| reply to chmod
Re: Help troubleshoot snowblower carb problems. You need a new needle valve and seat. |
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 Doctor OldsI Need A Remedy For What's Ailing Me.Premium,VIP
join:2001-04-19
1970 442 W30
kudos:18 | reply to chmod
I'd say the float is too heavy. If it is made from brass then it has likely leaked at the seams and it would have gas inside it, or if it is solid material then the body has absorbed gas making it heavy.
There is a float scale made that is used to determine it's weight.
Tomco Carburetor Float Weight Scale #13700 13.95 + 5.00 shipping
»cgi.ebay.com/ebaymotors/Tomco-Ca···40154759
You can also try local parts stores to get one. You would need to know the correct weight of your float also.
»www.trialspartsusa.com/diagrams/···2000.doc
quote:
The reasons for a float going bad are varied, but I will mention a few of the common problems. Trials machines often sit for long periods and gasoline will eventually permeate the float making it unable to lift the gas needle valve. Some fuels appear to cause premature failure of the float materials. I suspect that the grain alcohol found in some gasoline brands is a common culprit. If a machine is going to be stored for a long period, it is best to drain the fuel from the tank as well as the float bowl. Note: Simply allowing a float to dry may return it to it’s proper weight, however the float remains permeable and must be replaced. If a float (or floats) is bad, the richer mixture coming into the engine will cause poor running. The operator may mistake this problem as being caused by the gas jets. The operator or his/her mechanic may change the gas jets to ones that are “leaner” to compensate for the rich condition. This is not a good solution as the correction only applies to the engine when it is running at low revolutions. As revolutions rise, the carburetor requires more fuel and the engine will quickly use all of the excess gasoline that is in the float bowl.
»www.cheapsnowblowerparts.com/pro···C76.html
quote:
AMF primarily produced lawn equipment under the name Dynamark. This trade name now comes under the Murray corporate banner.
Normally you do not store a gravity fed engine with gas in it, but you run it dry instead before storing it. Alternatively, you can install a fuel shutoff at the tank base.
Regards,
Doctor Olds
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What’s the point of owning a supercar if you can’t scare yourself stupid from time to time? |
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 SplitpairPremium
join:2000-07-29
Cow Towne
kudos:3
1 edit | reply to chmod
said by chmod:The float appears fine, it has no leaks, nor varnish. Is it brass? If so shake it if it's empty it's good if it's composite don't worry about it
What do I look for on the needle? Theres a spring I guess you would call it and I assume is the seat on the bottom side.
Carefully examine it at the tip for any scoring varnish or discoloration.
The seat is the part the needle sets into you may be able to use a bright light and mirror to examine it without removing it from the engine again your looking for any damage or varnish.
If you find discoloration or varnish on either the needle or the seat try removing it with some lacquer thinner and or acetone.
If the needle is damaged it will need to be replaced if the seat is damaged in most cases such as with the Walbro or Nikki carbs the body will need to be replaced as the seat is not removable.
As for parts these folks have great pricing and ship quickly. »www.ordertree.com/
Wayne
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If you cannot fix it with a buttset and some beanies you ain't a technician.
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wbertramPremium
join:2005-08-19
Allentown, PA
3 edits | reply to chmod
Most carbs like this have a fuel bowl with a drain valve on the bottom. If the rubber washer that seals this valve is old, worn, torn, the drain valve will leak.
Locate the drain valve and check the condition of the rubber washer.
You can also drain the bowl using this valve. Then check later and see if there is additional fuel in the bowl. If there is, the float/needle valve are leaking. |
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fixrmanPremium
join:2003-02-10
Hatboro, PA Reviews:
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| reply to chmod
The float is likely sticking or the needle which shuts off fuel flow to the bowl will not seat.
When a gasoline-powered small engine sits for a long period of time, fuel in the bowl dries and solidifies into a varnish. The amount of varnish buildup depends on the amount of fuel present. It is always best to run a lawn mower or other yard tool completely out of fuel before storing. |
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Doctor OldsI Need A Remedy For What's Ailing Me.Premium,VIP
join:2001-04-19
1970 442 W30
kudos:18
1 edit | reply to wbertram
said by wbertram:Most carbs like this have a fuel bowl with a drain valve on the bottom. If the rubber washer that seals this valve is old, worn, torn, the drain valve will leak. Locate the drain valve and check the condition of the rubber washer. Not the issue. Look closely at the image the OP posted. You can see the fuel pouring out of the throat of the carb right by the butterfly valve. The fuel is coming out from the bowl overfilling as fuel keeps coming in past the needle and seat which the OP said that those are good after checking them. That leaves the float having become gas loaded making it heavier than it should be keeping the needle off the seat allowing fuel to flood the bowl and then to flow out the carb throat. Brass or composite floats can both become logged with gas and end up being heavier than they should be which will keep the needle off of its seat allowing the gravity fed fuel bowl to drain the tank as it pours fuel out the carb throat.
said by wbertram:You can also drain the bowl using this valve. Then check later and see if there is additional fuel in the bowl. If there is, the float/needle valve are leaking. Since the bowl is gravity fed, draining the bowl will do nothing as the tank will refill it by gravity when the float drops opening the needle off its seat. Doesn't serve a purpose to drain the bowl when it isn't the problem and it isn't leaking.
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What’s the point of owning a supercar if you can’t scare yourself stupid from time to time? |
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SplitpairPremium
join:2000-07-29
Cow Towne
kudos:3 | reply to Doctor Olds
said by Doctor Olds:You can also try local parts stores to get one. You would need to know the correct weight of your float also.Regards, Doctor Olds Therein lies the problem I have a couple dozen small engine manuals covering most every air cooled engine used in this country since the 70's and in none of them is the weight of the float specified.
