Troy Built 17.5 horse carb problem


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Old 01-12-08, 01:56 PM
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Troy Built 17.5 horse carb problem

I have a Troy built rider with a 17.5 horse Briggs engine. I got it at an estate sale, and the mower had been sitting for a year or so. It will run only if I continually spray gas into the air intake of the carb. It has plenty of gas getting to the bowl, and I have taken it apart and cleaned it twice. I could not find any deposits, the float and needle valve appear to move freely. I blew out all of the ports with carb cleaner, and still it will not run on its on. Where most bowls have a drain plug this one has a electrical solinoid that seems to work, when I turn the key on I can here it retract the plunger. Any suggestions?
 

Last edited by hayniea7; 01-12-08 at 02:28 PM.
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Old 01-12-08, 09:18 PM
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You still have a carburetor problem. Did you soak the carb in a bath type cleaner? Also, use a torch tip cleaner from a welding shop to clean each jet and orfice you see.
 
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Old 01-12-08, 09:48 PM
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Cheese is right. Get a bath type cleaner & soak the carb & with a new kit & float, put it back together & adjust it & you'll be as good as new, or better!!!!Is this the updraft carb on this unit?? Roger
 
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Old 01-13-08, 10:50 AM
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Originally Posted by hopkinsr2
Cheese is right. Get a bath type cleaner & soak the carb & with a new kit & float, put it back together & adjust it & you'll be as good as new, or better!!!!Is this the updraft carb on this unit?? Roger
Not sure what you mean by updraft so I am just guessing here, the fuel supply and bowl are on the lowest point of the carb and the air supply comes from the right side of the carb and exits on the left with the air fuel mixture, so the fuel is drawn up if that is waht you are asking
 
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Old 01-13-08, 08:46 PM
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If you could post some engine I.D. numbers, the guys will know what you have & we can be more help. You still have a blockage in the carb, now to find out what carb you have...Thanks, Roger
 
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Old 01-13-08, 11:24 PM
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A little quick trick that often works for me when I'm pretty certain that the carb on any small engine has an obstuction in one of the jets or pick-up passages (and it appears that the engine has been idle for a period of time):

If the unit has an electric starter firmly press the palm of your hand over the throat of the carbuerator (you will have had to remove the air cleaner and any other obstructions to do this) and crank the engine for a minute or so. You should feel the vacuum created by the intake stroke trying to suck your palm into the throat (you can even feel it pulsing in time with the downstroke of the piston if you pay attention) . What you are doing is starving the carb of one of the two things it mixes - namely the air. Consequently all the negative pressure is concentrated on the fuel lines.

Use no ether and do not prime the carb prior to this prodecure.

After a good long crank, you can then remove your hand and check for evidence of fuel in the carb. Often times this check will actually clear the obstrction and let fuel begin to flow. Not exactly the text book method but it does work in many cases (mostly that jellied gas/varnish type of blockage).

Still no fuel after that step? Try the same basic theory but in the opposite direction:

Valve off the fuel tank from the supply line that leads to the carb ( should be a little plug valve under the tank).

Remove the gas line from the down stream (outlet) side of the valve. Get a sports drink bottle (those squeeze bottles with a straw) fill it with gas and insert the straw into the opening of the gas line that feeds the carb.

It sounds as if you are familiar with how the bowl float mechanism operates so it is best if you initially either remove or disable the float.

Squeeze the bottle firmly and try to dectect whether gas is being pumped through the carb and into the intake (cranking the engine and holding your palm over the throat will also increase the pressure differential and intensify the effect).

These methods are about all you can do, other than - as the others have suggested - mechanically cleaning the jets with a tiny piece of copper wire.

One last resort is to remove the carb and try to "blow back" through the passages with compressed air. But you need to pull the carbuerator to do this anyway, so you might as well run a wire through every brass insert that you see while it is open.

By the way (and I probably should have started with this), it is best to do these procedures with the plug wire pulled. Like I said they often work and if they do the engine will start up unexpectedly.

One last thought;

You state that the bowl has some type of solenoid acuated drain valve installed where the drain plug would normally be screwed in. Why not remove the valve and temporarily replace it with a plug - there is a chance that you are sucking air in through the valve.

These little plastic valves will often leak in one direction and yet not the other. In other words it may be allowing air in but still not be showing any evidence of gas leakage out.

Also, if you do the squeeze bottle thing, take a good look around for evidence of gas leaks. A leak in the fuel system that allows gas to leak out while under pressure will many times allow air to be drawn in while under vacuum.
 
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Old 01-14-08, 04:12 AM
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Originally Posted by hopkinsr2
If you could post some engine I.D. numbers, the guys will know what you have & we can be more help. You still have a blockage in the carb, now to find out what carb you have...Thanks, Roger

17.5 horse Briggs Model# 316707 Type#0154 E1 Code#041129ZE Walbro carb part # 793224
 
 

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