victa 160cc help

[xn4tr1x]

Hey guys I've just purchased a pre-powertorque victa 160cc (full crank) it already has a decompression port replaced with a spark plug. its complete and started it on the bench, it cranked straight away I couldn't believe my eyes, this thing was sitting outside for 10yrs + never started.
Anywho. ive now just removed the carb and stuck a 250cc 4 stroke carbi on it and it now it wont start. i thought its just the carbi but then having a closer look, I've noticed without the carbi on the intake pipe i placed my finger covering the intake pipe without much force just resting there and tried starting it blows my finger out and in ??? both suck and blow feel equal is there ment to be a reed somewhere? i also noticed the diaphragm on the original carbi has a valve that moves in and out in sync acting like a reed valve. I've done searches but apparently there's no need for one, any help on this?
Thanks in advanced guys!

 

[Russ2251]

is there ment to be a reed somewhere?

To my knowledge Victa 2 cycle engines are piston ported which means there are no reeds.
As for the no start...the replacement carb you are using is too large for that size engine.
As a test, put everything back to original stock configuration and see if it starts.
If engine does not start in its stock configuration, it certainly will not start when modified.

 

[xn4tr1x]

Great thanks Russ2251, I've put everything back to original spec and it runs just fine.

Whats a good carby to use? I've read some people use chainsaw carbies but no description on what size.

 

[Russ2251]

Measure the venturi inside original carburetor throat.
The venturi is the narrowest part and would be roughly down in the middle of the carb body.
Carb you choose should have about that same dimension.
Admittedly, it is a little bit of trial and error.
A 3/4" (.750") venturi works well with my 2 cycle engines which are 141cc's each.