Trouble getting Stihl 032AV to run

[sherka]

Hey there, been on the forum for a while but never made an account, finally I have a problem I can't solve. I have a Stihl 032AV and can't get it to run on its own fuel supply no matter what I do, but if I feed it fuel through a squirt can into the carb it runs perfectly and can rev up amazingly. I've rebuilt the carb, and cleaned it out like 5 times now, even swapping it out with a carb from a fellow 031 I have, still nothing. Took a bit of it apart, checked the impulse line no cracks, put grease on the end of it and turned the engine over and it sucked the grease in. Are there other, more reliable ways to check for vacuum? The air intake boot is also in good condition, I really have no idea what else it could be if it has vacuum and spark, I guess not fuel but the carb is totally fine. The only thing my 032 is missing is this plug thing, no clue what it is or what its called, right next to the impulse line feed on in the images below.




Meanwhile here is the same thing on my 031 that has a metal piece in it. I have no clue what this does and if it would effect my engines ability to run on its own fuel.



Help, advice, and words of wisdom are greatly appreciated, thank you!!

 

[HarleyT]

Here is the part on the ipl in the Mediacat.

 

[HarleyT]

The 031 has the same part number on its valve, so yours is missing its innards.

 

[HarleyT]

While you have it torn down, take a peek at the piston skirt through the intake.

 

[HarleyT]

But with the squirt of gas into the carb to get it to run thing, will it keep running, or dies after the squirt burns off?

 

[sherka]

The 031 has the same part number on its valve, so yours is missing its innards.

Thank you!! Couldn’t find that part for the life of me. After searching it’s an “oil tank valve” so once again I’m stuck… I don’t see why the bar oil valve missing would cause my saw to not run on its own fuel.

Anyone have other ideas as to why it wouldn’t run? Thanks

 

[sherka]

But with the squirt of gas into the carb to get it to run thing, will it keep running, or dies after the squirt burns off?

It won’t keep running, as soon as that fuel burns off it dies out. If I keep manually feeding it fuel it will run amazingly until the squirt bottle is out of gas

 

[sean donato]

The oil tank valve won't affect the saw running in the least.
Are you sure your fuel line/clunk is in good shape with no pin holes?
Fuel pump side of carb is free and clear? Will it fire on the choke?
Metering lever set correctly? You get fuel from the main, transition and idle jets if you spray in the needle holes?

 

[TRTermite]

The Carb From the "FELLOW 031" runs fine on the 031 is assumed. Does your 032 carb run fine on the "Fellow 031" saw?
If yes - then
1- pinpoint between fuel line barb on carb to the fuel in the tank,
2- check for vacuum leaks (grease sucking into impulse is a good sign you are getting impulse to run the carb).
3 If you have a spare purge bulb plumb it into the fuel line to see if the bulb will pull fuel clear of air bubbles, and not lose ?prime? you should incorporate a piece of clear fuel line between original fuel line and purge bulb so any air bubbles are easily seen.
IF NO - then
1- Do the list I mentioned for peace of mind
2- Check that the Carb Gaskets/Metering Diaphragm/Fuel Pump are installed in the proper order.
3- Do as SDonato post #8. ***But the "Fellow 031 carb not working on the 032 saw tends to eliminate carb as the issue (NOTE my use of the word "Tends") and if 032 carb runs well on the 031 the process of elimination "HELPS" "Pinpoint" problem area.

 

[sherka]

The oil tank valve won't affect the saw running in the least.
Are you sure your fuel line/clunk is in good shape with no pin holes?
Fuel pump side of carb is free and clear? Will it fire on the choke?
Metering lever set correctly? You get fuel from the main, transition and idle jets if you spray in the needle holes?

Fuel line is fine, impulse line is fine. It won't fire with choke on or off. Metering level is another subject will continue below

3 If you have a spare purge bulb plumb it into the fuel line to see if the bulb will pull fuel clear of air bubbles, and not lose ?prime? you should incorporate a piece of clear fuel line between original fuel line and purge bulb so any air bubbles are easily seen.

what is a purge bulb, not familiar with that term. I did incorporate clear line running from the tank to the carb and can see that fuel is getting to the carb, no air bubbles or anything.

