TroyBilt TB22EC String Trimmer - No Start

RVII

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I have a string trimmer that had been sitting for a long time, and I thought I would try to get it running. I did the usual: cleaned the fuel tank, replace the fuel lines and filter, replace the carburetor, and fill with fresh gas/oil mix, but still no good. I pulled the engine to look at the piston, and sure enough, the cylinder was pretty scored up. I replaced the short block with a new assembly. The new assembly came with a new spark plug and coil pack. I set the coil spacing with my brass feeler gauge. I verified spark was good at the plug, and the compression built up to about 120 PSI, after 4 or 5 pulls on the recoil rope. Oh, I also verified that my primer bulb circuit was flowing a nice stream of return fuel to the tank. After all this, I am still unable to get this trimmer started. I started with the customary 1 1/2 turns out from seated on the low and high speed jets, but still no signs of life. So, I have spark. I have fuel. I have compression. And . . . the fuel mix that I am using works in my Echo leaf blower. Any thoughts on this?
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StarTech

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Have you tried to see if it will even hit with a little fuel added directly to the cylinder? Might be a flywheel to coil timing issue.
 

RVII

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I have not (yet). I will try that, once everyone finally wakes up. My new short block came with the flywheel already installed. I can't imagine it would be out of time, but who knows these days . . .

What are your thoughts on the premixed cans of fuel/oil?

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StarTech

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Never tried them but I am cheap and mix my own shop fuel mix here. I was out yesterday cleaning one of my customer's Dingos with it.

I let others voice their opinions on it as I kinda see it as marketing scheme myself, just for very lazy people but that is just my opinion.
 

RVII

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Understood. I will try my current mix, directly into the cylinder and see if it wants to start. More to come . . .
 

RVII

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Never tried them but I am cheap and mix my own shop fuel mix here. I was out yesterday cleaning one of my customer's Dingos with it.

I let others voice their opinions on it as I kinda see it as marketing scheme myself, just for very lazy people but that is just my opinion.
I tried putting my 2-cycle gas mix directly into the cylinder, but had no luck getting the thing to fire off. I double checked my spark and checked my spark plug gap. All good.

Below are some images of the short block I removed. I compared the location of the piston in its stroke to the feel of the permanent magnet passing the coil, and both the new engine and the old engine seem to be showing the same resistance, in the same cycle position, when the permanent magnet passes the coil. I am at a loss . . .

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RVII

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I tried putting my 2-cycle gas mix directly into the cylinder, but had no luck getting the thing to fire off. I double checked my spark and checked my spark plug gap. All good.

Below are some images of the short block I removed. I compared the location of the piston in its stroke to the feel of the permanent magnet passing the coil, and both the new engine and the old engine seem to be showing the same resistance, in the same cycle position, when the permanent magnet passes the coil. I am at a loss . . .

View attachment 63163
Other than sealing out debris from the crankcase, does the rear cover o-ring (#4) provide any sealing properties that require a tight seal? Fuel delivery is created by the downward stroke of the piston, correct?
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StarTech

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This is a two cycle engine and crankcase is part of the intake system so yes that cover requires a tight seal.

With fuel directly introduced it should had hit if the timing is correct even with the crankcase partially unsealed.

I'm not there to look for myself but something is definitely not right.
 

Tbone0106

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I have not (yet). I will try that, once everyone finally wakes up. My new short block came with the flywheel already installed. I can't imagine it would be out of time, but who knows these days . . .

What are your thoughts on the premixed cans of fuel/oil?

View attachment 63162
I use this stuff, but not all the time. I like to run regular pump gas through most of the season, when I'm using the machines regularly. Then I switch to this stuff around the first of September. The ethanol in the pump gas will do bad things while everything sits over the winter, so I wean my 2-strokes onto the canned fuel before the snow flies. That way, they're ready to go in the spring. (My little snow-thrower is an exception; I use the canned stuff exclusively in that.)

Where I live, the nearest non-ethanol gas is 35-40 miles away, out on a marina fuel dock. The canned stuff is pretty pricey, but so is driving my truck 80 miles to fetch pure gas (at a premium price).
 

RVII

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I use this stuff, but not all the time. I like to run regular pump gas through most of the season, when I'm using the machines regularly. Then I switch to this stuff around the first of September. The ethanol in the pump gas will do bad things while everything sits over the winter, so I wean my 2-strokes onto the canned fuel before the snow flies. That way, they're ready to go in the spring. (My little snow-thrower is an exception; I use the canned stuff exclusively in that.)

Where I live, the nearest non-ethanol gas is 35-40 miles away, out on a marina fuel dock. The canned stuff is pretty pricey, but so is driving my truck 80 miles to fetch pure gas (at a premium price).
Good to know. I am still getting my butt kicked by this trimmer. New engine, new carb, new coil, new spark plug, new fuel lines and filter - No start . . . Frustrating, to say the least. Replacing the carburetor insulator and o-ring style gaskets on this part and the rear crankcase cover next. It's got to be something simple . . . I have compression, fuel, and spark.
 
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