Carb Float SB

Just thought I would share my experience with replacing the carb float on my 0-320 recently. In general it was pretty easy to do, and nice to get the white plastic float out of the carb for sure.

Here's a link to the entire story.

http://flying.karmy.com/?p=165

Hi Andy,
Thanks for the great article...I will use it for reference when I swap out my floats. Can you tell me how much the float kit costs from Aero and what parts come with the kit?

it seems to be cheaper at Spruce.. part # is 666-1002-F for your carb..

Radomir said:

it seems to be cheaper at Spruce.. part # is 666-1002-F for your carb..

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ACS's web price is $17 less than what I paid A.E.R.O. for my float kit but I had it the next day. If I had a Spruce order ready I wouldn't hesitate ordering from them. A.E.R.O. has always treated me fairly and has usually come up with the weird things that I have needed from time to time; i.e. used longer dip stick tube and dip stick.

1 x FLOAT KIT, SMALL MA (Float Kits) (666-1000--F) = $127.41 + shipping charges.

The kit has a new set of bowl gaskets, 4 new tab washers & the float

Fun for Tonight

Found the white floats while rejettng the carb. I pick up the kit tonight and will install it. Very timely, thanks Andy.

This was a great timing reminder for me too...just getting ready to install the FAB...need to check on this first.

Float valve seat

The instructions call for removing the float valve seat and reinstalling with the included gasket. Are you all doing this or simply installing the new float and making adjustments for clearance keeping the float valve seat in place.

Paul

Paul Eckenroth said:

The instructions call for removing the float valve seat and reinstalling with the included gasket. Are you all doing this or simply installing the new float and making adjustments for clearance keeping the float valve seat in place.

Paul

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You only need to do this if needed. Mine was just fine without making this change.

I would personally recommend trying to find a new metal float. Someone said that Avstar makes them still. Too many SB on the different floats out there right now, and none of them are proven except the metal one.

Paul Eckenroth said:

Are you all doing this or simply installing the new float and making adjustments for clearance keeping the float valve seat in place.

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I left the valve seat alone and simply adjusted the small metal tabs until the proper clearance & range of motion was set for the little pin with the plunger on it. (nice technical terms)

I did have to bend one arm of the float to get it perfectly level with both sides showing proper clearance, and had to install / remove it more than a few times to get the tab bent properly to adjust the float height. You only have to think about bending it and it moves.

osxuser said:

I would personally recommend trying to find a new metal float. Someone said that Avstar makes them still. Too many SB on the different floats out there right now, and none of them are proven except the metal one.

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Doesn't the SB include metal floats?

No, but ACS has a Kelly metal float kit for $117.

Actually the Volare SB DOES apply to metal floats...

http://www.tempestplus.com/SB-2%20Volare%20Carburetors%2002-01-2009.pdf

painless said:

Doesn't the SB include metal floats?

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RV7AV8R said:

No, but ACS has a Kelly metal float kit for $117.

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cjensen said:

Actually the Volare SB DOES apply to metal floats...

http://www.tempestplus.com/SB-2 Volare Carburetors 02-01-2009.pdf

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Volare sez change them all unless they are the new blue one. Kelly sez.."don't listen to Volare, ours are good".

Problem is, unless you have a good paper trail or did it yourself, you have no idea who made the metal float in your carb.

It's your choice who to follow.

Since Volare is in the carb making business and I am not, I consider them the experts on this subject and followed their recommendations.

I have been under the impression that if my carb has a metal float, which it does, I am happy as a clam.

Anyone have to replace a metal float due to corrosion/leaking?? I guess I need a clarification. Is this SB mandatory?

Also, wouldn't a poor running engine on the ground be a first clue that you have a bad float? What happens if it is a catastophic failure in flight? I assume your engine would run rough as all getout. Or would it, as the British would say, "fail to proceed?"

My in-flight experince with a sunken carb float

In the interest of overall RV safety, this information could be very helpful to any RV owner that don't already know what a total sunken float in-flight experience is like. 15-years ago in my C23 Beech Sundowner, I had a float completely sink just after takeoff. At the climb attitude with low altitude over the trees, my power dropped-off well below the green arch, the engine shook vigorously, and I had multiple pilot reports that I was trailing black smoke -- just what I wanted to here. I ran my emergency checklist, and when I pulled the carb heat-on, the engine nearly died, so I undid that quickly. When I dropped the nose down to look for a suitable landing site just past the trees, the engine stated developing full-power again , but as I brought the deck-angle back up to climb attitude, the engine got very sick again . We got back into that airport but could only achieve 300 feet AGL around the pattern . Once back on the ground, the engine ran fine. One clue leading up this event was at idle as I would pull the mixture for idle cut-off, the rpm would increase by 300 rpm just before shutdown, and the engine was somewhat rough at idle. When we pulled the carb off and tilted it up a few degrees, raw fuel ran out of the vent tube inside the throat of the carb. I also found black material floating round in the float bowl that could have easily clogged up the jets. Now, in my RV-9A I'm almost sure that I have the white plastic float given date it was overhauled. I haven't had any problems with it yet, but every single time I shutdown, I go full rich, back to idle and then slowly pull the mixture knob to cut-off. Any rough idling or too much increase in rpm I would know that flight. I don't know about you guys, but I'm personally very happy to see Volare LLC "stepping up to the plate" and addressing this long standing float issue that Precision AirMotive didn't really address properly -- right up until they lost their liability insurance last year.