In the carb the fuel level in one carb didn't move at all, and the other carb the fuel slowly leaked out when pushing on the lever that makes the needle go up. Something i realized with the cheap carb kit I got is that the new parts didn't move the needle up and down that much at all. I bent the arm to allow the needle to raise higher which now lets fuel flow a lot better. Still wouldn't start, video below for reference, except this is the other carb that just didn't drain at a;;
View attachment IMG_1532.MOV

this is the rest of the 031. never saw it run it was disassembled like this when I got it along with this 032.

Took the carb off the 032 and it is obviously pulling fuel in, plenty of it.

 

[scruffy808]

I have an 031 no end of troubles with it. Especially ignition system you cannot get good coils gat match original, causes timing issues. As you say some carby kits don't lift the needle properly when set level with instructions. If you not tried fill tank absolutely full, if it runs then trouble is with tank suction tube/ filter. The pulse line also critical to be 100% sealed.

 

[TRTermite]

Fuel line is fine, impulse line is fine. It won't fire with choke on or off. Metering level is another subject will continue below

what is a purge bulb, not familiar with that term. I did incorporate clear line running from the tank to the carb and can see that fuel is getting to the carb, no air bubbles or anything.

In the carb the fuel level in one carb didn't move at all, and the other carb the fuel slowly leaked out when pushing on the lever that makes the needle go up. Something i realized with the cheap carb kit I got is that the new parts didn't move the needle up and down that much at all. I bent the arm to allow the needle to raise higher which now lets fuel flow a lot better. Still wouldn't start, video below for reference, except this is the other carb that just didn't drain at a;;
View attachment 1027685

View attachment 1027681this is the rest of the 031. never saw it run it was disassembled like this when I got it along with this 032.

Took the carb off the 032 and it is obviously pulling fuel in, plenty of it.View attachment 1027684
View attachment 1027683

So we are not so sure the 031 carb is 100% . A "PURGE BULB" is a nickel buck ninety eight item many refer to as a primer /bulb you will find on many SMALL saws that is a pump/check gadget that is intended to pull fuel mix through the carb and return the fuel to the tank and it is very good at eliminating air out of your system. If you are dead certain your filter/fuel pickup line is good the purge bulb isn't needed but to me eliminating "ALL" problems will help pinpoint the actual issue. Your pic shows mix at the bottom of inlet /screen before it gets to the needle. The needle should take a certain amount of pressure before it is over rode. You said it is obviously "PULLING FUEL IN" . The Fuel is FALLING in not being PUMPED in as per your Picture. The Metering diaphragm needs impulse to actuate the needle arm to open the needle, yet the needle needs to prevent Unwanted fuel from free flowing. If your aftermarket carb kit Has a button that is the wrong dimension the "NO WORKEE" mode over rides the "WORKEE" mode. I have read of this button being the culprit more than a few times.
The metering diaphragm should not contact the needle arm and let the fuel inlet hold several pounds of pressure, then dump the pressure when the impulse triggers it. That is hard to test on these saws due to the impulse mating at the carb body. It has been a while since I worked on one but "THINK" The needle arm should be set flush with the carb body surface the gasket sets on... then the metering diaphragm , then the cover/cap. The Fuel pump goes - Carb Body then the fuel pump then the gasket and then the cover/cap.
Back to post #8 do you get flow through the High and Low jets/ports with the needles out and a shot of carb clean?. These carbs are simple yet the simple issues are what BITES you in the arse.

 

[sean donato]

I have an 031 no end of troubles with it. Especially ignition system you cannot get good coils gat match original, causes timing issues. As you say some carby kits don't lift the needle properly when set level with instructions. If you not tried fill tank absolutely full, if it runs then trouble is with tank suction tube/ filter. The pulse line also critical to be 100% sealed.

I'm not a big fan of them either. My grandads sits on a shelf for sentimental reasons.

