fuel coming out of vent tubes

Re: fuel coming out of vent tubes

by RotaxOwner Admin » 7 years ago

RotaxOwner Admin

59 1.6k 16.6k

Have you reviewed this video:

https://www.rotax-owner.com/videos-topmenu/rotax-minute/454-carb-vent-lines

Re: fuel coming out of vent tubes

by Roy Evans » 7 years ago

Roy Evans

1 2 0

i have.. the fuel is coming out constanty out of both vent tubes while on the ground with the 3 inch tubes

Re: fuel coming out of vent tubes

by Rodrigo Echenique » 7 years ago

Rodrigo Echenique

5 19 0

Hi Roy,
Check that both carburators are perfectly vertical, if they are installed in an angle this can cause the neddle float to stuck and you will have a leak at the vents, if the carburators are perfectly vertical and you have a leak at the vent of both carburators you will need to disassemble them again and first check the flotability of each float then check that you don´t have any debris in the float neddle seat and check also the the tip the the float neddles are not damaged.
I s very strange that both carbs have a float neddle leak and more when they where rebuilt, for sure they are not well assembled.
If you did the work check it again and before closing the carburator bottom cup, check thta when you push the floats you have a perfect seal of the needle.

Also check the height of the floats when they push and close the neddle that supply the fuel

Regards

Re: fuel coming out of vent tubes

by Roy Evans » 7 years ago

Roy Evans

1 2 0

All have been rechecked by myself irmt-A and another a&p irmt again restarted and again fuel coming out of vent tubes... Is possible that the fuel pump is putting out more than 7.5 p.s.i. causing this problem?????

Re: fuel coming out of vent tubes

by Rodrigo Echenique » 7 years ago

Rodrigo Echenique

5 19 0

I don´t think so, check the flotability of your floats
Your fuel pump will give you about 5.5 psi and with this pressure and even with about 8 psi a good pair of floats and the needle valve will not open and this pressure.
Are you sure you installed the seat of the needle valves or your teied to clean the seats that maybe you damaged the seats of your needle valves of the floats?
Here I have some carbs, I will make a test at how much pressure they will open