cobra petrol breaker not starting

[marky2222]

Hello guys I have a atlas cobra petrol breaker
I bought it 2nd hand and since getting it I have got
It running a little bit after alot of pulls
but just for a few splutters
Then petrol just starts running out of the exhaust pipe
Can anyone suggest what could be wrong with it
I suspect a carburetor issue but what kind of issue
and what sort of things to look for wm plant (company) has had alook at it but
wanted £120 to fit a carb repair kit which i though was abit steep and turned it down also because they wernt sure if after they fitted the new seals and gaskets that it would work and i would still have to pay £120
Cheers
Mark

 

[the snooper]

i would have though that if its flooding that bad it would be the float in the carb not shutting off the fuel

i see its a 2 stroke depending what type of carb it may not have a float

 

[marky2222]

This is the parts manual here
am sure it dosent have a float


Page 14 about carb

http://www.crowdersupply.com/473.htm

 

[the snooper]

they are horrible carbs the things that go wrong with those are the diaphragms check them for holes they do have a needlevalve so that is worth a check to make sure its sealing also make sure you have a good spark

also check the rubber with the little flap valves make sure they are ok

 

[marky2222]

looking at the spare part page can you give me some numbers as to what to look at
also if i wasent getting a good spark what would be the problem there
cheers

 

[the snooper]

if you take the carb apart there will be a diaphragm at one end probably with a disc attatched check it for splits at the other end will be the valves you cant go wrong as these parts are also the seals between the covers
the round diaphragm should if i remeber connect to the needle valve via a little arm on a pivot which will be held in place with a screw

as for the igniion check for a strong blue spark if not try cleaning or replacing the plug

 

[marky2222]

so would 19 be what i need to check

 

[mike 109444]

Marky2222 The carb looks a lot like the one fitted to my 2 stroke flymo mower. The carb manufactures is "Tillotson".They have manuals to download. There web site mentions that there carbs are used on go karts as well!

 

[the snooper]

check 19,25 and 33 and blow out the jets
make sure you dont leave any lose parts in when you blow it oute

 

[stormin]

Yes #19 is probably the culprit and the needle #25. Carb kits usually come with those parts and the fuel pump diaphragm #33 for about a tenner.

You sure you are knocking the choke off at the first hint of firing when trying to start? That's the usual script for 2 strokes or you'll wet the plug and be pulling your arms off trying to start it.

 

[pedrobedro]

Petrol running out of the exhaust sounds a bit final for a two stroke as it means the whole crank case must be full of it. It looks like a lot of carbs of the type used in strimmers and brush cutters, Walbro are another manufacturer and there are repair kits available for them.

 

[steeo]

Have you checked that the piston and pot are ok especially if it 2 stroke ???

Work in a tool hire shop which does a lot of repairs to con saws, chain saws, strimmers, etc and if something come in not starting this is the 1st test I do on the tool as it is the easiest and quickest test.

Make sure it is switched off, take out the spark plug and place your finger over the hole and pullling the pull cord, if compression is good it should be blowing your finger off the hole if not your wasting your time till either piston or pot or both is replaced.

 

[marky2222]

Hello guys thanks a lot for all your advice

Yesterday I took the carb
Apart and looked at number 19# I could not
See any holes in it or any damage I then took
Out the screw that holds 25# ( the needle) I also could not see
Any problems with that (although I'm not sure what
I should be looking for with the needle) I then took the
Other side off and looked at 33# I also could not see any
Holes or problems with that I then washed all the carb
In petrol as I had no carb clean or air at the time
I then but it all back together and filled the tank with petrol but
Before I put the air filter back on I just gave it a little pull and petrol started to
Dribble out of the gold jet on the carb I'm not sure if this is ment to happen

I then fitted the air filter and the top cover and gave it about 5/6 pulls and yet again petrol
Dripping out of the exhaust I gave about another 10/11 pulls before giving up
I then went on to empty the breaker of fuel as there was no point in it sitting full if It wasn't going to work
Once empty barr a small bit in the bottom of the tank I decide to give it another pull or two first I got a few bangs then
Hey prestoe it started running but only for about 4 seconds then cut out I gave another pull and it started again for around 2 seconds then
Cut out and then back to just pulling and getting noting what would you suggest to that ??
To me it seems when it has a full tank its taking more fuel than
It needs and flooding the engine one thing I did think about was when I had the carb off and pushed the diaphragm in threw the hole in the carb
It didnt seem to be releasing the needle very good it was just slowly sliding back

also the screws with the springs on have been touch what affect would they have shoudl the be fully screwd in or fully out or half way ??

cheers

 

[pedrobedro]

Screw the screws in till they seat but not tight then screw back out again 1.5 full turns for a start. Check 33 as it is a valve and should operate when the diaphragm pumps. With no fuel in put a spoon of fuel down the plug hole and replace the plug then try starting it and it should fire for a few seconds.

 

[marky2222]

thanks i will give this a try

also does any one now what model the carb for this breaker is so i can get a repair kit this one on the link looks like what the one thats fitted is like

http://www.m-and-d.com/ST-615-112.html?mv_pc=00015

cheers

 

[marky2222]

bought this carb kit hope its the right one

http://www.ebay.co.uk/itm/ws/eBayIS...280338449053&ssPageName=ADME:B:EOIBSA:GB:1123

 

[mike 109444]

Have you seen the address on the package at the bottom of that ebay listing "Co Kerry Ireland". So it gets shiped to some one in the states then shiped to a customer in the UK! With all the fuel you are sending down your exaust and the fuel to ship the parts from the states... It's not a very green breaker. Still please do return to this post if it fixes it cosssss... I might have to get one for me flymo

 

[marky2222]

lmaooo i had a good laugh at that (not very green) lol when i went to the council recycling depot the other day with a load of mix stuff and said to the bloke which bin should i put this in /glass/rubble/card/plastic/metal/ he just goes throw it all in the end one genral waste it all goes in the ground anyways and also i wont be here to see any global warming effect lol i had to agree with him

ps still waiting on carb to arrive will update when arrived and fitted

 

[marky2222]

hello again guys carb repair kit came the other day so i got to work fitting the new gaskets / fuel filter etc the only thing i couldent replace was the needle as the one that came in the repair kit was massive compared to the one that was fitted dont now why this was when every thing else fitted fine any way i got it all fitted back togeather ajusted the screws with springs on as advised 1/5 turns
and hey presto after 4/5 pulls it was running like a dream!! so thanks alot for your advice and till my next problem over and out