My 38cc Craftsman wont stay running.

[whitezin65]

I Have a 1.5 year old, 16", 38cc Craftsman chainsaw w/no more than 25 hours on it.  It ran like a champ for several months this fall, but now it wont run for more than a few minutes.  My trouble seemed to start after I mixed up a new batch of fuel.  It wouldn't start @ all.  I replaced the fuel filter & spark plug, & cleaned the air filter & spark arrestor screen (which wasn't really dirty). I adjusted the idle speed up a bit, & now it runs & cuts for a few minutes, but then stops & is very difficult to get started again.  After doing some reading/research, I thought that my fuel mixture (40:1) might be a little lean, so I drained the tank & added another 1/8th ounce or so of 2 cycle engine oil to my gallon of fuel, but that didn't seem to help either.  The spark plug the Sears parts folks gave me is longer than the old one.  Could that be my problem?
Can anyone help me out?

[ladylake]

 Check the spark arrestor screen in the muffler for being clogged first, then report back..    Steve

[whitezin65]

Check the spark arrestor screen in the muffler for being clogged first, then report back..    Steve

No offense, but if you had bothered to read my entire post you'ld see that I stated that I did clean the spark plug arrestor screen even though it wasn't dirty.

[thecfarm]

whitezin65,welcome to the forum.You say it runs for a few minutes. during that few minutes does it run just fine? When it stops running does it fade out of just dies,rev up?

[whitezin65]

 :-[

whitezin65,welcome to the forum.You say it runs for a few minutes. during that few minutes does it run just fine? When it stops running does it fade out of just dies,rev up?

No, it runs pretty rough & tries to die frequently unless I keep it revved pretty high.  When it stops, it doesn't rev up, fade out, or get bogged down, it just dies.  Once it fires up, I can usually keep it running for a bit, but sometimes it stops right away.  I should mention that my modle only has an idle adjuster screw.  There are posts for high & low adjustments, but I can't imagine what kind of tool is needed to get in there to adjust them.

[Z50guru]

I don't believe the spark plug is an issue here. Have you drained your fuel tank to have a good look at the fuel line? The ethanol in today's pump gas is destructive to small engine components, especially rubber. Make sure the fuel line is not collapsed in on itself. If you can fish the line out of the tank enough to be able to feel the line yourself, it should be relatively firm and should rebound to its original shape when squeezed. I have found many fuel lines that will just "squish" apart like cooked pasta due to ethanol enriched pump fuel. If all is good there, adjust your low speed mixture needle counter clockwise "enrichening" until it stops. Same with the high curcuit if the saws stumbling or bogging at full throttle. This action should improve your low end symptoms a bit. You can keep your fuel mixture at 50:1. Your carburetor has caps on the high and low speed adjustment screws to prevent the consumer from being able to tune the saw towards the "rich" side. Thank the EPA for that. Your saw may require a mixture that can not be attained without the removal of these "EPA" caps. This is a common scenario with box store saws once the engine has "broken in".  If your saw does not have caps over the carb screws, you will often find that a special tool is required at this point to properly tune the carb. So here's how you defeat the EPA and avoid purchasing another saw. Locate the carb caps and remove them with needle nose pliers or a small flat head driver. Or if the caps are recessed, take a wood screw an thread it into the center of the cap until its got a good hold on the plastic, and pluck the cap out. Often the air screw at this point can be adjusted via a common small screw driver.  Reassemble, and richen the high and low speed circuits 1/4 turn counterclockwise. Repeat until the saw runs and revs properly. If the fuel screws are of the "special tool" type, you can use a dremel tool with a small cutoff wheel to grind a recessed line into the face of the fuel screw so as to allow adjustment with a small flat head driver. I believe your problem lies not in the "fuel mix" ratio. Your saw needs richened up via the mixture screws. It may need a mixture richer than the manufacturer and or EPA has endowed the consumer with the ability to attain. Heres where many people will discard the saw and buy a new one. And guys like me will buy them for dirt cheap, and have a great running saw in no time!  8)

[Z50guru]

Heres the tool you need for adjusting your carb. 

http://www.ebay.com/itm/CARBURETTOR-ADJUSTING-SCREWDRIVER-D-TYPE-TOOL-FITS-SOME-ZAMA-CHECK-LISTING-/400602422931?pt=US_Chainsaws&hash=item5d45c3de93

[whitezin65]

Z50guru: Thankyou so much sir!  I will give your recomendations a try & see where that gets me.