 

[sean donato]

So we are not so sure the 031 carb is 100% . A "PURGE BULB" is a nickel buck ninety eight item many refer to as a primer /bulb you will find on many SMALL saws that is a pump/check gadget that is intended to pull fuel mix through the carb and return the fuel to the tank and it is very good at eliminating air out of your system. If you are dead certain your filter/fuel pickup line is good the purge bulb isn't needed but to me eliminating "ALL" problems will help pinpoint the actual issue. Your pic shows mix at the bottom of inlet /screen before it gets to the needle. The needle should take a certain amount of pressure before it is over rode. You said it is obviously "PULLING FUEL IN" . The Fuel is FALLING in not being PUMPED in as per your Picture. The Metering diaphragm needs impulse to actuate the needle arm to open the needle, yet the needle needs to prevent Unwanted fuel from free flowing. If your aftermarket carb kit Has a button that is the wrong dimension the "NO WORKEE" mode over rides the "WORKEE" mode. I have read of this button being the culprit more than a few times.
The metering diaphragm should not contact the needle arm and let the fuel inlet hold several pounds of pressure, then dump the pressure when the impulse triggers it. That is hard to test on these saws due to the impulse mating at the carb body. It has been a while since I worked on one but "THINK" The needle arm should be set flush with the carb body surface the gasket sets on... then the metering diaphragm , then the cover/cap. The Fuel pump goes - Carb Body then the fuel pump then the gasket and then the cover/cap.
Back to post #8 do you get flow through the High and Low jets/ports with the needles out and a shot of carb clean?. These carbs are simple yet the simple issues are what BITES you in the arse.

People are also known to flip the diaphragm gaskets around the wrong way, and or stack then the wrong way as well. We've all done it. It happens.
OP. From everything you say, it pretty much narrows it down to a blockage in the carb, metering lever height issue, impulse issue, or fuel pick up issue.

 

[HarleyT]

Those older saws had a fuel filter made up of several pieces, including a foam insert, that would crumble after 30 years or so, and the crap would pack in the orifices of the carburetor..
I think that you need to go through the carb thoroughly, The passage under the needle needs to be clear, hold it up to a light to confirm. And go back with a new fuel filter, or a new foam insert.

 

[Roygor]

Try replacing the fuel line in the tank. After years, the gas will make them soft and they will collapse from the vacuum.

 

[sherka]

Sorry about the radio silence in my end, was out of town and waiting for an OEM Walbro carb kit to come in, that would have to fix it right? Nope haha, more info down below.

OP. From everything you say, it pretty much narrows it down to a blockage in the carb, metering lever height issue, impulse issue, or fuel pick up issue.

Yes I agree now. Has to be. I think it’s a metering lever height issue. When it runs while I squirt fuel into it, there is plenty of fuel in the carb and getting to the carb. I put in a clear line to watch it move and for air bubbles, ontop of when I tear the carb down and break it open fuel pours out of it.

Those older saws had a fuel filter made up of several pieces, including a foam insert, that would crumble after 30 years or so, and the crap would pack in the orifices of the carburetor..
I think that you need to go through the carb thoroughly, The passage under the needle needs to be clear, hold it up to a light to confirm. And go back with a new fuel filter, or a new foam insert.

I have replaced the fuel filter and all lines, sorry for not mentioning before. The passage has been clean every time I tear the carb apart, I make sure of it.

Try replacing the fuel line in the tank. After years, the gas will make them soft and they will collapse from the vacuum.

Thank you. Did this when I first got the saw a bit ago.


Like I said above I think it’s a metering issue now. With this OEM kit I got, I installed everything and…
wow that’s not right at all, totally recessed. I didn’t bend it at all that’s how it came. Great.

I put the aftermarket one back in and bent it a bit until it was flush with the rest. Now it can move down but doesn’t move the needle much at all to do anything


I don’t really know what to do know. Most of this carb stuff is pretty straight forward besides metering height, I don’t know much about that or how to get the needle to move, also don’t want to be too aggressive with it and allow way too much fuel in. Any advice or help?

Would also just like to say a massive thank you to everyone who contributed to troubleshooting so far, all the different insights into one issue has been majorly helpful when ur comes to narrowing down a problem, thank you all

 

[sean donato]

Pretty sure that model is set the lever flush with the carb body. The needle doesn't really lift off the seat much to begin with. Set it up, toss it on the saw and see what it does.

 

[HarleyT]

That circuit plate cover screw doesn't look right, it should be flat topped.

 

[sean donato]

That circuit plate cover screw doesn't look right, it should be flat topped.

I believe you are correct.