Export thread

Ok so I've been lurking and now I need help. I have a fairly new Poulan Pro with a 14.5 Briggs in it. It doesn't stay running after we stop spraying starting fluid. It'll run forever on starting fluid (if it was cheaper I'd just run that instead of gas :laughing I've never really worked on carbs before so I'll end up with more questions but the carb is clean, it's got plenty of gas in the bowl. Why won't it stay running but won't run on gas? Could the spark plug not be burning hot enough? I just need suggestions and I can check. Thanks in advance.

There is no doubt in my mind you have a clogged carburettor.

Stuck needle valve under the float

I'll take a peek but the Carb is spotless

t.crawford714 said:

I'll take a peek but the Carb is spotless

Click to expand...

It may be spotless outside, but that doesn't say a thing for the interior condition.

Stuck needle valve wouldn't be a dirt thing, They have a rubber style tip and with the new style gas they stick into the needle seat. Time for a new needle valve because it will just keep on happening.

I did pull the Carb off. It is spotless on the inside. No gunk. How do I check to see if it us a stuck needle? What do I do if it is stuck?

Oh, ninja'd. How do I check if it is a needle valve?

t.crawford714 said:

I did pull the Carb off. It is spotless on the inside. No gunk. How do I check to see if it us a stuck needle? What do I do if it is stuck?

Click to expand...

I see what you mean.

Have you checked your fuel filter ? It may be clogged with old fuel if it has been there for a while.

That, or a stuck needle.

Is your fuel pump getting enugh fuel through to the carb?

I am going to put new gas in today. Unfortunately I don't have a new filter. What fuel pump? Aren't mowers just gravity fed?

One of the first things would put a new fuel filter on. you need a in line 1/4 in. low pressure fuel filter from any auto parts store, cheap insurance, change once a year. The fuel pump is next in line from the gas tank. It will have three hoses going to it, in gas, out gas, and a vacuum line. Back to the carburetor needle valve. You will have to remove the carburetor. turn upside down and remove bowl. under that you will see the float, by the float hinge you will see a valve under the float. as you turn the carburetor right side up this valve will move, if not then the needle valve is stock. carburetor right side up you should be able to blow air my mouth throught the carburetor fuel inlet and up side down you should not be able to blow air my mouth throught the fuel inlet and if this is the case your needle valve is working fine.

The needle moves freely with the float and I can blow air in right side up but can't when it's upside down, any other ideas?

Anyone know what kind of spark plug I need for a Briggs 14.5 I/C Quiet? I cleaned the spark plug and it sparks more but I want to check to make sure it's the right one. It may not be burning hot enough to combust the fuel while it would burn the starting fluid.

Do you have a fuel solenoid on the bottom of the carb bowl. If so does it click when you turn on the key. If not then it could be a bad solenoid or stuck plunger. If you don;t have a solenoid then you have a plugged main jet. Could be in the bowl nut, on the side of the emulsion tube inside the bowl, or could be in the nozzle that is screwed into the emulsion tube in the center of the carb under the bowl.

that part of it is good then, maybe float adjustment? is the float level when its up side down? Are you getting a good fuel flow to the carburetor? If it runs on starter fluid only its not getting gas. Have you removed the gas line from the carburetor and turn the mower over with the starter and see if you are getting a good fuel flow. Make sure you have a bottle or can ready to catch this fuel so you don't have a fire. Did you open your air adjustments 1 1/2 to 2 turns out for rough adjustment?

If I don't have the fuel line hooked up on the carb it just flows out of the the line. Any ideas on the spark plug?

t.crawford714 said:

If I don't have the fuel line hooked up on the carb it just flows out of the the line. Any ideas on the spark plug?

Click to expand...

A spark plug is cheap alone with new fuel filter. Take the old ones with you to any auto parts store and they will cross the numbers over for you. less then 10 dollars for the two parts That will ease your mine on that part of it. Just my though is if it runs on starter fluid it should run on gas which cancels out ever thing but fuel. It is hard for me to know what is what other then what you tell me. What you might call clean I might not ?? Does this have a fuel solenoid on the bottom of the carburetor and is it working??

reynoldston said:

A spark plug is cheap alone with new fuel filter. Take the old ones with you to any auto parts store and they will cross the numbers over for you. less then 10 dollars for the two parts That will ease your mine on that part of it. Just my though is if it runs on starter fluid it should run on gas which cancels out ever thing but fuel. It is hard for me to know what is what other then what you tell me. What you might call clean I might not ?? Does this have a fuel solenoid on the bottom of the carburetor and is it working??

