Stihl 032AV Fuel Starvation

[rchrdm]

I have an early 1980s Stihl 032AV that I would like to keep running. It still has good compression. It had frequent use the first five years and since then, only intermittent use.

I noticed a lack of power when cutting and cleaned the air filter and put in fresh fuel. It did not help. I took it to a small engine guy for help.

He said there seems to be fuel starvation at high RPM. He replaced the fuel filter and it improved it a little. He thinks a carburetor replacement may be needed. He also mentioned the main crankshaft seal could be leaking air, but that is just a guess.

He said the Chinese replacement carburetors are not good. Is this true? I am having trouble finding a Stihl carburator. Does anyone know of a source?

Am I on the right track here?

 

[rchrdm]

Update: I found an "OEM" carburetor on eBay for about $70 and ordered it.

 

[Gumneck]

@rchrdm Did you open both sides of the carb to see the condition of the diaphragms?

 

[rchrdm]

Thanks. I have not done that yet.

 

[stihltech]

Take a good look at the fuel hoses and vent in the fuel cap. The hose is a 3 piece design. There may be an air leak at the tank connection. The libe in the tank may pinch off under vacuum, or when the carburetor is asking for more fuel. I have also seen the hose from the tank to the carb kink if too long or routed incorrectly.
And yes, do a vacuum and pressure test on the motor. Pulse hose and intake manifold on that old a saw are prone to cracking.

 

[James Sawyer]

I agree a pressure/vacuum test is needed, that's an older saw and you want to know if you have a leak before damage occurs to your saw. I have 034 and 038 both good saws. bet the problem is as stated by stihltech impulse line, seals or Carburetor diaphragm. That old of saw probably not bad idea to replace the seals, impulse line, diaphragm anyway. I'd won't buy the Ebay carb... just rebuild your carburetor you have with OEM parts, make sure you keep the diaphragm and gasket in order... you can buy metering tool for a couple bucks from https://www.farmertec.com/Carburetor-Adjusting-Tools-c3058.html. Seals are easy to replace you can buy tool to pull the flywheel from Farmertec as well, piece of rope (make sure the piston is up above the exhaust port). Just pay attention to the original seal set depth before pulling them, set the seals the same as the original. Lots of YouTube video on how to do all this. Got warn you when you start working on your own saws it can get addicting. You can replace these parts for less than the Ebay Carburetor. If you can hold the saw by the rope without it turning over probable worth fixing. Oh make sure you clean and blow out your saw before taking it apart.

 

[Gumneck]

Thanks. I have not done that yet.

If you bought that saw in the eighties(not sure if you did or not as your post just says "an early 80's saw") or when you may have bought it but if you haven't opened up the carb to see the condition of the diaphragms on both sides I think you will find your answer when you do look.

 

[rchrdm]

Thanks for all the information! I will have a new carburetor soon, if needed. Meanwhile, I'll take a look at the carburetor diaphragms. The saw does not move when I suspend it by the pull starter rope. In fact, it can be a hard pull to get it to turn over to start.

I will report back.

 

[rchrdm]

Where can I get original Stihl parts? I looked online and the sources seem to be on eBay.

 

[irhunter]

I took it to a small engine guy for help.

He also mentioned the main crankshaft seal could be leaking air, but that is just a guess.

Any small engine guy who says the above without saying "you need to pressure and vac test the case" should be avoided.

Yes...new Stihl parts are generally only available from a dealer...not on line.

There is a good chance that if your problem was the carb, the current carb can easily be rebuilt by you for <20 bucks. What carb does it have?

Roy

 

[rchrdm]

Thanks. I am familiar with a compression test, but what tool do you use to do both a compression and vacuum test? The saw seems to lots of compression, judging by pulling on the starter.

 

[irhunter]

Case pressure and vacuum test is different than compression. One does the case pressure and vac test to detect seal-, gasket-, and-such-, leaks:



Case leaks produce lean-running conditions which can result in over-heat and melted pistons.

Roy

 

[rchrdm]

I put a new carburetor on the saw yesterday and it works fine now! Need to tweak the fast and slow carburetor settings.

Does anyone know of a downloadable service manual for this saw?

Richard

 

[irhunter]

Does anyone know of a downloadable service manual for this saw?

Richard

I have one...but, this site says the file is too large to attach to a PM. You can send me your email in a PM and I will send the manual.

Or, try the Beg for Manuals thread.

Roy

 

[ray benson]

I put a new carburetor on the saw yesterday and it works fine now! Need to tweak the fast and slow carburetor settings.

Does anyone know of a downloadable service manual for this saw?

Richard

Check your inbox for an ipl and a mediafire link to the service manual