off topic carburetor question

getback wrote:hi team sports , I rebuilt a carburetor that was really bad for a friend on a atv ! boiled it out runs great but after cleaning all the factor sealant off it now has become poreiss ? seaping fuel thought the aluminum I know there is a spray to fix this but can't find it ? any suggestions  are appreciated . THANKS   ERIC

Are you looking for something like Permatex Spray-a-Gasket?

Eric:

What does this mean? "poreiss"

This calls into question what you consider "rebuilding a carburetor".  Did you use kit that included new gaskets?  Did you clean the carburetor jets?

I've rebuilt lots of carburetors both motorcylce and automotive and have been very thought throughout the whole process following the supplied kit instructions step-by-step.

If you are looking for a spray cleaner only I suggest "Gum-Out" available at most any automotive supply source.

The better you explain yourself the more we can be of assistance.

SuperDave  (aka: SD)

I have dealt with antique engines, with shellac coated cork floats.  The alcohol in modern gasoline is enough to strip the shellac, which then means the float sinks, and fuel pours out all over the place.  

I have also dealt with holed brass floats.  These can be repaired with solder, but sometimes "pop" if you don't get them dry inside and out.  Popping usually is the extra vapor burning off...it can be vigorous enough to cause serious injury when you are soldering.  Since there is no good way of removing the vapor perfectly I have simply let the float sit drained for a week and had no problem.

The float may also be out of alignment and simply need adjusted.

I would expect a carburetor on a ATV to use a floatless design.  I would also suspect the gaskets, diaphragm, float valve, and hoses before I barked up the porosity tree.  

Phil

(Paint the outside, and only the outside, with slow cure epoxy (30 min+).  Then wash in ammonia and use a plastic scrub pad, steel wool, or sandpaper to clean and scuff the epoxy.  Last paint with enamel paint since epoxy is not UV stable. This will cure porosity, but I doubt it is porosity.)

From Eric's description it appears the subject carburetor has been tampered with previously as I've yet see factory sealant that needed to be "stripped away".

Until such time Eric clarifies himself here I decline further comment.

SD

sorry had some earring to run, the carb. has never been into was green on the inside , stopped up, took it all the way apart boiled it in simple green/water mix . my spelling is not that great the pores in the aluminum was stripped of the sealant that the factor puts on them . now the bowel is seeping fuel through it , not flooding, runs great ! I have had this happen a few time on briggs 8 hp up draft carbs. I have seen on a hot rod show showing you how to rebuild Rochester quadrajet carburetors and they showed them sealing it back up with a spray. I have called several auto parts descriptors. so far no luck going to try auto fasteners next if I find out I will let u know , THANKS FOR THE REPLYS

Suggest you take the carb to someone EXPERIENCED in carburetor repair rather than DYI otherwise you'll get yourself terribly frustrated.

What you are seeing is a symptom rather than a cause.

Forget about Rochester Q-jets and what you saw on television.  They're for an entirely different application than the carburetor for an ATV.

EDIT:  Personally I find using compressed air far better than boiling to clean the innards of a carburetor.

SD

SuperDave wrote:Suggest you take the carb to someone EXPERIENCED in carburetor repair rather than DYI otherwise you'll get yourself terribly frustrated.

What you are seeing is a symptom rather than a cause.

Forget about Rochester Q-jets and what you saw on television.  They're for an entirely different application than the carburetor for an ATV.

EDIT:  Personally I find using compressed air far better than boiling to clean the innards of a carburetor.

SD

  thanks sd

U R welcome Eric.

Frustration can't help but hamper your enjoyment of most anything in life.

SD

I have witnessed the results of cleaning aluminium castings that has resulted in porosity on several occasions. The most memorable was a Yamaha XS 400 engine side cover.

I had stripped the engine and it was grubby - the aluminium had lost its sheen and was stained. When new it had a factory applied lacqeur and this had disappeared.

I cleaned it (and it was spotless afterwards!) by putting everything in the dishwasher with three dishwasher tablets.

The results were amazing! It gleamed!

Unfortunately, on reassembly and rebuilding the bike the side cover weeped oil through the aluminium like a very fine sieve. I left the cover to soak in turpentine for a few days and a few more days to dry off. Then I coated it with a special aluminium spray lacquer to seal it. This had to be repeated several times - the repair was never permanent.

"Porosity is a phenomenon that occurs in materials, especially castings, as they change state from liquid to solid during the manufacturing process. It has the form of surface and core imperfections which either effects the surface finish or as a leak path for gases and liquids. "


I discovered afterwards that aluminium castings and many other alloys are vacuum impregnated with sealant during manufacture. Cleaning treatments like the one that I applied, high temperature with an aggressive cleaner can remove this leaving a very clean but very leaky metal casting.

All I can suggest is looking for an aluminium lacquer to seal - but it won't be permanent. The porosity is much more than skin deep.

I have heard of old Honda 305cc cylinder heads being of poor quality casting that was too porous and allowed oil to weep out of it. The fix was to replace the head.

I doubt that the factory fix was to coat it in a coating that is only temporary. This just seems odd to me that this is even a problem with modern day metallurgy. If this indeed happening then it's a manufacturer defect and needs to be replaced.

You never did mention what type of carb it is, but being as most ATV's are Japanese I would guess Keihin. As such the only two points where fuel could leak from those is the float bowl gasket or the bowl drain screw. That's externally. Internally it could be the idle or main jet, but since you say it's running well then I doubt that is an issue.

Weird...... Hope you get it sorted.

Ron

Maybe I didn't explain properly. The vacuum sealing of aluminium castings is a standard process in manufacturing. There are a variety of sealants used and they are meant to be permanent.

However, aggressive cleaning solutions will remove the sealant. Any DIY fix after that will be temporary.

http://www.saranindustries.com/impregnation.html

ian1954 wrote:Maybe I didn't explain properly. The vacuum sealing of aluminium castings is a standard process in manufacturing. There are a variety of sealants used and they are meant to be permanent.

However, aggressive cleaning solutions will remove the sealant. Any DIY fix after that will be temporary.

http://www.saranindustries.com/impregnation.html

   thank s ian 1954 you are the man as always, I am going to suggest eather put up or get up off the $  its a  mikuni carb. ron thank you too!

As in so many things the "devil is in the details".

Accurate diagnosis 90% of mechanical repair. The other 10% is EASY.

There's an awfully lot of money spent on wrong guesses.

SD - The Voice of Experience

SuperDave wrote:As in so many things the "devil is in the details".

Accurate diagnosis 90% of mechanical repair.  The other 10% is EASY.

There's an awfully lot of money spent on wrong guesses.

SD - The Voice of Experience

Heh...I put a $40 egr valve on a couple weeks ago and really only needed $0.50 for the bolt I had to drill out...

Phil

Phil:

The point being?

SD

SuperDave wrote:Phil:

The point being?

SD

An example: "Accurate diagnosis 90% of mechanical repair.  The other 10% is EASY."

RknRusty wrote:

SuperDave wrote:Phil:

The point being?

SD

An example: "Accurate diagnosis 90% of mechanical repair.  The other 10% is EASY."

MY BIG OLD BUTT WORKING FROM THE CHAIR IE SIMPLE !!!!

RknRusty wrote:

SuperDave wrote:Phil:

The point being?

SD

An example: "Accurate diagnosis 90% of mechanical repair.  The other 10% is EASY."

This.

I could have bought the gaskets and bolt, but I didn't realize the real problem till later...

Phil