036 Pro goes lean as I cut

[HarleyT]

Well, never been called "tank vent" before....

 

[drf255]

It’s not the vent if I’m reading it correctly. It will stay 4 stroking for 3-4 seconds when you piss rev, then scream?

Your running out of fuel. The metering area is being emptied by the saw and not being refilled fast enough.

Run saw with half tank of fuel and pull the vent. It’s easy enough. See if problem solved.

Next, change fuel line and carb. The Zama that’s on your saw is available AM for around $15 and is the same carb Stihl used. Some of the AM even have “Zama” cast into them. They work just fine. You may need the metering plate and limiters off of your old carb. Replace your line.

I have the same problem you are describing on many 036 I port. They are right on the edge of not enough fuel, so the smallest restriction in fuel flow that didn’t show before porting tends to. For me it’s been the fuel line having a hole in it and/or the carb screen/metering area. The carb is so cheap new that rebuilding it just isnt worth it.

 

[Cantdog]

My bet is the flywheel side crank seal......wimpy little thing down in the bottom of a hole...joy. If you do a pressure and vac test you will likely find it will hold ok under pressure but leak like crazy under vac. This will give you half the problem by letting un metered air into the case causing a lean condition......the other half is that this can give the carb a really wonky pulse signal causing an inability to pump fuel correctly or at the rate needed at speed giving you the other half of the problem of enough fuel to run at idle but not enough for sustained WOT. Of course there are many additional things to check like the impulse line itself, intake boot, fuel line/filter etc.

Solution:.....myself I would do a pressure/vac test to make sure nothing else is leaking then replace the flywheel side seal, impulse line and fuel line as this saw has some years on it even if is low hour....rubber goes to hell sitting as fast as it does in use. Clean and kit the carb...make certain your intake boot is tight and shows no sign of cracking. Use only OEM Stihl rubber parts. There is no savings in fixing only part of the problem enough to get it running again as another problem will soon make itself known. Then go cut wood and be happy as your saw motor will now be in good order for quite some time.

 

[rd35]

Hey guys thanks for all the responses! I may not be able to start in on fixing this saw for a while. But when I do i’ll Report back on what I find. I acquired this saw as the very first in my “collection “! Right after I got it I did my very first carb rebuild on it. So......it may not be assembled correctly. We’ll see!

 

[abramj]

Hey guys thanks for all the responses! I may not be able to start in on fixing this saw for a while. But when I do i’ll Report back on what I find. I acquired this saw as the very first in my “collection “! Right after I got it I did my very first carb rebuild on it. So......it may not be assembled correctly. We’ll see!

You could bring it to me and I will fix it...

It might look like a super XL when you get it back. [emoji849][emoji477][emoji848]

Sent from my MotoG3 using Tapatalk

 

[alexcagle]

Moon pie
View attachment 609115

 

[alexcagle]

@Westboastfaller ..... I'm not quite sure about your long distance chainsaw diagnosis gambling odds.

 

[rd35]

You could bring it to me and I will fix it...

It might look like a super XL when you get it back. [emoji849][emoji477][emoji848]

Sent from my MotoG3 using Tapatalk

HMMM.....Think I’ll pass on that one!
LOL

 

[albert]

My bet is the flywheel side crank seal......wimpy little thing down in the bottom of a hole...joy. If you do a pressure and vac test you will likely find it will hold ok under pressure but leak like crazy under vac. This will give you half the problem by letting un metered air into the case causing a lean condition......the other half is that this can give the carb a really wonky pulse signal causing an inability to pump fuel correctly or at the rate needed at speed giving you the other half of the problem of enough fuel to run at idle but not enough for sustained WOT. Of course there are many additional things to check like the impulse line itself, intake boot, fuel line/filter etc.

Solution:.....myself I would do a pressure/vac test to make sure nothing else is leaking then replace the flywheel side seal, impulse line and fuel line as this saw has some years on it even if is low hour....rubber goes to hell sitting as fast as it does in use. Clean and kit the carb...make certain your intake boot is tight and shows no sign of cracking. Use only OEM Stihl rubber parts. There is no savings in fixing only part of the problem enough to get it running again as another problem will soon make itself known. Then go cut wood and be happy as your saw motor will now be in good order for quite some time.

You beat me to it, great call. Have seen this many times.

 

[Cantdog]

You beat me to it, great call. Have seen this many times.

Yep...me too...most every Stihl that arrives here needs that seal.....026, 034, 034 Super 036.....most are low hour, older saws in good condition other than time has run out on the rubber stuff...if not attended to and continued to run will end with a toasted piston at the very least...