John,
Flying RV-9A
N119WB

Just to answer the question above, the FAA does not require compliance with SB's, compliance with AD's are required (for certified acft). That being said also understand that often a manufacturer can issue a SB which may be the technical basis of a future AD. However just in case it seems too easy or obvious - a review of ADs will also show cases of SBs "gone bad" where it turns out mods suggested ("directed") by a manufacturer to correct a problem turned out to have their own problems (maybe worse than the one they were trying to correct). Scary words when you read things like "non compliance relieves us of of all responsibility" in a SB but sometimes a little discretion and research is prudent. Sorry, but you need to determine your own comfort level - or ask an A&P knowledgeable with the problem. I'm for upgrades and improvement but personally I hate to fix things that aren't broken.

Doug Drewry

RV7AV8R said:

No, but ACS has a Kelly metal float kit for $117.

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Oops, I thought you were asking if the Metal Float was included as a solution to the problem plastic floats. I meant No, they have a solid foam float (the smurf Blue one) as the solution. The other solution is to use the Kelly metal float which Kelly says has been used since 1985 (or thereabouts) with out problems.

Far be it from me to push my opinion on this particular subject on anyone. First off, the new floats (BLUE) are solid epoxy, which as I understand it are NOT the same as the solid FOAM floats that were LAST YEARS solution to this "problem". I too have had limited experience with sunken floats, and it's no picnic, but the reality of the situation is this:

EVERY single solution thus far has lasted less than 2 years before it is reverted back to the metal float. From what I can see, most of the metal float problems have been the result of carbs in service for FAR too long between overhauls. If they keep working, people wrongly assume that they don't need regular maintenance. I'll stick with WHATEVER brand metal float happens to be in whatever carb I have. If I get one with the new float, I'll stick with that until something goes wrong with that design (who knows what?) and they revert back to the metal once more.

Incident report that occurred in 2008

My thinking is to always be on the lookout for a bad float every time you fly regardless of the float you have. If your idle is rough or you see too much increase at idle-cut-off, then suspect the float. Also, keep in mind that if your float sinks too much and your engine dies at idle you could be spilling raw fuel out of your carb and have a fire hazard on the ground. If every pilot at engine shutdown went to idle, pushed the mixture full rich, then slowly pull the mixture knob back until the engine stops normally, your float is most likely good. However, if you have a rough idle, if you have a substantial increase in RPM just before shutdown as you pull the mixture knob to cut-off, or if your engine stops while idling, these are all really good reasons to suspect the float. The following is an incident report that occurred in 2007 with the white float sinking:

http://www.aaib.gov.uk/cms_resources/Piper PA-28-161, G-BGPJ 08-07.pdf

John
Flying RV9A
N119WB

SUPERSEDED SERVICE BULLETIN MSA-13

painless said:

I have been under the impression that if my carb has a metal float, which it does, I am happy as a clam.

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Maybe or maybe not ... Ours didn't the new float and we were not....

painless said:

Anyone have to replace a metal float due to corrosion/leaking??

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Yes

painless said:

I guess I need a clarification. Is this SB mandatory?

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Well depending on how you read things.... Yes it is mandatory...
The insurance company will certainly think so...

MANUFACTURER’S SERVICE BULLETINS
The FAA states that whenever an aircraft or engine manufacturer
determines, through service experience, that its product
may be improved by some modification, or that the service
life of its product may be extended by some particular maintenance
or repair, that manufacturer may issue a service bulletin.
The latter will tell what the trouble is and how to remedy it.
The service bulletin is mandatory because it supplements the
manufacturer’s maintenance manual that is required by FARs.

Service Bulletin: SB-5
SUPERSEDED SERVICE BULLETIN MSA-13

Comply with Volare Service Bulletins Nos. SB-2 & SB-4. Precision Service Bulletin MSA-13 should be marked “No Longer Active – Replaced by Volare Service Bulletin No. SB-2.”

Bulletin No. SB-2 Revision: A

Subject: Required Replacement of Foam and Hollow Floats

Compliance: In order to maintain flight safety, within 30 days of the date of issuance of this Flight Safety Service Bulletin, each owner of a Volare Float Carburetor not equipped with a solid, blue epoxy float is requested and strongly encouraged to inspect the carburetor and to re-inspect the carburetor at 30-day intervals thereafter until the float is replaced by a solid, blue epoxy float in accordance with the instructions in paragraph 6 of this bulletin. Failure to follow this advice may result in engine malfunction, damage, injury or death.