FWIW I have rebuilt maybe 100-150 small engine carbs and have never come across found a defective float.
Wayne
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If you cannot fix it with a buttset and some beanies you ain't a technician.
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| reply to chmod
Also check your fuel line. The old rubber breaks down and very small pieces will get between the needle and seat. I've had/seen this problem a few times. Always with OLD fuel lines. From the pictures, yours is painted = original. Hope this helps. jd |
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 PiggieI Actually use WindstreamPremium
join:2005-11-23
Orange Springs, FL | reply to Splitpair
Wayne, I have rebuilt a few dozen carb and have seen one bad float. Normally it's the needle valve.
My general advise is any small engine should have a fuel filter and if gravity feed a cutoff. I add them to any engine I have. I recently bought a Briggs generator. It had a shut off, but not a filter.
I also shut down the engine with the shut off valve if it will be put away for more than a few days. I am sure this cause some lean burning toward the end, but I ride the choke, increasing it to minimize this effect. I don't think this tiny bit of lean running hurts anything and it empties the bowl. I have Briggs engines around here that have run 10 years between carb cleaning or rebuilds doing this.
Another problem I am seeing, a lot of the newer plastic ventless red plastic gas tanks for storing fuel, don't have even a primitive filter in their spouts. They also don't seal very well, as I have found dirt and water in them from being stored outside, that wasn't their before. Sadly I can't find the old style 5 gallon cans I used to buy.
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Doctor OldsI Need A Remedy For What's Ailing Me.Premium,VIP
join:2001-04-19
1970 442 W30
kudos:18 | reply to Splitpair
said by Splitpair:FWIW I have rebuilt maybe 100-150 small engine carbs and have never come across found a defective float. From a Sears riding lawn mower.
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What’s the point of owning a supercar if you can’t scare yourself stupid from time to time? |
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SplitpairPremium
join:2000-07-29
Cow Towne
kudos:3 | No need to put that one on the scale it's fubared that poor float looks like it has been thru World Wars 1 2 and 3 heck it makes my ex look good. 
Wayne
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If you cannot fix it with a buttset and some beanies you ain't a technician.
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SplitpairPremium
join:2000-07-29
Cow Towne
kudos:3 | reply to chmod
The tank may be clean but gasoline is not as such a two dollar inline filter is money well spent and if mounted sideways will trap water.
Wayne
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If you cannot fix it with a buttset and some beanies you ain't a technician.
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 chmodPremium
join:2000-12-12
Lockport, IL | reply to chmod
Good points. I'm going to get an inline filter along with a shut off valve. I will also take it apart again and go over the needle thoroughly. The float is of a composite material, I weighted it down in a bucket of water for 10minutes, took it out and shook it, no holes there.
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Some people are like Slinkies. Not really good for anything, but they still bring a smile to your face when you push them down a flight of stairs. |
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Doctor OldsI Need A Remedy For What's Ailing Me.Premium,VIP
join:2001-04-19
1970 442 W30
kudos:18 | said by chmod: The float is of a composite material, I weighted it down in a bucket of water for 10minutes, took it out and shook it, no holes there. The composite floats are not hollow, they are somewhat solid, but can in some cases absorb gas and then gain weight. Take it out after soaking in gas for over night and then weigh it. Now let it sit out of gas 24 hours to dry out, if it gets lighter then it is bad and if the weight is the same then it is likely good.
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What’s the point of owning a supercar if you can’t scare yourself stupid from time to time? |
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2 edits | reply to chmod
I had a mower do the same thing, older MTD mower using a Briggs & Stratton engine.
The thing is when the mower engine did this on mine the gas seeped into the combustion chamber, past the piston, and on into the mower engine block mixing with the oil. Once the oil was full of fuel then it started flowing back up and out of the carb from the gravity feed of the fuel tank being higher than the engine.
Please be aware that this could have happened to your small engine also as it's a known to do so once the float needle starts allowing fuel through, depending on the orientation of the carb that is.
In my case I changed the float out, replaced the needle, and got some new gaskets for the fuel bell housing on the bottom of my mower along with putting an inline shutoff on the fuel line along with doing an oil change. Since then the mower has run fine for the past 2 summers. |
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chmodPremium
join:2000-12-12
Lockport, IL | reply to chmod
Shut off valve installed, I also bought an inline fuel filter. However with the limited space I have if I installed both a fuel filter and shut off it was to tight a space without crimping. I mocked up different scenarios and even if I shortened up the lines it was getting cut down somewhere because of the small space.
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Some people are like Slinkies. Not really good for anything, but they still bring a smile to your face when you push them down a flight of stairs. |
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 KringleDr.DPremium
join:2004-02-27
Pierrefonds, QC
kudos:3 | Looking good!  |
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 Tursiops_GTechnoidPremium,MVM
join:2002-02-06
Norwalk, CT
1 edit | reply to chmod
Is the clear tubing that you are using suitable for use with Gasoline? otherwise, Gasoline may dissolve it over time...  If it's not, I'd recommend replacing it with a proper piece of Neoprene fuel line...
-Tursiops_G.
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If You're Unsure, "RTFM"... If You're SURE, "RTFM" Anyway. |
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 TA63ST215WPremium,MVM
join:2000-11-23
there
kudos:2 | reply to chmod
Another thing to remember is that, valve or not, you still need to fix the carb.
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Striving for Parfection. |
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