newbie needing help

[boony]

good morning all ,I recently acuired a cosmo/sip 145-gas/gasless mig welder
i replaced the swan neck with a new part from a place in sheffield . The problem is when i try to weld with the gas off i feeds the wire okish but as soon as i turn the gas on it just gets caught near the two little wheels that feed the wire upto the nozzel any help would be appriciated .

 

[shenion]

Check the gap between the rollers and the liner. It should be as small as possible, usually just 2-3mm.

Could be bad or wrong size tip.

 

[boony]

i also got a few new tips but i can not understand why it would suddenly do it as soon as the gas is on .

 

[rtbcomp]

Just to clarify.

When you switch to gas do you change to gas-only wire? If so what dia and do you fit the appropriate tip?

 

[boony]

ive got the copper wrapped wire which i thought was just for gassed welding

 

[rtbcomp]

Assuming you have the correct tip, try increasing the wire feed slightly, with the gas it may be burning back and sticking at the tip.