Customer comes in and asked me a tough one.

[Rockjock]

Gentlemen today I had a customer come in and pick my brain as to what is the matter with his saw. He has a Ms 460 that he purchased recently. The saw was checked out and he was told it was fine. ( servicing dealer stated this ) Well he has issues starting it so he removed the limiter caps, reset the H and L to factory settings 1 turn out and the saw would fire on the 3rd pull , then fast idle but in run it would just die. He tells me he adjusted the LA and it made no difference. He put the saw on his bench and went in to have dinner. Well he comes out and absent minded adjusts the saw again 1 more turn to H and L ( now 2 full turns out ) and the saw fires up on the 3rd pull, then fast idle and then it runs as it should. Acceleration is crisp BUT the LA screw has little affect for the idle. ( runs at about 2800-3k 2500 is spec IIRC ) well he lets the saw sit over night and it fires on the 3rd pull.. fast idle then runs .. be it a little quick idle wise and the chain creeps a bit. He looks at me and asked sooo what ya think? I said well.. I am thinking carb kit, maybe a leaky seal or a bad carb ( had an 026 that acted exactly the same way and it was the carb that was the issue ) What say you fine gents?

 

[HarleyT]

What did he have for dinner?

 

[Rockjock]

What did he have for dinner?

Funny you should ask Moose. He is a hunter and was showing me all these pics.. Pretty handy guy as well so its a perplexing problem.. what think you rottie with a cigar?

 

[HarleyT]

Either way, going through the carb/fuel system would be the first step.

 

[HarleyT]

 

[Ted Jenkins]

For sure the carb along with the gaskets as a start. If the same symptoms come up then of course go deeper, but my guess is what ever the issue is it will become more evident after carb surgery. Thanks

 

[Stihldoc]

REALLLLY......?
Lets open up the patient because it makes the most sense. Really? No, not at all.
Sure, its possible that the carb, fuel hose, or fuel filter could be the cause, but isn't that a lot of work to do without any testing? Pressure and vac test the crankcase BEFORE doing any repairs based on guesses. When the P&V test is done, the results will rule out or rule in where you should go next.

 

[HarleyT]

REALLLLY......?
Lets open up the patient because it makes the most sense. Really? No, not at all.
Sure, its possible that the carb, fuel hose, or fuel filter could be the cause, but isn't that a lot of work to do without any testing? Pressure and vac test the crankcase BEFORE doing any repairs based on guesses. When the P&V test is done, the results will rule out or rule in where you should go next.

Interesting....

 

[Rockjock]

REALLLLY......?
Lets open up the patient because it makes the most sense. Really? No, not at all.
Sure, its possible that the carb, fuel hose, or fuel filter could be the cause, but isn't that a lot of work to do without any testing? Pressure and vac test the crankcase BEFORE doing any repairs based on guesses. When the P&V test is done, the results will rule out or rule in where you should go next.

Good point but the saw will need a carb kit anyway and at a labor rate of 95/hr... I am sure he will opt for the carb kit. If it was my personal saw then yes I would do just that. for now he is in cheap mode.

 

[lone wolf]

Good point but the saw will need a carb kit anyway and at a labor rate of 95/hr... I am sure he will opt for the carb kit. If it was my personal saw then yes I would do just that. for now he is in cheap mode.

If you don't have a known working carb to try on it then pressure vac is the best option. It also gives you a great idea of where to go from there.

 

[HarleyT]

If you don't have a known working carb to try on it then pressure vac is the best option. It also gives you a great idea of where to go from there.

Like through the fuel system?

 

[Conquistador3]

I had an Alpina brushcutter which did that just that. Mind it was one of those cheap Chinese Walbro WT copies (early Ruixing?) so there was just the idle adjustement. Turning it fully in made no difference over half in.
A slightly used carburetor from a straight-gassed unit solved the problem: no point in repairing those cheap units.

 

[Justsaws]

Since you are pulling the carb to do a p/v test, take the couple minutes and poke around in the carb. Then do the p/v test anyhow and charge for the 15 minutes that should take.

Whole thing with a new fuel line, filter and impulse would be done in well under an hour if it passes the p/v test. Unless the saw is dirty, then at least an hour for cleaning up the filth that they carried in.

Clean saw should cost less to fix than a dirty saw, by at least 50%.

 

[alexcagle]

Do the quick, cheap simple things first.......

Dump the fuel in a clear container. Look for water on the bottom, or cloudiness.

Does it smell right? no diesel odor?

I've ran into saws with fuel that didn't have a normal pungent fresh gas odor. A fuel stored in a can that had been stored with no lid can cause this. I think this reduces the fuel's volatility.

While the fuel is out, pull the fuel filter off. Blow it dry, then try to blow through it. Should be relatively easy. - or replace it with a new one if fuel is "icky" to you. Then stick the tester on the fuel pickup hose and test for a slow leak down issue.

Check the flywheel gap for too much clearance.

Go ahead and change the plug. If you find out later that that wasn't the issue, then save it for future use, as a "known good" spare. Lots of people don't know that the crush ring seal only works right if you turn the plug another 90 degrees after first feeling it bottom out. You should feel a second resistance, then stop so you don't strip the aluminum threads out.

Check to see if the symptom persists with the air filter removed.
I've seen some HD filters that looked fine, but the owner cleaned them with paint thinner or something that is oily, instead of lacquer thinner which flows out the oil to leave a dry filter that flows air.

Take the starter off and inspect the intake boot for tears at the clamps from jolts, or overtightening.
Also check the impulse hose for dry rot cracks or pinholes from a sharp stick that accidently got poked in there.

 

[ChoppyChoppy]

Good point but the saw will need a carb kit anyway and at a labor rate of 95/hr... I am sure he will opt for the carb kit. If it was my personal saw then yes I would do just that. for now he is in cheap mode.

Put a new aftermarket carb. We quit putting can kits in stuff carbs are cheap on. It's less headache and cheaper for the customer.

 

[Westboastfaller]

Sounds frozen to me? Cold out side warm shop? Doesn't explain why two turns lean...right? Did it run with Choke on or just fast idle? If carb isn't responsive then it's the carb. If a carb is good you can still change tune with a big air leak has been my experience. That would be way on the fat side ..not clockwise anyway.

 

[Rockjock]

Put a new aftermarket carb. We quit putting can kits in stuff carbs are cheap on. It's less headache and cheaper for the customer.

We do not do aftermarket parts. Stihl does not allow it. Belts and air filters for zero turns and mowers yes. Customer said the saw cuts like a champ but the 2 turns out has me perplexed. He will do a carb kit on it and report back. 130.00 for a carb so lets see!

 

[William Balaska]

Two turns out because it's starving for fuel. Either a vacuum leak or stiff carb diaphragms as,well as the usual fuel and impulse line issue.

 

[ChoppyChoppy]

We do not do aftermarket parts. Stihl does not allow it. Belts and air filters for zero turns and mowers yes. Customer said the saw cuts like a champ but the 2 turns out has me perplexed. He will do a carb kit on it and report back. 130.00 for a carb so lets see!

Maybe different for a Stihl dealer, dunno. $130... or $30 for same carb aftermarket.

 

[HarleyT]

HD-14 costs $75 retail here.