TroyBilt TB22EC String Trimmer - No Start

[Tbone0106]

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.

A few thoughts.....

First, I've seen instances where the fuel lines on these little carbs are hooked up backwards. Some folks don't understand that the primer bulb on these things is designed to gently draw fuel to the carb by suction. The discharge (pressure) line from the primer bulb should run directly to the fuel tank, and the suction line should go directly to the "high" side of the carb. Getting these lines mixed up could bypass the carb completely or even pump gas OUT of the carb. Yeah, it's an amateur's mistake, but we're all amateurs until we ain't.

Second, I've seen instances where the primer bulb was overused, and the carb literally floods. Hell, it hasn't been that long ago when NOTHING had a primer bulb on it! They're made mainly to save you a few pulls on the rope; that's all.

Third, you might try backing the mixture screws out a half turn or even a full turn from the "customary 1 1/2 turns." That setting may be customary, but it ain't carved in stone. Many is the time I couldn't get a burp out of a little engine at 1 1/2 turns, but found success (or at least some burping) at a richer setting.

Good luck!

 

[bertsmobile1]

There is a right way to do this job and there is a wrong way
Doing it the wrong way and your butt will hurt.
So now in place of finding out what the problem was in the first place you have added 8 new potential sources of failure .
So IMHO put it all back together as it was in the first place then methodically work your way through to locate the problem first before you start throwing random parts at it .
And if they were cheap amazon/ebay parts then very good chance some if not all of them were faulty parts that the QC section rejected in the first place .
Or methodically work your way through the trimmer as it is
You start by pressure testing the fuel tank & vent
Then you pressure test the crankcase
then you pressure test the carb
Unless your cylinder compression tester is specically designed for small engines ( $$$$$ ) then your PSI figures are meaningless
IF you have fuel compression & spark then the engine will fire .
The lazy way is to shoot a VERY VERY VERY short shot of carb cleaner ( starting fluid if you have no CC ) down the plug hole & try to start
No bang = timing out, low compression, bad plug or blocked exhaust
If that works then it is another short shot down the carb
No bang = bad crankcase seals or blocked exhaust or piston installed backwards ( yes it happens )

 

[RVII]

There is a right way to do this job and there is a wrong way
Doing it the wrong way and your butt will hurt.
So now in place of finding out what the problem was in the first place you have added 8 new potential sources of failure .
So IMHO put it all back together as it was in the first place then methodically work your way through to locate the problem first before you start throwing random parts at it .
And if they were cheap amazon/ebay parts then very good chance some if not all of them were faulty parts that the QC section rejected in the first place .
Or methodically work your way through the trimmer as it is
You start by pressure testing the fuel tank & vent
Then you pressure test the crankcase
then you pressure test the carb
Unless your cylinder compression tester is specically designed for small engines ( $$$$$ ) then your PSI figures are meaningless
IF you have fuel compression & spark then the engine will fire .
The lazy way is to shoot a VERY VERY VERY short shot of carb cleaner ( starting fluid if you have no CC ) down the plug hole & try to start
No bang = timing out, low compression, bad plug or blocked exhaust
If that works then it is another short shot down the carb
No bang = bad crankcase seals or blocked exhaust or piston installed backwards ( yes it happens )

I appreciate the candid reply. I should know better from working in the automotive industry. I have the original carburetor, and I can clean that out and re-use. The replacement carb is aftermarket. The engine and ignition module (coil) are MTD. I will retrace my steps and see if I can get the engine to attempt to fire, then follow your suggestions. What turned out to be a free weed trimmer from my Dad has turned out to cost me almost more than the tool is worth . . . lesson learned.

 

[bertsmobile1]

Well I am from OZ where we have sensible gun laws so we speak our minds without the fear that the other party will whip out a fire arm and remove our minds from our bodies .
The down side of forums like this one is every body has their "pet problem" the one that caused them untold grief which they subconsciously project onto every one else without taking the time to read through the posts properly ( and I do it too ).
As all of the full time techs will tell you the most difficult part is the diagnosis .
We live in a time when just about every thing will tell you what is wrong , plug in the machine and read off the diagnosis
Having to do the whole thing from scratch is a lot harder & takes a lot more experiance to get down pat.

Small hand held engines are a bigger problem because they are so sensitive and the slightest of problem will have them inoperable.
It is quite weird that mowers are lazy engines and will run ( badly ) over a massive range of mal adjustments
Small hand helds are working to their limit so any mal adjustment and they are non starters .
So we go from one extreme to the other

 

[RVII]

Well, it finally started, and I was able to adjust the aftermarket carburetor to maintain a respectable idle and provide crisp throttle response to full throttle. I replaced the intake insulator and o-rings, and the crankcase o-ring, and the machine started. It only took a few pulls on the cord, and the machine was off and running.

I appreciate all the input from the forum members. This was a costly lesson, but hey, I basically have a new trimmer now . . . Thank you all.