Troy Bilt 2-Cycle String Trimmer Won't Start

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  #1  
Old 04-14-12, 04:00 PM
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Troy Bilt TB90BC 2-Cycle String Trimmer Won't Start

I let this Troy Bilt TB90BC 2-Cycle String Trimmer sit for probably 6 months in my garage. I tried to start it, and it won't start.

I used 10% ethanol gas when I mixed it with the oil, which now I know that ethanol gas is a big no-no for these kind of small engines. I know that now. I won't even put ethanol gas in my motorcycle now.

So I've replaced the primer bulb and the fuel tubing, and it still won't start. In fact, after pressing the clear rubber primer bulb it doesn't bounce back to shape quickly. It just stays pressed in and very slowly gets back to shape, like there's suction holding it pressed in.

I'm guessing the ethanol gas has made a varnish mess inside the engine.

What can I do to fix this?

FWIW, I poured some Sta-Bil in my generator when it was having trouble running after sitting for many months, and after letting it sit with the Sta-Bil in the gas for a few weeks, the generator now runs perfectly. Will Sta-Bil clear up any ethanol build up on my 2-cycle string trimmer?
 
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  #2  
Old 04-14-12, 06:39 PM
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The ethanol thing runs a little different from area to area in either the gas itself or in the philosophy regarding it. It can be made from different plant matter and is often produced at different somewhat local plants rather than pipe lined in from a common source. So your problems may or may not be directly related to the gasohol. Here in Iowa, we use it all the time, it's cheaper, prevents gas line freeze in the winter, and performs like gas without problems.


You might try dumping all the old gas out and with no throttle, full choke, with spark plug in, spin it over half dozen times to clear the fuel from the carb. Then put a tablespoon of fuel mix down the plug hole, half throttle, no choke and see if it will fire. If it tries to start, add fuel back to the tank and with half throttle, half choke, see it will take off. It will take a few pulls.
 

Last edited by marbobj; 04-14-12 at 07:35 PM.
  #3  
Old 08-06-12, 03:45 PM
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2 cycle trimmer

hey guys i have a 2 cycle trimmer that is the 27cc model...it was running fine and then stopped and wouldnt crank and then when pulling the starter cord it started making a horrible screeching sound and wouldnt even begin to start...i put a new spark plug in it out sound continues and no luck on starting.
 
  #4  
Old 08-06-12, 05:07 PM
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Does it have compression?
 
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Old 08-06-12, 08:29 PM
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@ Scottkeen, you have something stuck in the carburetor, get a rebuild kit and replace all the diaphragms, then try to prime. Should work. Good luck
bamarice13: sounds like it has been run to lean and is getting ready to lock up.
 
  #6  
Old 08-07-12, 03:00 PM
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i use the correct mixture of gas and oil...i do know that when i take the spark plug out and try to start it doesnt make that sound.
 
  #7  
Old 08-07-12, 08:07 PM
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I'm wondering if the crankshaft bearing has gone bad, causing the flywheel to rub the coil. Does it turn very easily without the spark plug? It does sound like the cylinder/piston got scored. Take the muffler off and have a look in the port to see the condition of them.
 
  #8  
Old 08-08-12, 09:44 AM
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if i have the spark plug out then it turns good likes it wants to crank but obviously it doesnt...i have the muffler out and it looks good inside best i can tell.
 
  #9  
Old 08-08-12, 09:46 AM
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It's hard to know what's making the noise, you'll have to pinpoint it.
 
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