Carb Icing

A general, non-powerplant specific, discussion on airboat technology, ie., hulls, rigging, polymer, etc..
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lbdb1a
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Carb Icing

Post by lbdb1a » Thu Jun 21, 2012 12:27 am

To anyone interested,

Carb icing can be a problem even in Florida under certain conditions ie: high humidity,low temp etc. so i have been working on a solution that is working for me.

I have an aircraft side draft carb. that i have installed two 12volt ,70 watt heating pads on. This is a total of 140 watts @ 12 volts. The pads heat up to 250-300 degrees F very quickly.

Just flip the switch and you have carb heat.

Larry
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lbdb1a
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Re: Carb Icing

Post by lbdb1a » Thu Jun 21, 2012 12:40 am

Another view...

Larry
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lbdb1a
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Re: Carb Icing

Post by lbdb1a » Thu Jun 21, 2012 12:44 am

Before it starts..............yes maybe i should have just gone with fuel injection............ :dontknow: ... :rebel:

Larry

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JB550
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Re: Carb Icing

Post by JB550 » Thu Jun 21, 2012 1:03 am

Lol. Actually your setup looks bad a$$.

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Whitebear
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Re: Carb Icing

Post by Whitebear » Thu Jun 21, 2012 1:18 am

Your setup probably doesn't rob HP like in an airplane when you hit the carb heat and it puts hot air in the carb, though it does load the alternator to some degree. Your system is probably better suited to airboats. Let us know how it performs and if you notice any HP drop when its on.
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Re: Carb Icing

Post by Uhairball » Thu Jun 21, 2012 6:40 am

Or, you could stop and drink a cold beer while waiting on the ice to melt..
Not really much of an option on an airplane, though.

Ruagatr
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Re: Carb Icing

Post by Ruagatr » Thu Jun 21, 2012 7:45 am

That's a well designed system. I have this trouble on the Maddog and that Dominator 1050 gets full of ice in the right conditions. I am going to take a look and check it out. What are the wires hooked to or do they just make circles in the rubber for resistance?

Charles

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Airboat Cowboy Mike
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Re: Carb Icing

Post by Airboat Cowboy Mike » Thu Jun 21, 2012 7:54 am

Put an aluminum six pack holder on carb and leave heat off. If it still ices up might need to go to a 24 can setup.
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lbdb1a
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Re: Carb Icing

Post by lbdb1a » Thu Jun 21, 2012 12:05 pm

I didn't think to try the beer cooler idea. :banghead:

On the performance issue of alternator loading, each 70 watt pad draws about 6 amps for a 12 amp total load @ 140 watts. You can use whatever size pad you want.

I haven't had a chance to run the setup in cold weather but i did a test run on a 92 F degree day on Lake Miccosukee. With the power on to the pads they kept the carb. venturi at the ambient temp of 92 F and the manifold section immediately downstream at 52 F. So we are getting heat energy worth about 40 F into the venturi section in this onetime crude test on a high humidity, hot day.

Each pad has 2 leads, one to ground and the other to the positive battery lead . I connected the 2 ground leads together and grounded it to the engine. I connected the 2 positive leads together and ran it thru a fuse, then to a switch mounted on the console.

After cleaning the surface of paint etc. the Silicon pads are mounted using high temp silicon adhesive.

Larry
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JT122
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Re: Carb Icing

Post by JT122 » Thu Jun 21, 2012 5:36 pm

Where can you buy those from? I would like to get that also.
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Airboat Cowboy Mike
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Re: Carb Icing

Post by Airboat Cowboy Mike » Thu Jun 21, 2012 5:47 pm

That looks pretty good...What about a heat tube from exhaust to supplement the unit under severe conditions.
The Gig is Up..."Mister Toads Wild Slide" .. 300 HP IO-520-D, 74" Whispertip, SS Rigging, 13'6" x 8' Alumitech 4 seat Custom Step Hull, GPS, 4 person Intercom, trolling motor with flounder lights. Odd things on the back and bottom

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Re: Carb Icing

Post by Ruagatr » Thu Jun 21, 2012 7:02 pm

Here is a link I found.

Www.padheaters.com

Maddog

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Re: Carb Icing

Post by todd glover » Thu Jun 21, 2012 7:12 pm

is this fla or alaska ive never seen a carb ice up at sea level are you saying its sweating or getting water on the outside or ice where it wont work

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Re: Carb Icing

Post by Ruagatr » Thu Jun 21, 2012 7:17 pm

Todd i have had many carbs on my car motor boats iceup in either very high humidity or cold and say 60 percent humidity. I amtalking about losing serious rpm and wont stay running at idle until the ice melts.

