit (except it has no float)
but it is hard to tell sometimes if they leak because the leak can be internal (behind the plate), so as a general
rule if you can't see through the plastic of the bulb I would consider replacing this, a $3 part.

Now if that bulb isn't doing it, then maybe it's your fuel lines.
 
#3 ·
That thing is a tank vent. It's designed to vent in, not out. Meaning NO fuel should be coming out of that tube going into the air filter hsg. The replacement might have been bad also. That's the problem using used parts. The vent is available separately. You don't have to replace the whole tank. Fuel leaking out will definitely affect the running behavior.
 
#4 ·
On an HL100 I have a slightly different problem.

Lately fuel leaks from the tank or lines when it is sitting flat. The tank has no obvious defects.
Then with the tank half full and the fuel filter below the gas level, the primer bulb just makes a squeaking sound when pressed, No gas is brought up. The squeaking sound is inside the tank.

I removed the tank and all lines. All appear to be in tact.

Not sure how to remove the small round white cap carrying 2 lines into the top of the tank. It is hard plastic and not a flexible grommet as with some Stihl saws or trimmers. It has a flat white plastic tab, but firm pressure under that tab won't seem to lift it.

Suggestions welcome.
 
#5 ·
Hi, I'm new here so hello forum. I've got a stihl hl 100 I've been working on and I'm at a loss with it. it runs for a bout a minute and cuts off. I thought it was a fuel issue so a took another unit and switched the carbs out. didn't change anything. then I noticed gas pumping threw the breather tube that was soaking the air filter. so I switched gas tanks with a parts unit and it ran great. well now two days later its doing the same thing. I'm guessing its dying because it's getting to much gas in the intake, but what would cause this? the whole fuel system has been replaced. any help would be much appreciated. Thanks![/

The type of fuel you are using can also cause that problem. if your using low octane pump gas with an ethanol content is just begging for problem after problem with with the entire fuel system as well as other parts. Not to mention the fact that ethanol will attract moisture condensation which is not anything you want running through your fuel system or in your gas tank. If you have already used ethanol gas in your machine with no problems yet, just be prepared for them soon as the diaphragms in the carburetor usually shows the first symptoms. Not saying this is the problem by any means but is something to think about. If available in your area , get a very high octane rated ethanol free fuel and a jaso rated synthetic two cycle oil and be sure to mix correctly. As long as you do that you should not have any fuel related problems out of the normal wear and tear.
 
#9 ·
sounds like a small crack in the fuel line. I would replace those first. the first place the hoses get eat up are inside the tank where they sit in the gas for long periods of time.
 
#10 ·
just because you don't see the crack doesn't mean its not there. cover one end, blow in the other. or use hand held vacuum pump to check for cracks or leaks in hoses.
 
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