Need help I’m stumped 031av flooding issue.

[rapozokurt]

That wasn't the question... Did you perform the test?

This makes ZERO sense as well. Extra gas has to be coming from somewhere. Has to be a carb issue.

I checked the new carb after putting it on because of it still flooding and it was level

 

[rapozokurt]

Did you clean and set the gap on the points?

Yes I did

 

[rapozokurt]

I checked the new carb after putting it on because of it still flooding and it was level

That’s why I don’t know what else to look at, both carbs are flooding.

 

[rapozokurt]

Are the gasket and metering diaphrams reversed? That would move the diaphram pin too close to the metering lever resulting in the valve being held open and therefore flooding.

Yes they are in correct order

 

[chilipeppermaniac]

I checked the new carb after putting it on because of it still flooding and it was level

rapozokurt,

As I read through all the posts, I feel like I need to ask a few questions to clarify a few things.

First, we should know what you mean by " flooding?" Do you see raw fuel in the cylinder, spark plug wet, hard starting, can you get it to run with either the original carb or aftermarket one?

Help us understand exactly what the visual or improperly functioning evidence you found that you call flooding.

 

[stihltech]

Sounds to me like your mind is made up it is flooding.
But neither carburetor leaks through.
Eliminate the fuel feed and see if it starts.
Too bad you won't listen to people who worked on these weekly in the 80s.
You have to diagnose and prove it.

 

[rapozokurt]

I checked the new carb after putting it on because of it still flooding and it was

rapozokurt,

As I read through all the posts, I feel like I need to ask a few questions to clarify a few things.

First, we should know what you mean by " flooding?" Do you see raw fuel in the cylinder, spark plug wet, hard starting, can you get it to run with either the original carb or aftermarket one?

Help us understand exactly what the visual or improperly functioning evidence you found that you call flooding.

Spark plug is wet, fires for a split second after I unflood it. Both carbs are doing the same thing. I’m sorry for not giving enough info.

 

[rapozokurt]

Sounds to me like your mind is made up it is flooding.
But neither carburetor leaks through.
Eliminate the fuel feed and see if it starts.
Too bad you won't listen to people who worked on these weekly in the 80s.
You have to diagnose and prove it.

Sounds to me like your mind is made up it is flooding.
But neither carburetor leaks through.
Eliminate the fuel feed and see if it starts.
Too bad you won't listen to people who worked on these weekly in the 80s.
You have to diagnose and prove it.

I am listening that’s why I’m on here looking for any info I can get from people that know a lot more then me.

 

[rapozokurt]

I am listening that’s why I’m on here looking for any info I can get from people that know a lot more then me.

I meant no disrespect brother. I will gather up all what I can and then I’ll head out there tonight and be back with an update if y’all still want to help. Thanks

 

[chilipeppermaniac]

Also, as I think one person mentioned, what is your starting procedure?

 

[rapozokurt]

Also, as I think one person mentioned, what is your starting procedure?

Also, as I think one person mentioned, what is your starting procedure?

Choke a few times then choke off and it usually starts and runs.

 

[chilipeppermaniac]

Spark plug is wet, fires for a split second after I unflood it. Both carbs are doing the same thing. I’m sorry for not giving enough info.

No Need apologize, it is hard to diagnose " over the phone" so to speak. Also hard to know what the exact condition of the SAW, and other components that affect the carb, and vice versa. I've never had or worked on an 031, but I do have some older saws like the 051 and 075. stihltech and others may correct me, but it is entirely possible something other than the carbs is wrong. Also, since you say that you tested both of your carbs and they are assembled, adjusted, pressure tested etc, and yet the saw still floods with both. Either something is wrong with both carbs, or something else is wrong within the saw that is causing or allowing the fuel metering parts within the carb to draw in too much fuel in the times it is supposed to seal or limit the amount of fuel.

I will ask stihltech to hopefully explain this better than I can. I am going by what my 051 shop manual says regarding carb/ fuel delivery, and doing my best to summarize a rather wordy section about how the fuel delivery functions when everything is 100%.

The fuel system section starts by saying that the fuel pump section of the carb functions by pressure in the crank case. This pressure varies with each up and down stroke of the saw's piston. The long and short of it is the diaphragm/ fuel pump parts go up and down inside the carb, they draw in fuel and they close off fuel depending on the pressures. As this is happening, these valves allow fuel to flow to the needle valve. As the operation of the carb is cont. in the section, it mentions how the metering diaphragm is in position of rest when the atmospheric pressure and diaphragm pressures are equal ( the chamber in front of the diaphragm is connected to atmosphere)

As I understand things, much like a float is adjusted in a lawn mower carb, the proper height of the lever that raises and lowers the inlet needle needs to be set right otherwise the fuel will either be too much and could continue to flow too much ( like it on choke when it is supposed to be off choke) or too little fuel. Forgive me if I spoke wrong there. I am trying to not type out the whole fuel section of the shop manual.