Click to expand...

Would that be a little battery looking thing that screws in the bottom of the bowl? If it is, there's no wires going to it.

I should mention that it is a new filter and new gas before I started working on it.

t.crawford714 said:

Would that be a little battery looking thing that screws in the bottom of the bowl? If it is, there's no wires going to it.

I should mention that it is a new filter and new gas before I started working on it.

Click to expand...

That little battery looking thing is called a anti dieseling solenoid. What could well be your problem. When your mower is running you have battery voltage to it opening a valve inside your carburetor and when you turn off your mower it closes so the mower won't keep running at a diesel. You should have a extra wire somewhere that goes to it with battery voltage when the key switch is turned on. Maybe the wire got broken off some how? This solenoid should make a clicking noise as your key switch is turned on and off.

I'm not arguing but why on earth is it called an anti dieseling solenoid? It runs on unleaded 87 haha. I'll check to see if there's a wire that looks like it would touch it, because now that you say that it only passes through the bowl and screws into the carb

t.crawford714 said:

I'm not arguing but why on earth is it called an anti dieseling solenoid? It runs on unleaded 87 haha. I'll check to see if there's a wire that looks like it would touch it, because now that you say that it only passes through the bowl and screws into the carb

Click to expand...

It has nothing to do with the gas type what so ever. The newer mowers for what ever reason, timing, idle speed, engine design?? after the ignition switch is turned off and no more spark at the spark plug the engine will keep running like a very sick diesel engine and that is why it is called a anti dieseling solenoid.

reynoldston said:

It has nothing to do with the gas type what so ever. The newer mowers for what ever reason, timing, idle speed, engine design?? after the ignition switch is turned off and no more spark at the spark plug the engine will keep running like a very sick diesel engine and that is why it is called a anti dieseling solenoid.

Click to expand...

Interesting! :thumbsup:

reynoldston said:

It has nothing to do with the gas type what so ever. The newer mowers for what ever reason, timing, idle speed, engine design?? after the ignition switch is turned off and no more spark at the spark plug the engine will keep running like a very sick diesel engine and that is why it is called a anti dieseling solenoid.

Click to expand...

Ah. So if it wouldn't plug the Carb it would still let fuel in and try to run like a diesel with trying to bust under pressure and a glow plug? That is pretty interesting.

So you're saying that without it being hooked up it's just plugging the Carb?

Yes that's the ant diesel solenoids job plugging the carburetor, but leave the glow plug out. A glow plug in a diesel engine is a electric element that gets hot and heats the compression chamber so it will stat easier.

I have had problems with some engines with the fuel shutoff solenoid. When the electricity is shut off, the spring tension pushes the plunger to shut off the fuel flow. When the ignition is on, the electromagnet is supposed to hold the plunger back letting fuel flow. Sometimes these fuel solenoids have intermittent problems particularly when the system voltage peaks and the engine is hot during a long run time. In one particular design I have had rusty looking silt buildup in the plunger cavity not letting the plunger retract fully and causing reduced fuel flow at high power demand. I have known of some that have cut the plunger off and reinstalling the solenoid with or without the electrical connector plugged in. I also know of some who have removed the solenoid and installed a plug of the correct threads in it's place. I know that these solenoids cost around $100 to replace.
The problem with governed small engines is that when the engine is shut off, the governor will sense the falling RPM and increase the throttle in an attempt to maintain the RPM selected by the throttle lever position. This puts raw fuel into the engine, some of which ends up in a hot muffler and a loud bang from flashing fuel sometimes results. This is one of the reasons for the fuel shutoff solenoid, the other being an emissions issue. Run on of a hot engine as this fuel passes thru sometimes does happen even with a correctly functioning shutoff solenoid.
Mad Mackie in CT:biggrin::laughing:

Well thanks guys! There was a male spade connector that was busted off on the inside. I couldn't get the spade out at the moment but at $100 I don't want to grind down the plunger or replace it. Tomorrow I'm grinding down a bolt to hold the bowl there and to see if it'll work. I'll make a few more attempts at pulling that spade out. I do have to say I'm now the small engines class genius. We have a new teacher that just came out of college and he didn't even know what the problem was.

The anti dieseling solonoid plugs off the main jet.