Maddog

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Re: Carb Icing

Post by todd glover » Thu Jun 21, 2012 7:37 pm

i believe you i just havent ever seen it just thought it was strange

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lbdb1a
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Re: Carb Icing

Post by lbdb1a » Thu Jun 21, 2012 10:46 pm

At Lake Okeechobee last duck season on a cold 35 F humid morning i starting losing rpm due to carb icing. The carb was covered with ice. The moisture in the air and fuel will freeze and build up on the venturi section and throttle plate. This restricts the air flow and causes an over rich condition, thus a power loss can occur.

This explains carb icing pretty well :
CARB ICE
A topic we tend to dismiss in hot weather is carburetor icing. Humid air is plentiful in the summer, and temperatures inside the carburetor can drop 30 to 40 degrees. Summer or early fall are not the times to forget "carb ice." No matter how many hours we have logged, that "carb ice" gremlin can sneak up and catch us by surprise. Engine runup on the ground is by far a better place to discover it than during flight. But many times it is during flight that carb ice rears its ugly head. And when it happens it may have progressed to the point where the only way is down; that is, an immediate landing with little or no available engine power. But first, let's review this ever-present problem, look at means of detection, and share some timely methods for staying ahead of engine icing problems.


What is Carb Ice and What Causes it?

There is always some degree of moisture (humidity) in the air that flows into and through an aircraft engine for every unit of fuel burned. A carburetor provides the explosive air/fuel mixture to each cylinder in the engine, where your power is generated.

As air is drawn into the small throat of a carburetor, the venturi effect accelerates the air and cools it. It cools even further when mixed with vaporized fuel. When this moist air reaches the freezing level of 32°F, the ice particles that begin to form deposit themselves on the throttle plate. The carburetor can then become choked up by this ice to the point that the engine receives less air than is required for full power. The once-explosive air/fuel mixture becomes so rich from excess fuel that the engine ceases to fire.

What Conditions are Conducive to Carb Icing?
Basically: Whenever the cooling effect of the air flowing through the carburetor is sufficient to bring the temperature of the carburetor throat down to 32¼F or colder AND there is sufficient moisture in the air.

Specifically:

If the outside air temperature (OAT) is between about 20¼F and 30¼F with visible moisture or high humidity If the relative humidity of the outside air is high, even in a cloudless sky, with an OAT as low at 15¼F and as high as 100¼F In the spring and fall, especially just after a rain In other words, carbureted engines are susceptible to icing almost anytime.


This where i buy my heating pads. Good prices and fast shipping.

http://www.willrodgers.info/index.html

Larry

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lbdb1a
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Re: Carb Icing

Post by lbdb1a » Thu Jun 21, 2012 11:57 pm

This is a better link to the Will Rodgers heat pads.

http://www.blujay.comT/?page=profile&pr ... bikemagic2

I also installed pads on the oil pan to preheat the oil on cold mornings. I use a timer to run the 120 volt pad to heat the oil to about 160 F . I also use a 12 volt pad if i have no power available.

Cold morning starts with Aeroshell 100W is not a good thing. I know i could use 20w-50 but i just stay with thwe 100w.

Anyway just a thought on how to protect our engines...doesn't cost much to do it right......

Larry
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Re: Carb Icing

Post by GeeLeDouche » Fri Jun 22, 2012 3:25 am

I like this idea. looks good and probably works really well! Thanks for sharing. :)
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akblackdawg
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Re: Carb Icing

Post by akblackdawg » Fri Jun 22, 2012 7:43 pm

Sorry no photo, may post one in next couple days. Older ford v8 motors run a riser about a inch or so think with input and output on it for water. You need to weld up a couple small vaccume line ports to seal it, then hook it up though regular heater hose to the radiator on car motors. Easy to do and stops carb icing in its tracks up here. Best to put a on/off handle so that in summer and not needed you can shut off the heated air for better performance. Be sure and ask if you need more information on this, works good. Bud
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Re: Carb Icing

Post by terrible ted » Fri Jun 22, 2012 8:12 pm

I wish it got that cold to need a solution here.


Cold weather just make a fire and a beer on the river so much better.

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