# homelite string trimmer surging and killing



## cajunh2s (Apr 19, 2007)

hiya guys

i have a 2 cycle weedeater i'm working on for my co-worker its a homelite
UT-20774 model....with a zama C1U carb with the B2 type body....

he told me it would start and die real quick....so i kinda figured it might be a carb issue....i had some zama C1U extra parts laying around....and since he mentioned he wanted it back as quick as possible....i figured i would take a shot with the parts i had...

so i tore the carb down and soaked for about an hour in carb cleaner
wanted to leave it longer but...it had a plastic choke lever and limiter caps and didn't want to eat those up...

blew out carb with compressed air....and installed the few new things i had
which was a new metering diaphram and primer bulb gasket...
i soaked the spark arrester as well...and got it nice and shiny..

went back together...and it popped on the second pull...acted like it wanted to start....but was having a hard time......i did get it to start after a bunch of pulls,hoping it just needed to be blown out more...and it would pick up...
but it would run ,surge and kill over and over......

i tried an experiment and pulled the muffler completly off to see if it would circulate air thru the system better.....and it did seem to start quicker with no muffler....but still would die and surge and kill....

i'm thinking next plan of attack will be to change the needle and seat....i have some parts ordered and on its way...carb overhaul kit....new fuel lines and filter...new spark arrester....

it also has a new spark plug and is getting good fire...but with that being said
the plug wire also has a nic in it....and you can see the white insulating wire under the black plug wire...so that also got my attention...

so what you guys think?.....am i going in the right direction thinking...needle valve and seat next?

cajun


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## hankster (Jan 1, 1998)

Check to make sure the cylinder bolts are tight.


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## glenjudy (Aug 26, 2006)

After following Hankster's advice, I would wrap a piece of ele tape around the nicked wire.
It would be better to remove limiter caps and jets before soaking in bath, an hour should be sufficient. Clean out inlet needle area with Qtip soaked in carb cleaner. Blow out all orifices and passages, especially idle ports in carb throat, with carb cleaner spray and compressed air.
I don't see a C1U-B2 in charts.
If you haven't already, download docs from this site:
http://www.zamacarb.com/tips.html
I'd be skeptical of using carb parts laying around to re-build. The appl chart from above will show correct carb kit part nos.
Tip: use original metering lever, it would have been at right height.
hope this helps,
thanks


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## cajunh2s (Apr 19, 2007)

yep....we both on the same page on electrical tape.....i did that the minute i found the nick...

the B2 had me a little puzzled also...if you look at the IPL of this weedeater
there are two carbs on the parts break down listed....each has a different type of choke....mine is the one listed as B2......and it has a B2 stamped on the carb body also....

and both are zama C1U carbs...just the choke is different is the only difference i could see....

i was a little concerned on the compression of this engine.....i don't have a compression tester...and the only thing i could do was...put my thumb over the spark plug hole while cranking engine.....it does try and push my thumb off with a good deal of force.....and i did get the engine to run for a while....so i'm hoping compression will be good enough after i rebuild the carb with new parts....and new fuel filter and lines..

cajun


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## geogrubb (Jul 28, 2006)

Sounds like bad fuel lines to me, I would suggest replacing the fuel lines before you buy a bunch of stuff you may not need. Have a good one. Geo


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## glenjudy (Aug 26, 2006)

cajunh2s said:


> ...if you look at the IPL of this weedeater
> there are two carbs on the parts break down listed....each has a different type of choke....mine is the one listed as B2......and it has a B2 stamped on the carb body also....
> 
> and both are zama C1U carbs...just the choke is different is the only difference i could see....


The difference in the IPL breakdown is the difference between a direct drive shaft or a clutch driven one.
The sub spec on C1U will be under the edge of one of the covers.


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## pyro_maniac69 (Aug 12, 2007)

hows the compression?

thats something I always check before I start working on any type of small 2-stroke engine


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## cajunh2s (Apr 19, 2007)

two things...lol.....#1 glenjudy you lost me with sub-spec.....what is the sub-spec?...on this carb?...does sub-spec tell me exactly what type carb it is?
thanks for the help on this one...

and #2 compression?....is there anyplace on line to find what compression should be on these small engines...information seems to be well hidden on line...as for as manuels and different specs and info..

is there a rule of thumb?...say all small two strokes should fall in say 100 lb range of compression?

cajun


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## pyro_maniac69 (Aug 12, 2007)

90 is generally the rule of thumb for bare min. compression


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## glenjudy (Aug 26, 2006)

cajunh2s said:


> two things...lol.....#1 glenjudy you lost me with sub-spec.....what is the sub-spec?...on this carb?...does sub-spec tell me exactly what type carb it is?
> thanks for the help on this one...
> 
> cajun


If you downloaded the files I referenced, you will find all Zama model nums in
http://www.zamacarb.com/pdfs/QuickKit_CR2008.pdf
it's the nums after C1U-xxxxxxx
the xxx(....) will be under one of the covers on edge of carb


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## cajunh2s (Apr 19, 2007)

hello again guys

received my parts for the weedeater today......installed new fuel lines and filter......and overhauled carb...with new gaskets and metering diahpram and needle valve...new spring....

got it back together....it fired up right off the bat.....would run a little while then quit.....i would restart...and it would run longer and longer each time.....till about the third time....she kept on running.....
so i guess fuel had to run through pretty good....or maybe air in the fuel lines.....till it straightened itself out....but doing good now...

so i reckon its fixed....lol.....thanks for all the input on this one....you guys are awesome

cajun
Randy


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