HELP! Where to start with a saw that's been sitting.

[Paul Lloyd-Jones]

So, say a chainsaw was set aside because of a non-engine issue and then it went untouched for a long time. Now it's time to try to get it going again. What do you do first? Do you drain the fuel and start with fresh if it's been sitting about 6 months? a year? 2 years? Does it make a difference if it only ever had non-ethanol fuel used in it? Is there a fuel additive you can use to avoid starting with cleaning the carb? I just got an ultrasonic cleaner, so I am excited to try it for cleaning carburetors, but when is that likely necessary? What would I need to take apart on the carb before putting it in the cleaner? What on the carb would you clean/take apart if you didn't have the ultrasonic?
What if you don't actually know any history of why the chainsaw was laid aside? What diagnostic tools do you guys think every chainsaw mechanic should have handy?
If there are any good videos on this, I'd definitely appreciate a link.
I know this is very broad, and I don't need every one of these questions answered, obviously. But, I'm interested to hear your process. I'm trying to get a clue.

P.S Was this the ideal forum to post this type of thread?

 

[hacskaroly]

I tend to do a general look around and actuate all the parts that are supposed to move. Do they all work without undue resistance, does the recoil recoil...etc? I would dump the fuel (especially if you didn't put it in there) you don't know what all might be in it or what the mix ratio is. You can pull the spark plug out and ground it and see if it has spark. Pull the muffler off to check the exhaust side of the piston. If all looks good and it has spark, you can try new fuel and see if it goes.

As for the carb, if you are going to put it in the ultrasonic cleaner, you will need to take it apart, you do not want the gaskets and diaphragms to go in the solution and it will make it easier for all the dirty bits to come out and settle in the bottom of the tank. Since you have the carb apart, might be worthwhile to just put a new gasket/diaphragm kit in it unless the old ones are still in really good shape.

Don't be afraid to take the unit apart to give it a good cleaning, most time I will take it apart, but not split the case and give it a good cleaning. This gives you time to inspect areas you normally cannot see when the unit is together. This is a good way to find cracked hoses or other parts which may need to be replaced. Here you get familiar with the saw and if you have to do a tear-down later it will already be familiar to you.

What if you don't actually know any history of why the chainsaw was laid aside? What diagnostic tools do you guys think every chainsaw mechanic should have handy?

I think the best diagnostic tools will be your eyeballs, but being able to pressure test the carb and cylinder are very helpful too to find air-leaks. Tachometer will also help with tuning the carb if you don't yet have an ear for it like me. You may need a specific tool to get the clutch off (some take sockets others take specific wrenches) and maybe a flywheel puller, but sometimes you can get this off with just a hammer (many YouTube videos on this.

Good luck, have fun and learn something!

 

[Paul Lloyd-Jones]

Thank you, @hacskaroly! That's helpful. Can you recommend a particular pressure gauge or type? Pressure testing the
"carb and cylinder" is two different things right? I've seen the little gauge that screws into the spark plug hole, but do you need multiple sizes? What do you use to pressure test a carb?

 

[hacskaroly]

Can you recommend a particular pressure gauge or type?

Here is the link to the one I got, it is relatively cheap, there are others that are around $80-100 that people really like:

Amazon - Carb Leak Detector

You can use the same tester for both the carb and cylinder (but yes, two different procedures), however you will need different adapters to seal off the cylinder (intake and exhaust). There are a couple of different spark plug sizes used, so you will need an adapter that will fit. Some people modify an old spark plug and go that route. There are lots of videos on YouTube that show people testing carbs and cylinders.

 

[Kiwioilboiler]

I vote MityVac for the tool I dithered the longest over, but now would not want to be without.

Next would be my mattyo the dentist case tool, but that's for another level of saw play.

 

[heimannm]

Depending on your local wildlife, it may be a good idea to pull the muffler and insure things are in order. In many locations mud daubers like to build nests in empty saws.

Mark

 

[pbillyi69]

i am in the clean it and look at it camp. first then put some new gas in it and see if it will start. of course it also depends on how long it has been sitting. if its been several years thats a far different story. but six months to a year. clean it and try it.
edit was spelling

 

[mrxlh]

Depending on your local wildlife, it may be a good idea to pull the muffler and insure things are in order. In many locations mud daubers like to build nests in empty saws.

Mark

Any saw that has been sitting it’s a good idea to pull the muffler before trying to start it and clean/blow it out. Rust is just as bad or worse than dirt robbers.

 

[Ketchup]

Check fuel tank first. Dump old fuel into a clear container. Does it smell sweet? Does a water layer settle to the bottom? (Both are signs of ethanol). What do the filter and fuel line look like?
If that all checks out the carb internals probably are fine. It might be okay to pour in fresh mix and try a hot cycle.
If not, the carb probably needs new diaphragms and you need new fuel and pulse lines.
DO NOT put the carb in a USC. Walbro put out a bulletin several years ago about USC’s damaging the main nozzle on many carbs. Other brands with mechanical/rubber check valve style nozzles probably have similar sensitivity.

