Two stroke strimmer...
 

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[Closed] Two stroke strimmer carb experts. Any ideas why....

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...my strimmer dies when I open the choke?

It's never let me down, always started first time until this morning.

I prime the carb, close the choke and it starts first pull. When I open the choke and depress the throttle it dies.

I whipped the carb off, gave it a quick blow through with the airline but it hasn't improved.

Should I strip the carb down completely?

EdIt I replaced the diaphragm at the bottom of the carb last year, it still looks ok.

It's a Kawasaki if that's any help.


 
Posted : 20/07/2013 7:53 pm
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Main jet blocked, fuel filter in the tank blocked or air leak.


 
Posted : 20/07/2013 7:56 pm
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I would of guessed air leak but stu covers all of it.


 
Posted : 20/07/2013 7:59 pm
 br
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[i]It's a Kawasaki if that's any help. [/i]

Is it painted green? 😉


 
Posted : 20/07/2013 8:01 pm
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Great stuff guys, I will get it stripped properly and report back.


 
Posted : 20/07/2013 8:19 pm
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Has it been left with fuel in the tank/carb for a long period? If so then the main jet will be gummed up. Carb needs stripping and cleaning in an ultrasonic bath for best results.

It's effectively running too lean as there isn't enough fuel for the available air hence why it runs fine with the choke on. However if it still dies even with the choke on then its the diaphragm in the carb (acts as a fuel pump)


 
Posted : 20/07/2013 8:35 pm
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However if it still dies even with the choke on then its the diaphragm in the carb

Or air leak or tank filter blocked or main jet blocked.

No way of telling unless it's sat in front of you and you can take a look. 🙂


 
Posted : 20/07/2013 8:43 pm
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Has it been left with fuel in the tank/carb for a long period? If so then the main jet will be gummed up. Carb needs stripping and cleaning in an ultrasonic bath for best results.

It's been sat for a week or so with fuel in the tank, in the past it sat much longer. I don't have an ultrasonic bath, what else could I use? I have an air line and a selection of thinners.

I did notice some tiny air bubbles in the priming bulb. I've never looked there before.


 
Posted : 20/07/2013 8:44 pm
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Squirt of carb cleaner down it's chuff will sometimes clear a light blockage.
Will also knock a large wasp out of the air and leave it dead before it hits the ground so, you know, don't sniff it! 🙂


 
Posted : 20/07/2013 8:50 pm
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I got a fully operational Mcculloch strimmer from the skip place last week for a tenner.

This doesn't help, I'm just chuffed.


 
Posted : 20/07/2013 8:52 pm
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However if it still dies even with the choke on then its the diaphragm in the carb
Or air leak or tank filter blocked or main jet blocked.

No way of telling unless it's sat in front of you and you can take a look.

tank filter would stop engine regardless if choke was on or off-would only restart if left for a few mins, main jet will stop it if choke off but will restart with choke straightaway, air leak would be difficult starting (spray carb/gaskets with easystart-not inlet/air filter to check)

If it dies after a consistant time every time then its probably the spark plug has failed-expands with heat and kills the spark. Restarts after cooling.

If it ran last week okay then its probably not mainjet gummed, drain if left for long periods though. Carb cleaner spray is okay on light gummage but ultrasonic is best.

Does it idle okay and for how long?


 
Posted : 21/07/2013 6:47 am
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Although I couldn't get it to run for more than a few seconds with the choke open, I did manage to get it to run for ten minutes while I cleared some nettles with the choke closed.

It would restart easily after it stalled when I opened the choke, by closing it again and pulling the cord.

It could probably do with a new plug anyway.


 
Posted : 21/07/2013 8:21 am
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What type of carb is it - Tilotson, Walbro?

Sounds like a diaphram issue to me - diaphram kits are easy to come by and also change the metering needle which should come as part of the kit. Once the carb (if one of the above) is rebuilt screw both the h and l screw right in and then screw out 1/2 a turn. Adjust the l screw until the enging idles smoothly adjust the h screw until until the engine just begins to 4 stroke i.e has gone past its max revs and on the h screw adjust and then you will hear the engine note just change as it is being sightly over fueled.

The carbs themselves as a whole are not too expensive though you might want to check for other air leakes - i.e worn crank seals etc before shelling out going and buying a Stihl!


 
Posted : 21/07/2013 8:37 am
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....before shelling out going and buying a Stihl

You have already anticipated my Plan B

I will have another look this afternoon.


 
Posted : 21/07/2013 8:51 am
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Im confused surely you only open the choke until it turns over then shut the choke off? this is the only way any of my gear has ever worked


 
Posted : 21/07/2013 9:00 am
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Damn. I set to carefully dismantling the carb, sorting out the parts on a sheet of cardboard. Somehow I've lost a tiny spring.

So I'm going to need to find a rebuild kit for a TK carb with the serial number DPR11-1 cast into the side. It was fitted to a Kawasaki TH43 strimmer of unknown vintage.

Google isn't helping too much, can anyone point me in the direction of someone who may stock parts.

Cheers MC.


 
Posted : 21/07/2013 4:16 pm
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Try Rowenacarbs.co.uk they have a good reputation.Though i've not heard of TK carbs they may know what is cross compatible or try arbtalk there are folks who know their stuff over there.


 
Posted : 21/07/2013 4:48 pm
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Thanks for the link.

Rowenacarb stock the kits and they are trying to sort me out with a spring.

Meanwhile Plan B is looking more appealing. I've found a Stihl FS400 strimmer locally, is there anything I should look out for when buying a used one?


 
Posted : 22/07/2013 10:07 am
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The new seal kit and spring and a soaking in easy start to degum the carb did the trick, thanks for the help on this folks.


 
Posted : 23/07/2013 12:31 pm

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