Exhaust problems part 2!

[andy watson]

OK,

Got a flexible exhaust pipe from Mick Reeves for a fiver.  I have silver soldered the threaded end of the cut header pipe to it, and have solved my problem, but have a created another?

Because the exhaust is now a simple pipe I don't have a nipple to run back to the fuel tank to pressurise it.  Bearing in mind I am building a WWI biplane, so I won't be throwing around the air like an idiot, will it be ok, or is there a (simple) solution?

I don't know if it's relevant but the bottom of the fuel tank is about level with the engine

[Nick Lambert]

Hi Andy,

What engine is it? Four strokes can be set up to run fine without presure. You'll probably need to retune the needle to be a bit richer than the setting you have now.

[andy watson]

It's an OS 70 4 stroke.

Still brand new.

[Nick Lambert]

Hi Andy,

 Then that should work just fine without a pressure feed. 

 Nick

[andy watson]

Cheers

[fat head]

Hi Andy, I have only use a exaust once on a 4stroke and that was in a t/moth with a lazer engine just because of the port set up on these engines.  I run the tube forward with a cone shaped device to slightly persurize the tank with the prop wash on all planes i have with 4s, but i think you can set them with out this . I think they sound better with out the exausts and they also tend to fall off at some stage and are costly to replace.