Other things to look for are clogged muffler and magnesium case corrosion behind clutch cover and bottom of case (white/grey powder kinda like car battery corrosion). Also worth checking the condition of the chain and bar sprocket (Rust? Hardened bar lube? Dirt/sand/metal shavings glued to B&C?). Are the tank caps leaking? Is the air filter packed with fossilized dust?

That’s all assuming the saw was a running saw in fair condition when it was put down. If it’s unknown, I would definitely pull the muffler and look at the piston and cylinder walls through the exhaust port. I do that routinely on many saws.

If you see scoring or gray streaks, or if you start the saw and it races despite tuning attempts, then you need a pressure/vac test. Look it up on YouTube.

Tools you’ll want for chainsaws:
PPE-Eyes! Ears!
Screnches
Chain files
Air compressor
Nice-ish set of screwdrivers
Mity-Vac and spray bottle
Hemastats
Needle picks (I use a 90degree machinist scribe)
T-20, T-25, T-27 Torx T-Handles
Metric Hex T-Handles
Light power battery impact with m4 hex and t-27 long bits
Basic 6 point sockets in metric, then SAE, select deep wells
Flashlight
Tachometer
Compression tester
Rags, Brake cleaner, nitrile gloves
Parts containers

You don’t need it all at once, but eventually…

 

[Paul Lloyd-Jones]

Wow, guys! Thanks so much. All this is very helpful.
@Ketchup, that is a very thorough response and list! I really, really appreciate the time and effort you put into that.
I have most of those simple things, but I definitely be looking to pick up some of the more complex tools.

That’s a bummer about the USC and carburetors. That’s the main thing I thought I was going to be using that for. But I’m really glad to know!

 

[drf256]

Personally, I’d pull the muffler and check the piston and muff.

Dump, fill with new fuel, and then a bit down the carb bore. Then just run it. You could be lucky.

 

[David Boyd]

I disagree with Ketchups advice on USCs

I have not seen the Walbro bulletin, but have run many carbs thru a USC and I think it is the single best tool for cleaning hidden passages in carbs. You don't need solvent, just dish soap, plus the heat and vibration of the USC. You do need to remove all the screws and needles so the vibration can get to all the hidden passages. I have had carbs that looked spotless inside emits clouds of grey residue once the USC started working.

Have used a USC to bring an outboard motor (Yamaha 50 2 stroke) back to life after the dealer said he couldn't fix it.
Same with $1,000 generator.
I trust my firsthand experience far more than someone's bulletin.

 

[Woodwackr]

I disagree with Ketchups advice on USCs

I have not seen the Walbro bulletin, but have run many carbs thru a USC and I think it is the single best tool for cleaning hidden passages in carbs. You don't need solvent, just dish soap, plus the heat and vibration of the USC. You do need to remove all the screws and needles so the vibration can get to all the hidden passages. I have had carbs that looked spotless inside emits clouds of grey residue once the USC started working.

Have used a USC to bring an outboard motor (Yamaha 50 2 stroke) back to life after the dealer said he couldn't fix it.
Same with $1,000 generator.
I trust my firsthand experience far more than someone's bulletin.

I agree. Small rubber parts don't seem to have a problem with limited exposure in my experience. My small HF tank is what I use and it has 4min cycles of which I run 2 for carbs, in Berryman's , no more. Now, compressed air into the passages...especially the check valves...yea, no bueno.

 

[Ketchup]

I disagree with Ketchups advice on USCs

I have not seen the Walbro bulletin, but have run many carbs thru a USC and I think it is the single best tool for cleaning hidden passages in carbs. You don't need solvent, just dish soap, plus the heat and vibration of the USC. You do need to remove all the screws and needles so the vibration can get to all the hidden passages. I have had carbs that looked spotless inside emits clouds of grey residue once the USC started working.

Have used a USC to bring an outboard motor (Yamaha 50 2 stroke) back to life after the dealer said he couldn't fix it.
Same with $1,000 generator.
I trust my firsthand experience far more than someone's bulletin.

The bulletin is only for Walbro, so who knows? I’m pretty sure I killed the main jet in several WT 194 carbs using a USC.
But if a USC seems like the only way to loosen the crud, you should be able to drive the jet out before cleaning.

Many other uses for a USC as well.

 

[Sawponder]

Usually remove the ignition from saw, cover the openings, and use compressed air to shoot a liquid degreaser to help clean off debris. Usually dont ever just go in and take the topend off of an older saw, because then debris can easily fall into your bottom end. But if its a newer saw, that hasnt sat for years on end, i do sometimes toss a bit of fuel in the gas tank (if its clean enough in there) and try to fire her up

 

[Motorka]

I just dissemble everything clean and make a list of what it need. Usually new rubber hoses piston ring starter rope ...

 

[lumbersystem]

I just dissemble everything clean and make a list of what it need. Usually new rubber hoses piston ring starter rope ...

That is what I would do. Full disassembly, wear crackdown, and reassembly.
=
A good idea after reassembly is to check everything over, intake hose leaks are costly in time.