I am not familiar with the Craftsman chainsaws but I am familiar with chainsaws in general.  I would first pull the air filter and make sure it's clean and unobstructed and visually inspect that the choke is opening and closing properly.  Pull the spark plug and inspect it, making sure it is not fouled.  Also make sure the chain is not too tight on the bar.  If you had fuel that sat for an extended amount of time in the tank go ahead and replace with fresh fuel.  Check to see if any of this was helpful before moving on...

Next you can search for leaks in the carb by lightly spraying carb or brake cleaner around the carb and air/fuel lines while the saw idles.  If the throttle spikes you have an air leak somewhere.

Finally, there should be 3 screw adjustments, H, L and Idle (I don't know how Craftsmen labels these and it's probably a good idea to refer to the manual whether it be hard copy or online).  These should be tuned in this order: Idle -> Low Speed Mixture -> High Speed Mixture.  Since I don't know your particular saw, you will need to look up some baselines for this before you start making any adjustments.

I'm certainly no expert nor do I claim to be a engine repair man but I have worked on quite a few small engines with pretty good success.

Good luck! 

KitJ BBQman wrote on 08/01/14 at 6:33pm:


I have found the opposite to be true.  Octane is an ignition retardant and helps engines with high compression ratios avoid knocking/pinging.  Small engines normally have low compression ratios and while they will run on any fuel whether it be 87 or 93, 93 makes them more difficult to start in some cases.

First off, thanks for the replies.  Second before you guys get into a low down drag out debate about fuel, I talked to a mechanic at the local John Deer/Stihl store.  There is something to consider with which fuel you use, but he made the point that its not the octane, its the ethanol in the fuel. He made the point that ethanol is essentially corn sugars & when they sit for too long it separates from the fuel, basically leaving sugar in your tank which in turn gums up the engine. Originally they only added ethanol to the low octane fuel which would have the higher octane better for smaller engines.  Now that they are adding it to both high and low octane neither are great.  He made a point of using a good stabilizer as well as try to find fuel without ethanol. The Shell station on Stallings and Old Monroe have a separate pump for ethanol free fuel. 

Back to my situation- I did most of what you said Sloth before I  posted up here. Took the saw apart, checked air filter, cleaned spark plug (should probably replace) and also sanded the contact points. Also checked the choke and its working fine. There is stabilizer in the fuel but I should probably try replacing that too.

I haven't checked for leaks on the carb. When I moved I dumped my old carb cleaner and haven't replaced it yet... add it to the list.

The point I'm at is making the adjustments on the high/low & idle.  I can tweak the idle but the high/low "knobs" are a star type screw. Problem being its not a typical six point star screw, it looks like a 12-16 point star and of course its within a case that you cannot easily access or use alternate tools.   

Where my lack of small engine knowledge fails me is that if I have it on full choke, and pull, it starts right up and runs idling high to normal.  If I reduce the choke at all, it dies.

Does this tell me anything about the spark plug?  Would it run if the spark plug was foul.   

Does anyone out there have access to the tool I'm describing above?

Solar wrote on 08/02/14 at 2:20pm:


I have a Craftsman too. It is pushing 20 years old. Had the system cleaned a couple times when it acted up over the years. Last fall it did about what yours is doing, only developed fuel leak. Took it to Kannapolis Power (Husky dealer) The ethanol had destroyed the fuel system. They got new parts and got it back to me. $118.00 US. Cheaper than a new saw. Moral is use a stabilizer (Idid) and dodge the ethanol. (I cannot seem to find the right stuff around Kanappolis) As far as the star tool maybe Buffalo Tool or Harbor Freight?

I know you're specifically asking about how to make the carb adjustments and nobody is addressing your question, but I'll join them if you'll permit. I spent a lot of time messing with a gas blower last summer and went through a lot of this process. First thing, as Chosen One said, is to dump the fuel and put fresh in. In the future, always run it dry before storing for an extended period to avoid gumming up the carb. Second, a cheap thing to try is to replace the fuel filter, which is generally down in the fuel tank. You'll have to fish it out with a bent wire. It's on the end of the fuel line and flops around in the tank. If it will only run on choke, then it could be an air leak as someone said requiring more fuel to keep a proper mixture, OR it could be a shortage of fuel coming in to the carb due to a partially clogged fuel filter. If that's it, it's a $3 fix. The last thing is what I finally had to do...take apart the carb and blow it out with an air compressor from the inside toward the fuel intake. I was really hesitant to do that, but had eliminated everything else and was going to put a new carb on it anyway ($45 online) if it didn't work. So that emboldened me. I looked up a diagram on the internet so I knew what to expect and blew back toward the screen from inside the carb toward the intake. The screen got away from me, but I put the carb back together and it ran like new.

KitJ BBQman wrote on 08/01/14 at 6:33pm:



+1

(You need to Login or Register to view media files and links)

Never had a problem.

I add it to my gas can, so it's always on board.

As for the tune up, the only option there besides doing it yourself is to take it to another shop and get it checked out. In my experience, 99% of the time if you've got a small engine problem it's the gas. Drain it and refill it.

Solar, I'm not a chainsaw technician but I was a mechanic in a motorcycle dealership for over 25 years and have worked on my share of chainsaws, weed eaters, and such.  There has been lots of good information given and I will add one additional thing to look for.  I'm not sure about your craftsman but most of the chainsaws have a vacuum line running from the cylinder to the carburetor that operates the fuel pump.  My experience has been that over time this line dry rots and cracks causing an air leak.  The hose is very small and sometimes specific to that saw.  Most husky's now require a specific part to replace the vacuum line.  So yours may or may not require a specific part.  Also most times when the engine will not run without the choke after sitting for weeks and months it is an indication that the pilot circuit in the carburetor is stopped up.  So a disassembly and cleaning would be in order, then fresh premix.  The airbox lid should not be an issue.  I'm not sure where you are located but I live just a couple of blocks from Rocky River Trail if you want some assistance. Send me a pm or email if you're close and want to bring it by or I can send you my cell number.

Lester

Also be careful running the saw out of gas because a 2-cycle engine requires the oil in the premix for lubrication. As it is running out of gas it is also running out of oil and can cause an engine seizure.

Being you found the fuel line shot you might as well keep going.
Don't stop at the fuel line, do the whole fuel system, you will likely find hose crap in the fuel pump, carb and primer bulb also with ethanol and the damage it does you will likely also find a lot of gumming. Carefully inspect the carb as the ports will have gumming in them too.