[Z50guru]

You are most welcome sir.  Welcome to FF and best of luck with your saw. Please report back and let us know if things worked out for ya  ;)

[Andyshine77]

Pop off the exhaust can and have a look at the piston and cylinder and report what you see.

[MidWestTree]

I'd definitely remove the muffler and have a look at the piston for scoring or any other damage causing a loss of compression before spending a dime on that saw. Basics first...

[whitezin65]

Thanks Andyshine77 & MidWestTree:  I had the muffler off when I cleaned the spark arrestor screen, & everything looked fine to me.  No grooves, scoring or pits on the sides of the piston or head.  Remember, this is an engine w/less than 30 hours on it.

[Andyshine77]

Is the fuel itself fresh? Your issues after adding new fuel mix sounds like the mix was bad. Because you lack experience, the basic information you gave is a bit vague, so it could be any number of things. Check the fuel lines for cracks, make sure the tank vent is working, check compression, as you cant always see everything from the exhaust port. The list goes on, pretty simple stuff really.

The moral of the story. You have a 100 dollar saw with no dealer support. The saws hours mean nothing, a few minutes running on fuel with no oil, will do plenty of damage. Same could be said about running a dull chain and over heating the poor thing.     

[Oliver1655]

When you made a fresh mix of fuel did you do it with the same batch of gas you did the first one or did you go to the filling station for fresh gas?  I also stay away from ethanol gas.  I use 91 octane ethanol free (marine grade) with a 40:1 ratio.

Fresh fuel, check fuel lines, screw you jets all the way in then back them out 1 full turn, new spark plug (check gap), & give it another try.
Wish you the best.

[AdkStihl]

this is an engine w/less than 30 hours on it.

Not to offend you, but that's almost double or more the life expectancy on those box store saws.

[beenthere]

After doing some reading/research, I thought that my fuel mixture (40:1) might be a little lean, so I drained the tank & added another 1/8th ounce or so of 2 cycle engine oil to my gallon of fuel,

Seems this is the best clue to lead up to your trouble.
Maybe old fuel in the tank to start with, added questionable new fuel and had trouble, adjusted idle speed, then dumped old fuel out and added oil to the mix..  A combination of things built up here that add up for your frustration.

[MidWestTree]

Thanks Andyshine77 & MidWestTree:  I had the muffler off when I cleaned the spark arrestor screen, & everything looked fine to me.  No grooves, scoring or pits on the sides of the piston or head.  Remember, this is an engine w/less than 30 hours on it.

That's good news, and other posters have given good advice on revisiting base carb settings and tuning from there. You may well have gotten some bad gas at some point, but with good compression and ignition ruled out shouldn't take much to get it back up and running.

[whitezin65]

this is an engine w/less than 30 hours on it.

Not to offend you, but that's almost double or more the life expectancy on those box store saws.

Well, that's discapointing to hear!  Not to offend you, but I sure hope you're wrong .
My fuel lines look fine.  Nice & rubbery/springy. Not mushy.  My gas was fresh as of a couple weeks ago when I mixed a new batch of fuel and started having trouble.  87%  Not sure if it contains ethanol.  I'll have to check the next time I'm @ that service station.  I ground some grooves in the high and low posts & am currently attempting to adjust them 1/4 turn counter clockwise each time I try to start it.

[CTYank]

No mention yet of who made the plug. I've a 42cc Poulan, came with a Torch plug. Real PITA on hot restarts especially. Tossed the Torch for an NGK- that problem is history. (Torch plugs also have a history of dropping ground electrodes, thus pounding pistons.)

Your saw is mostlikely a Poulan. If it has a Torch plug, I'd suggest same. Some experts suggest early on when you have engine probs: put in a known-good plug.

Almost certainly, the engine will benefit greatly from proper carb adjustment. My PP4218 sure did.

[Ward Barnes]

I don't know Craftsman's agreement with their manufacturer, however, many box stores have a blanket return policy where they will replace/refund any defective chainsaw without cost to the original purchaser or cost to the store itself.  Might be worth checking into.

God Bless, Ward and Mary.

