carb moisture

[bkarp@roadrunner.com 6]

I put a new aftermarket carb on my magum12 wheelhorse mower,seems to run ok but the outside of the carb is covered in moisture,like it was soaked with a hose after a few minutes. very strange what could be going on ? thanks brent

[Jon Paulsen 290]

Condensation?

 

[Rick3478 428]

Not at all unusual.  Gasoline vaporizing in the venturi as air is sucked through makes it cold, and if the ambient air is humid, moisture will condense on the cold surfaces.  I've seen frost on carbs if the weather is cold enough, and a carb can actually freeze up and cause the engine to quit running.  Also can happen at altitude, and a lot of piston engine aircraft have carb heaters.

[ebinmaine 67,420]

4 minutes ago, Rick3478 said:

carb heaters

 

Yes sir. Yes sir. I've seen trucks with them as well.

[Handy Don 12,212]

High humidity is the key factor. It’s one reason early airplane pilots avoided clouds when using carburetor engines.

The other reason was that some clouds have aluminum linings (joke).

[bkarp@roadrunner.com 6]

thanks guys are temps are around 94 degrees and high humidity,sounds like that is what is happening.

[Achto 27,565]

1 hour ago, bkarp@roadrunner.com said:

I put a new aftermarket carb on my magum12

 

Is the venturi on your new carb smaller than the original? If the air is being forced through a smaller hole, the velocity of the air will be increased. The result of the faster moving air will cause more of a cooling effect which will create condensation in warm weather conditions. 

 

Had a Harley with a long aluminum intake on it that curved making the carb face towards the front of the bike. The intake would actually frost up at highway speeds, even in 90+ degree weather. 

Edited June 18 by Achto

[ebinmaine 67,420]

1 minute ago, Achto said:

Is the venturi on your new carb smaller than the original?

 

That's likely. 

 

ALL of the aftermarket big block carbs I've seen here were too small. 

 

 

[adsm08 2,046]

1 minute ago, ebinmaine said:

 

That's likely. 

 

ALL of the aftermarket big block carbs I've seen here were too small. 

 

 

That's what drill bits are for.

[ebinmaine 67,420]

1 minute ago, adsm08 said:

That's what drill bits are for.

Oh no no no.  

 

I mean the main body bore. 

 

I've had 2 or 3 "#30" replacement carbs that were more like 25, maybe 26....

 

That's not something I'll ever fix.  

 

I'll keep rebuilding OE Kohler carbs.  

 

 

[adsm08 2,046]

1 minute ago, ebinmaine said:

Oh no no no.  

 

I mean the main body bore. 

 

I've had 2 or 3 "#30" replacement carbs that were more like 25, maybe 26....

 

That's not something I'll ever fix.  

 

I'll keep rebuilding OE Kohler carbs.  

 

 

 

That's what Dremels and carbide burrs are for.

[ebinmaine 67,420]

2 minutes ago, adsm08 said:

 

That's what Dremels and carbide burrs are for.

As much fun as that sounds....

[Achto 27,565]

4 minutes ago, adsm08 said:

That's what Dremels and carbide burrs are for.

 

A better solution would be, gut the carb, grab a small rigid hone & your favorite beverage. Pull up a seat and hone the venturi out to the size you want. 

[adsm08 2,046]

1 hour ago, Achto said:

 

A better solution would be, gut the carb, grab a small rigid hone & your favorite beverage. Pull up a seat and hone the venturi out to the size you want. 

 

One of these days I'm going to rig up EFI on one of these things, just because.

[ebinmaine 67,420]

16 minutes ago, adsm08 said:

 

One of these days I'm going to rig up EFI on one of these things, just because.

 

I've talked to a local feller about that. 

Seems interesting.