First engine start carb issue

[Roger Lee]

Hi Ed,

 

I hope this is only a single page post!

 

I went yesterday to help a guy on a kit built first start up for his 912ULS engine. Start up was okay. The carbs needed to be synced so I put my gauges on. Things looked good for the first 2-3 minutes and then the balance became worse. The vacuum between carbs became worse. Reset things after a shut down and restarted and the idle was within .5" vacuum between carbs at idle. The high end adjustment was off and took a little more adjustment than I thought. Then back to idle and the vacuum now was 12" off and it was shaking like it was idling on 2 cylinders. He put all his own hoses on since it was a kit.

 

I would bet any amount of money you can tell me what was wrong and why the vacuum was so far off between carbs???????

 

 

I really hope this stays a one page post! :lol: :lol:

[Ed Cesnalis]

Barbed fittings and rubber hoses are the dumbest idea employed on our aircraft.

 

The fix is simple and cheap and has made it all the way to our fuel pumps.

 

Beaded fittings are compatible with rubber hoses not barbed fittings even if they are widely used.

 

...I would bet any amount of money you can tell me what was wrong and why the vacuum was so far off between carbs???????

 

 

I really hope this stays a one page post! :lol: :lol:

 

Pressure differential?

 

I wouldn't sweat the long threads, the virtual ink is free.

[Roger Lee]

It was indeed debris in the carb bowl for the same reason as people who do the hose change get debris. poor hose choice, poor cutting technique, wrong clamps, too much clamp pressure and not blowing the hose out before it goes over the fittings. When needles on the vacuum gauge split like that you might as well stop and clean things out.

Maybe we should have the Admin lock this thread out now. It has enough post.