String Trimmer only starts when I spray carb cleaner in the carb

[finfan1313]

Trimmer (John Deere T105C - 2009) didn't start at all, so I cleaned the old carb, no luck. I replaced

• carb
• spark plug (tested, it sparks)
• fuel filter
• fuel lines
• air filter

I adjusted the throttle cable because it was loose, (worked, but was loose)

Now it runs great if I spray carb cleaner in it first, but won't start normally. I can do the whole yard with it running fine, but if I turn it off, it won't start again, even hot. It DOES seem to want to shut off if I leave it idling longer than a few seconds, and it's idling high enough that the head still turns.

I've noticed that it leaks from the gas cap. I'm not sure if this has anything to do with whether or not it will start, but I've been unsuccessful finding a replacement gas cap. I purchased one online, but it also leaked, so I'm still using the original.

I'm at the end of my small engine knowledge.

This carb is the 2 hole carb like the one below. Any thoughts would be greatly appreciated:

 

[finfan1313]

bump

 

[upupandaway]

-dies if idle
-fuel leaks at cap

For starters, u need to replace\repair the gas cap. It is a rebranded Echo 80'ish trimmer so look around for a similar cap.
If you want to test before u buy a cap, take plastic wrap and put it over the fuel tank and put the cap on. That will temporarily fix the leak issue and tell u quick if these 2 issues and likely the start\restart issue also are resolved.

 

[StarTech]

Sounds either a gasket leaking Intake and cylinder gaskets along crankshaft seals or the engine is worn out and the compression is right at 100 psi. With right at 100 psi there is enough compression running but needs the starter fluid to boost it at start up.

And the OP can find an Echo cap to fit as JD is ridiculous on their cap. Also gas leak may not even be the cap but could be the rubber tank grommet where the fuel lines enter the tank.

 

[finfan1313]

I've replaced the gas cap, and rubber grommet in the gas tank when I replaced the fuel lines.

I don't have a compression tester, but given it's a 2009 I suppose the engine could be shot.

The gaskets in the carb are new so I'd hope they're not leaking. There's one gasket right under the air filter though that's older I think, and I suppose that could be the issue. I'll try that.

 

[bertsmobile1]

Joe pace from the Husqvarna service school has a series of you tube videos titled "2 stroke diagnostics ".
He is a dead boring presented but the methodical approach is wha you need starting with pressure testing the fuel tank and the cap
They are oly about 15 min a hit look at all 4 of them in order.

You very well could have a leaking crankcase seal but start from the beginning it ends up being a lot cheaper that way .

 

[sgkent]

does this carb have mixture adjustments? If so get the correct tool and adjust the mixture while it is running. I glanced back thru the comments and did not see anywhere that the idle and high speed mixtures have been properly adjusted.

 

[finfan1313]

does this carb have mixture adjustments? If so get the correct tool and adjust the mixture while it is running. I glanced back thru the comments and did not see anywhere that the idle and high speed mixtures have been properly adjusted.

Good thought, but it does not have adjustment screws.

 

[sgkent]

you'll have to tell people here more about the unit. there are many T105C models and have different carbs. Did you buy the replacement from John Deere? Using fresh fuel?