I will post this though. It says there are 4 basic operating conditions of the function of the carb

1, Choke valve is closed, and the throttle valve is partly open during the starting process. A powerful vacuum is created in the choke tube during the induction stroke because the entry of outside air is almost completely restricted by the closed choke valve. This means that the engine draws in a large amount of fuel through the jets and relatively little air. A rich starting mixture is obtained in this way. The choke valve must be opened as soon as the engine fires--- the mixture would otherwise be too rich and stall the engine.

 

[chilipeppermaniac]

After I reviewed the fuel section and troubleshooting, I am inclined to suggest a few things that may give us a shot at nailing the issue.

First and foremost, Have you air/ vac leak tested the saw itself?
Also, do you have the carb adjusting tool?

 

[Old2stroke]

There is a possibility that the saw was BADLY flooded at one time and you have not completely unflooded it so regardless of what you do it still seems flooded. Just pulling it over with the plug out will NOT do the job, you have to turn it upside down with the plug hole at the lowest point (ignition off and fuel line off the carb) and pull it over until it stops spraying fuel out of the plug hole then turn it back up to let any fuel caught under the piston drain down, then repeat with it upside down. This will get most of the raw fuel out but not ALL of it, now stick a dry plug in and pull it over a few times, then pull the plug and see if it got wet again. If it did, it is STILL flooded and you have to repeat all the above until the plug stays dry, then try to start with the ignition on and the throttle held wide open. If it doesn't fire after a few pulls, the engine is finally cleaned out and you can squirt a bit of fuel in the carb throat and see if will start and burn that fuel off and the plug should be dry when the engine stops.

 

[oldercut]

what’s up y’all, first time on the forum. I have an 031av that I’ve been working on for months. It has a flooding issue, so I rebuilt the original walbro carb and still floods and the metering level looks perfect. So I bought a dukes aftermarket carb for it, still floods. Has a lot of compression by pulling on it. Impulse line was cracked so I replaced it and it still floods. Took the whole saw apart to pressure test it and no leaks coming for either seal or anywhere. Muffler isn’t clogged up or anything. Has strong spark. Points look new. I’m really frustrated and ready to throw this thing in the rubbish ha. I take the spark plug out and dry it and pull on the cord to unflood it and then try to start it and it runs for a brief 1-2 seconds then floods out.

Hi; I have the same saw although I have another problem right now.
When mine was running, I learned that it was very sensitive to small
changes in the mixture screws. I could always get it running by going
back to the initial mixture settings listed in my manual;
Turn both screws in against the stop; the Main adj. screw 1 1/4 open
( main screw is the one on the left as you face the 2 screws )
Idle or low speed screw 3/4 to 1 turn open

 

[rapozokurt]

There is a possibility that the saw was BADLY flooded at one time and you have not completely unflooded it so regardless of what you do it still seems flooded. Just pulling it over with the plug out will NOT do the job, you have to turn it upside down with the plug hole at the lowest point (ignition off and fuel line off the carb) and pull it over until it stops spraying fuel out of the plug hole then turn it back up to let any fuel caught under the piston drain down, then repeat with it upside down. This will get most of the raw fuel out but not ALL of it, now stick a dry plug in and pull it over a few times, then pull the plug and see if it got wet again. If it did, it is STILL flooded and you have to repeat all the above until the plug stays dry, then try to start with the ignition on and the throttle held wide open. If it doesn't fire after a few pulls, the engine is finally cleaned out and you can squirt a bit of fuel in the carb throat and see if will start and burn that fuel off and the plug should be dry when the engine stops.

 

[rapozokurt]

Come to think of it when I was tilting it fuel was dripping a little out of the impulse hose

 

[rapozokurt]

There is a possibility that the saw was BADLY flooded at one time and you have not completely unflooded it so regardless of what you do it still seems flooded. Just pulling it over with the plug out will NOT do the job, you have to turn it upside down with the plug hole at the lowest point (ignition off and fuel line off the carb) and pull it over until it stops spraying fuel out of the plug hole then turn it back up to let any fuel caught under the piston drain down, then repeat with it upside down. This will get most of the raw fuel out but not ALL of it, now stick a dry plug in and pull it over a few times, then pull the plug and see if it got wet again. If it did, it is STILL flooded and you have to repeat all the above until the plug stays dry, then try to start with the ignition on and the throttle held wide open. If it doesn't fire after a few pulls, the engine is finally cleaned out and you can squirt a bit of fuel in the carb throat and see if will start and burn that fuel off and the plug should be dry when the engine stops.

Come to think of it when I was tilting it fuel was dripping a little from the impulse hose with the carb off.

 

[rapozokurt]

After I reviewed the fuel section and troubleshooting, I am inclined to suggest a few things that may give us a shot at nailing the issue.

First and foremost, Have you air/ vac leak tested the saw itself?
Also, do you have the carb adjusting tool?

Yes I have pressure and vacuum tested it, there’s no leaks anywhere. And yes I have the carb tool.

 

[L34]

Even though it fired once I am not convinced it's firing under compression.