Corrosion in the carb

[Tom-D]

Yes, the little spring that expands the leather seal is corroded into several pieces, causing the accelerator pump not to work, The engine quit when the throttle was pushed in quickly.

What would cause this ?

 

[gkainz]

water in the fuel? I assume you know the answer and this is a brain teaser quiz?

 

[ScottM]

What would cause this ?

oxidation.

 

[SCCutler]

Water, carried by ethanol in fuel.

 

[Tom-D]

water in the fuel? I assume you know the answer and this is a brain teaser quiz?

It is not, If I knew the answer for sure I'd post it.

 

[Tom-D]

oxidation.

Don't you need O2 to get oxidation? how could you get that if the spring was immersed in 100ll ,,,,,,,, just asking?

 

[Tom-D]

Water, carried by ethanol in fuel.

I think you are pretty close.

This is what I posed in the RED boards, as an answer to Henning.

This label carb was built by Precision Airmotive during their first 2 years of ownership of the production certificate. This carb was installed in 1999, and served well until this year.

I don't believe the carb would have lasted this long if it were bad off the shelf.

During this owner's tenure the fuel tank necks were changed, the fuel selector valve was rebuilt, and the gascolator had new gaskets installed, and the aircraft has a new fuel line to the carb installed.

I believe this is just another event in trying to solve problems caused by the prior owner using dry gas as a cure for water in the fuel.

And I am wondering if this isn't just the prelude to what we will see if we are forced to use fuel with an alcohol additive.

 

[ScottM]

Don't you need O2 to get oxidation? how could you get that if the spring was immersed in 100ll ,,,,,,,, just asking?

Oxygen can be dissolved in the fluid and that will cause oxidation too. Some fuel companies for autos actually go out of their way to oxygenate fuels by adding compounds that will help the fuel carry more O2 in it.

 

[Tom-D]

Oxygen can be dissolved in the fluid and that will cause oxidation too. Some fuel companies for autos actually go out of their way to oxygenate fuels by adding compounds that will help the fuel carry more O2 in it.

Let's talk 100LL, that's where we are. car fuel is crap. full of sh-- we don't like.

 

[Capt. Geoffrey Thorpe]

I believe this is just another event in trying to solve problems caused by the prior owner using dry gas as a cure for water in the fuel.

And I am wondering if this isn't just the prelude to what we will see if we are forced to use fuel with an alcohol additive.

Well, if the previous owner was using dry gas on a regular basis, then there is your answer. I would shine an appropriate light into the fuel tank to look for corrosion there as well.

 

[Tom-D]

For those interested in seeing the rest of the carb parts

Note the accelerator pump plunger is missing (POO) and the accelerator pump nozzle is the tiny brass pipe coming out of the base and sticking up into the venturi area.

also note that this carb has a white plastic float, and rubber tipped needle valve. those were a change that Precision placed in the carb. They never were able to answer why they went from a brass float to a plastic one. nor could they tell me why they went to a rubber tipped needle valve rather than a metal one.

This is a case of fixing things until they are broke, and a prime example of how lawyers can sell parts thru the AD system. see all the ADs on MA-3SPA carbs on file. (this a POS and doesn't have any ADs.