1. canard-aviators@canardzone.groups.io

Re: Marvel Carb Problem

Tom Smith
 

The brass floats have been around a long time and have been doing a fine job. Yes they can fail but not as often as the video
may lead you think. My floats have not had a car on top of them or was not placed in an oven. A little extreme I think. I understand
the point the video is making but I'm not about to remove my carb to install a blue float when my gold for now is doing it's job.


Tom Smith  A&P/IA
Long-EZ N12TS
Cell-707-592-0869
KVCB
KJ6PZN


-----Original Message-----
From: EJ Johnson ejandlinda@... [canard-aviators]
To: canard-aviators
Sent: Sat, Mar 16, 2019 7:05 am
Subject: Re: [c-a] Marvel Carb Problem



After that video I would think the blue is the only float needed. 

Long-EZ N36EJ my own little F16.
Elwood 'EJ' Johnson

On Mar 15, 2019, at 6:45 PM, Ron Springer ron228rj@... [canard-aviators] <canard-aviators@...> wrote:

 
Have you installed the new blue floats?


I just did that recently. Here is the motivational video ...


Ron

On Fri, Mar 15, 2019 at 6:43 PM 335dave@... [canard-aviators] <canard-aviators@...> wrote:
 
I have a Marvel-Schebler Carb MA-3PA in a Long-EZ with a 0-235L2C. 1650hrs, I've had it for over 1000 of those. The carb was overhauled some time when checking for the venturi AD (single piece or two piece). Apart from the idle cut off never working since electronic ignitions went on (maybe 6-700hrs ago) there have been no issues.

3 days ago at 200' climbing out the engine began to loose power. I had sufficient RPM left to climb a little more and return and land without incident. The engine had stopped before I landed, don't ask me when exactly. There was a pool of fuel under the plane.

Its now in a hangar with the head of maintenance for a small flying school He is very familiar with the engine and carb. They have several C152's. I have to use a licensed person as I didn't build this plane.

When adding fuel to the carb it will not shut off when the float gets to where it should be level. We are testing via an elbow in the fuel/water drain on the side of the carb and a tube pointed vertically. A bit like a sight gauge on a boiler. Whatever we do, with the fuel tuned on and fuel pump going the tube fills slowly gets to around the level of the floats and continues until overflowing. Sometimes it hesitates for a second or so as if the floats are catching on the sides internally and then letting go. In other words the carb will always overflow beyond the level of the floats.

We have, in separate operations, replaced the seat, the needle, the floats, the rectangular spring that is a part of that assembly, the finger screen in the fuel inlet, we have done lots of tapping on the sides of the carb during testing to see what that does. The float height has been set carefully per the manual. Of course I cleaned the inside of the carb thoroughly. There was a small amount of rust but otherwise nothing significant. 

Short of replacing the carb we are open to ideas please.    

Dave
LE VH-JZE
and building LE VH-XEZ
   



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