[Al_Smith]

Oh they will run more than 30 hours but probabley 30 hours is all they get ran .They buy the things to cut a little firewood or trim the apple tree and the first time they quit running that does it .

So off the the repair shop which most won't even work on them or get the bad news the price for repairs cost about double the saw is worth .

The dealer makes a fantastic deal ,leave the saw they take 10 bucks off ,don't charge for analizing the saw .Sell them an MS 250 or  290 and out the door they  go .The saw ends up in the dead pile .--more

[Al_Smith]

Don't blame Poulan .They build the saws on spec for Sears and Roebuck .

In the last year ,year and a half I've had 4 or 5 cross my door .Some in a cute little carrying cases .Some with a 3/8" LP chain some with a .325 chisel believe it or not .What they all had in common was deteriated fuel lines .Some broken off inside the tank .Fill them up they run until the fuel gets below the broken off line .The plastic lines they use get hard as a rock .You just about have to cut them off the carb fitting .

[AdkStihl]

About a month ago I had an old Craftsman and a Jonsered 2036 on the bench. They were IDENTICAL except the clothes they were wearing.
The Crapsman just needed a fuel system overhaul. The Jonny had an airleak that wasn't worth me chasing.

[Al_Smith]

Usually it's about a foot of plastic line and a half hour .More times than not it's somebody I know and the price is a case of Budweiser.

I found the one guy a Stihl 015 for next to nothing and he's tickled pink .Has a case too ,woo woo . :D

[AdkStihl]

Usually it's about a foot of plastic line and a half hour .More times than not it's somebody I know and the price is a case of Budweiser.

I found the one guy a Stihl 015 for next to nothing and he's tickled pink .Has a case too ,woo woo . :D

.......same here. Except its BudLight

[The Ripper]

this is an engine w/less than 30 hours on it.

Not to offend you, but that's almost double or more the life expectancy on those box store saws.

Well, that's discapointing to hear!  Not to offend you, but I sure hope you're wrong .
My fuel lines look fine.  Nice & rubbery/springy. Not mushy.  My gas was fresh as of a couple weeks ago when I mixed a new batch of fuel and started having trouble.  87%  Not sure if it contains ethanol.  I'll have to check the next time I'm @ that service station.  I ground some grooves in the high and low posts & am currently attempting to adjust them 1/4 turn counter clockwise each time I try to start it.

Take the original plug to Lowes or where ever they stock E3 plugs and cross it over. I run these" Wonder Plugs" in all my power equipment with no ill effects  or gains    Sounds like the carb might have some trash, etc, just a suggestion.

[Al_Smith]

Well if it has compression it has to be fuel or spark .That's all there is .

[Z50guru]

this is an engine w/less than 30 hours on it.

Not to offend you, but that's almost double or more the life expectancy on those box store saws.

Well, that's discapointing to hear!  Not to offend you, but I sure hope you're wrong .
My fuel lines look fine.  Nice & rubbery/springy. Not mushy.  My gas was fresh as of a couple weeks ago when I mixed a new batch of fuel and started having trouble.  87%  Not sure if it contains ethanol.  I'll have to check the next time I'm @ that service station.  I ground some grooves in the high and low posts & am currently attempting to adjust them 1/4 turn counter clockwise each time I try to start it.

I'll add as well that if while adjusting your fuel screws you get the feeling they are way out of whack, you can baseline the carb again by turning both screws in until lightly seated and then back them both out 1 1/2 turns.  This will get you back in the ball park where most saws will at least run and finer tuning from there can be done.

[AdkStihl]

Take the original plug to Lowes or where ever they stock E3 plugs and cross it over.

No....never.
NGK BPMR7A

[The Ripper]

Take the original plug to Lowes or where ever they stock E3 plugs and cross it over.

No....never.
NGK BPMR7A

??? I know there's a lot mixed reviews on this particular  brand of plug but to be honest with you ,I've been using E3's in all my 2-cycles and commercial mowing equipment for two years without a mishap of misfiring or fouling . With the E3's you just have make sure the ground electrode is completely centered. I think their biggest issue is limited heat ranges,where others have  vast heat ranges to counter any plug related issues. 

[AdkStihl]

I've been using E3's in all my 2-cycles and commercial mowing equipment for two years without a mishap of misfiring or fouling .

I've never had an issue with NGK plugs either.