found a batch of weedeaters, fixed a couple already, one of them running funky, I've done everything i know and its still running wonky

[logert gogert]

alright guys, the other day i found a batch of weedeaters on the side of the road. there was one homelite straight shaft trimmer, one murray curved shaft ( i had no clue murray made weedeaters! ), a curved shaft orange weedeater ( its either a no name brand, or the name sticker is torn off ),
a feather lite curved shaft fx26 i believe?

first, i put new gas in them, none of them even primed so i didn't bother trying to start them. ( well, i did try to start them but only for a couple pulls )

so the first weedeater i tried to fix was the feather lite, first i put some gas in the throat of the carb, pulled the cord, it ran for about 3 seconds, okay good, the motors not blown.
i took the carb apart, gaskets were fine, it looked fairly clean, the only place a bit of dirt was on the little internal screen, but not enough dirt to where it shouldn't prime/run, then i cleaned the dirt out of the screen.
To make sure the carb worked i put a little bit of gas in the needle and seat thing ( on the bottom of the carb ) pushed in the needle and the gas slowly seeped down, okay, the carb is letting fuel through, good.
i then completely disassembled the carb, and threw it in the USC. after it was done a few cycles in the USC, i took it out, let it dry, and put in a new primer, lines, filter.
slapped the carb on and, i started to prime it, and after about 20 pumps the fuel started to get in the primer, but the primer would only fill up 1/6 of the way, and very once in a while after you pressed the prime, the primer would completely stop, then 5 seconds later it would start to slowly come back up, uuuuuh okay............?
despite the priming problem i tried to start it, 2nd pull it started, now after it started i wanted to make sure it stayed started so i full throttle, full choke, then flip it to no choke, then flip it to full choke, ( while on the throttle ). then after about 15 seconds of that i let off the throttle to see if it would idle, and of course it didn't idle and it shut off before my finger got to the throttle.

so after that i tried to start it again, i primed it, but this time no gas was going in the primer, and again it would get stuck once you press it in then 5 seconds later it would SLOWLY come back up.

despite that i still tried to start it again, after about 5 pulls this black, oily liquid comes out of the exaughst when I'm pulling the cord, i then think to myself, is it flooded?
i then pull the plug out, and oh YEAH, she's FLOODED, i then blow on the spark plug a bit to dry it off, and then with the spark plug out i pull the cord and as i suspected, a little bit of liquid comes out.
once the plug looks dry enough i put it back in, and try to start it.
then the same thing happens, that black liquid comes out the exaugst, oooookaaaaay..........?

so guys, what in the world is happening? are my rings worn out?
is there something with the carb?
I've done everything in my knowledge and I'm stumped

thanks in advance

-logan

 

[ILENGINE]

Looks like you have found the reason most shops don't repair the cube carbs anymore. Sounds like you are having check valve issues, coupled with a diaphragm valve not sealing. There were several companies that made cheap trimmers with orange shafts. The Murray is most likely a Walmart MTD Remington type trimmer. The Featherlite and the Murray both should have a minimum compression of 90 psi if you want to check them.

 

[logert gogert]

Looks like you have found the reason most shops don't repair the cube carbs anymore. Sounds like you are having check valve issues, coupled with a diaphragm valve not sealing. There were several companies that made cheap trimmers with orange shafts. The Murray is most likely a Walmart MTD Remington type trimmer. The Featherlite and the Murray both should have a minimum compression of 90 psi if you want to check them.

just saying, every thing i talked about was refering to JUST the featherlite

 

[logert gogert]

Looks like you have found the reason most shops don't repair the cube carbs anymore. Sounds like you are having check valve issues, coupled with a diaphragm valve not sealing. There were several companies that made cheap trimmers with orange shafts. The Murray is most likely a Walmart MTD Remington type trimmer. The Featherlite and the Murray both should have a minimum compression of 90 psi if you want to check them.

i dont think i have a compression checker/gauge

 

[StarTech]

Featherlites are not worth the trouble other than as training units.

I respectfully disagree with IL on the minimum compression as I have found that nearly all 2 cycles require at least 100+ psi to even start. Even at 100 psi I would still pull the muffler and check the PNC (cylinder and piston) for scoring.

Logan, there are several tools that you need to work on 2 cycles. A couple is a pressure/vac tester and a small engine compression gauge. Not all automotive compression gauges will work on on small engines.

But that cube carburetor pull the metering diaphragm cover and the diaphragm as it may have stiffen and is holding the metering valve open.

 

[ILENGINE]

Startech I said 90 because that is what Poulan and MTD show for minimum acceptable compression.

 

[StarTech]

Maybe it is just that my compression gauge scharder valve is more sensitive. I had only one Poulan chainsaw that started at 95 psi but it ran like crap and couldn't get off idle without it dying.