[richyrich7]

Just been given mantis no2    anyway it's leaking petrol, seems to be coming from the carb, the fuel filter is well gunged up, so I need a new one of those and possibly an air filter, I can get it to run but only for a 30 sec's at most, but I think that's down to the fuel filter. Any ideas re leak etc?

Cheers

Oh its 2 stroke, and how do you tell the age of one ?

[Gwiz]

I can't help with the filter, but i might be able to help with the leak.
If it's not coming from anywhere obvious (pipe or primer bulb) then i would reckon that the fuel shut off needle isn't seating correctly in the carb, and you will need to take it apart and see why.
if it hasn't been used for a long time, it's possible that it's all gummed up with stale fuel. A tin of carb cleaner and an air line will sort that out in no time at all. Take off the carb and strip it down carefully. The needle will have a tiny spring underneath it, Don't lose it, it would be a right pain trying to get another. The needle should go up and down a fraction freely, and should always return to the the seat fully to shut off your fuel supply. When the engine is runnig, this needle opens and closes many times a minute, if it gets stuck, either you won't get any fuel, or you might get too much.
You might have a gummed up filter in the fuel tank also, thats easy to remove and clean.
hope this helps, let me know how you get on.

[richyrich7]

Cheers Graham knew you'd know  

I'll get stripping and report back with piccies  

[shaun]

heres all the manuals mate if they are any help LINK

[richyrich7]

Cheers pal  any idea how you tell which model is which, there's a load of numbers on the chassis etc but to be honest apart from having white handles non folding handle bars it looks identical at the business end to my new one

[shaun]

not sure mate Ive never needed to look   touch wood all i know is the carb has a very fine adjustment.

[richyrich7]

not sure mate Ive never needed to look   touch wood all i know is the carb has a very fine adjustment.

Yeah it's got two teeny little adjusters, next week it'll be on swop shop as a pile of bits  

[Alfie]

not sure mate Ive never needed to look   touch wood all i know is the carb has a very fine adjustment.

Yeah it's got two teeny little adjusters, next week it'll be on swop shop as a pile of bits  

I think there are 2 engine models on the 2 stroke, SV4 & SV6. There should be a sticker or plate on the engine that mentions the above numbers. The SV6 is the newest model & I'm pretty sure yours will be an SV4 with white hand grips ..... but don't quote me  :roll:

[richyrich7]

 ta Graham

[richyrich7]

Ok I've took the carb to bits and it does look a bit mucky inside some brown deposits around some of the holes

key: blue line needle ?
red line hole it came out of

took the needle out it was a bit stiff and the end was black which wiped off.

so where do I spray ? the carb cleaner and whats the air line for ?

The petrol is leaking out of the carb itself coming out through the sir intake/choke on the side

It's an SV4 engine btw. [/IMG]

[Gwiz]

have you got the other side off as well?
the first thing to do, is to spray the carb cleaner down the hole indicated by the red line.BUT make sure you wear some gloves to keep the stuff off your hands. Also make sure you don't breath in the vapour. On the other side of the carb, there is a very tiny filter, DON'T lose it! The brass looking hole can often get gummed up as well, spray some carb cleaner down that as well.
I would always then give each hole a quick squirt, followed by a blast of air from the air line.
providing that the needle doesn't get stuck down the hole, and it pivots easy on that pin, you should be good to go.
just one thing though, I can't see, on your photo, the tiny little spring that sits under that needles pin and lever. It's very important.

[richyrich7]

Cheers Graham, yes I've got the little spring safe and I've took off the other side as well can't see a very fine filter anywhere but I could have missed it, definitely not lost it I undid it on white paper over the table      
I'll get some carb cleaner and try it all and let you know.
Thanks

[richyrich7]

Well it's all clear found some gunk in it that wouldnt clear with the carb cleaner so I poked it out with a fine bit of wire, looked like a small grain of sand, I found the little mesh filter you spoke of and that was crushed to one side but I've managed to straighten it out and re fit  

Still very hard to start, plugs fine, gaps right and when it does run, it needs revving with the throttle to keep it running and even then it will die after about 30 sec's or so  :?  I'm guessing that the throttle speed thingys have been fiddled with ?

[Gwiz]

carb still blocked mate. or u/s.
tank filter at a pinch.
my moneys on first two tho'

[richyrich7]

Whats u/s ?    new filter to tank plenty of flow of petrol.
I'll take to bits again  :roll: