Small engine questions: Chain Saw type!

[MaximPhil]

Its nice to hear its not a total loss. Like I said earlier, if you can buy non-ethanol gas at your local station then use that. Dont think you have to buy the premix gas from now on. The older saws are definitely less forgiving to ethanol. Just as important as the gas it the oil you use. If you buy quality oil made for chainsaws then it has fuel stabilizer in it and additives for the ethanol. Dont let your gas go stale either that can be just as bad.

Heres an interesting read on ethanol and chainsaws...

http://www.google.com/url?sa=t&sourc...lIn3_WDtTur-DQ

Hi WMarshy,
Thanks for that article. Tells the details of what I suspected all along.
Phil

[crazy steve]

...Just as important as the gas is the oil you use.

That can be the deal-breaker on some saws. I know I had a McCullough saw that would not run more than once with non-McCullough oil in the mix. Wrong oil, you could put a fresh tune in it, it would start/run the first time, couldn't get it started after that unless you replaced the plug. The Stihl I had didn't care....

[TopCatGr58]

Spoke Too Soon!

Well,

Looks like I spoke too soon! Went out and bought some 93 octane E10 fresh fuel, mixed up a new batch of 40:1 premix. Even with the previous $$$ TruFuel in there, was VERY HARD to get started, it would run for while but then conk out. Ran that tankful almost dry, put in the NEW E10 premix, again VERY HARD to get started, ran for a while, sound like it would bog and die!

Pulled and cleaned the plug. Checked the Comp. Level, got up to 90 psi after some 7-10 pulls...someone said that that should be okay, but not sure, not sure if 2 strokers can develop the same compression readings as a 4 stroke?? Looked into the cylinder, thought I could see some vertical "lines" along the exhaust port but wasn't sure?

I gave up for the day. Interesting Read/Article, thanks Marshy. This little saw is acting like it may be done. I can use the new chain on another machine, that was one of the more $$ expenditures, vs. the plug, primer bulb, and the $11.00 carb kit....could have gotten a whole new carb for ~$20.

If this saw will ONLY run on the $$ Trufuel, then it's not economically feasible to keep feeding it that ~$7.00 a QUART stuff vs. investing in a new machine!

Oh well, live and learn as they say.

T.C.

[ViperRon]

Sorry for the problem TC but all the facts in Marshy's reply point to the fact it may be a goner. I have had several little poulan chainsaws and had my share of problems. Like stated proper mix and good fuel is important. They have to have good filters good hoses etc to run well.

I really had very little problem with mine when I was the only one using it. First I generally go to the same place to get fuel and use the premeasured oil from poulan and mix in a container that has an exact measurement for 2 1/2 gallons mixing a gallon you have to be precise no guessing.

I had one poulan 2600 that started failing after I went to help with some tree work with my brother. Mistake one is I let him go get gas and to started off having problems. Then also had to get oil and could not find the little poulan mix bottles so opted for the new (crap ) oil and then could not get it to run consistant.

I took the saw home, took carb cleaner sprayed out all hoses, rinsed with fresh gas blew out with air dumped the gas into a sludge can. Put fresh gas and a mix of poulan oil in started and ran fine.

A weed eater I had that ran fine the first year and was drained. Next year would not start so when I rebuilt the carb the little flapper valves had distorted to were it would not pump gas the parts guy said it was the methanol gas that eat the material up. Suggested spraying some WD40 threw to keep the valves from drying out. It's been running fine the last 5 years.

The other chain saw I lent to a former friend to limb up a tree at his house. Since friend had little experience asked his neighbor a Tree Surgeon (short for mental capability of monkey who hangs in one) help him. First off they flooded it because they did not hold the handle which diss-enguages the saftey electrical so deciding I had made a bad mix the tree surgeon put his 40 to one mix in my 32 to one saw and adjusted it to run. They cut the entire tree down and cut up the wood and my friend brought me back the saw and said it was running a little weak sure enough they had adjusted it to run lean run it hard and burnt the rings out of it.

Never lend anything to anyone you would not trust on a year long trip visiting bars in mexico with your credit card and oversexed daughter and if you do it's less pain to drink the methanol.

[WMarshy]

Well,

Looks like I spoke too soon! Went out and bought some 93 octane E10 fresh fuel, mixed up a new batch of 40:1 premix. Even with the previous $$$ TruFuel in there, was VERY HARD to get started, it would run for while but then conk out. Ran that tankful almost dry, put in the NEW E10 premix, again VERY HARD to get started, ran for a while, sound like it would bog and die!

Pulled and cleaned the plug. Checked the Comp. Level, got up to 90 psi after some 7-10 pulls...someone said that that should be okay, but not sure, not sure if 2 strokers can develop the same compression readings as a 4 stroke?? Looked into the cylinder, thought I could see some vertical "lines" along the exhaust port but wasn't sure?

I gave up for the day. Interesting Read/Article, thanks Marshy. This little saw is acting like it may be done. I can use the new chain on another machine, that was one of the more $$ expenditures, vs. the plug, primer bulb, and the $11.00 carb kit....could have gotten a whole new carb for ~$20.

If this saw will ONLY run on the $$ Trufuel, then it's not economically feasible to keep feeding it that ~$7.00 a QUART stuff vs. investing in a new machine!

Oh well, live and learn as they say.

T.C.

T.C., 90 psi is getting on the low side,like I said its probably enough to make it run but its going to start hard and have poor performance. If I got those number in my snowmobile or chainsaw I would start looking at a rebuild. The cylinder is likely OK with just a light hone and would only require a piston and rings. Two strokers usually consider 110 to 130 acceptable and up to 140-150 on some liquid cooled high hp machines. The scoring you see is likely thermal breakdown of the oil. Take a look at this link, it shows what failures are for 2 strokes.

http://www.theultralightplace.com/pistons.htm

[TopCatGr58]

Hey there Marshy,

Thanks for the link, I haven't taken the saw down to piston yet, but did find an exploded view that looks fairly simple, 4 big bolts on the bottom of the saw that holds the crank and lower bearing assembly to the cylinder and top bearing assembly half! I just don't know the TORQUE value for it??

I found the RING for it...surprised it only uses 1 ring, but that's a 2-stroke I guess! Ebay, $2.25 with $1.90 S&H! The cylinder wall from what I could see didn't seem badly scored. I have some honing stones, so I'll "PLAY" with it and see if a new ring can bring it back to life? If not, then I'll stop putting any more $$ into it and junk it! Once I take the jug off, I'll look closer to the actual piston for signs of loss of lubrication wear and such, and hopefully it'll just be the worn ring.

T.C.

[WMarshy]

They come apart really easily and are just as easy to assemble too. You might want to see if you can get a piston for it also. Its typical to replace both at the same time.

If you take it apart and see scoring just on the exhaust side of the engine then it means your oil is breaking down from the heat. If its on both intake and exhaust then it means poor oil quality and possibly not enough in the mixture. If your running 32 or 40:1 then thats plenty of oil, my saw runs 50:1...

[WMarshy]

Here are a few pictures of a saw that I have apart waiting on a top end. As you can see, only the exhaust side has scuffing. I'm not entirely sure about its past but I know it was probably used and abused. If any of the scuffing you saw resembles this then its a sure bet your top end it burnt toast. Take note of the ring mark scored into the top of the bore at TDC.






Here's the intake side of the piston... looks like it has some miles but not too bad for what it is...

[motoman]

They come apart really easily and are just as easy to assemble too. You might want to see if you can get a piston for it also. Its typical to replace both at the same time.

If you take it apart and see scoring just on the exhaust side of the engine then it means your oil is breaking down from the heat. If its on both intake and exhaust then it means poor oil quality and possibly not enough in the mixture. If your running 32 or 40:1 then thats plenty of oil, my saw runs 50:1...

Better luck running if mixed the reccomened 50:1 40to 1 exagerated would be like pouring syrup thu the jets. As an ole two-stroke moto-crosser, flow volume DOES make a difference with the mix ratio. Either way, bettin' the coil is weak, heading south. BTDT with my Sachs/Dolomar saw. BTW, if that cylinder is ni-casel or chrome, wipe it out with a rag. Under no circumstances do you ever hone a nicasle cyl.!

[TopCatGr58]

Hey Motoman,

How the Heck do I tell if it's Ni-casel/chrome cylinder? I've gotten the RING, but haven't torn into the engine YET.

I was curious about the funny stepped looking ends to the ring, but after seeing the image showing the ring on the piston with an alignment pin(Thanks Marshy), I now understand that it keeps the ring from spinning, keeping it oriented in 1 position around the piston and in the bore, and that there is a right side and upside down orientation!

T.C.

[motoman]

Hey Motoman,

How the Heck do I tell if it's Ni-casel/chrome cylinder? I've gotten the RING, but haven't torn into the engine YET.

I was curious about the funny stepped looking ends to the ring, but after seeing the image showing the ring on the piston with an alignment pin(Thanks Marshy), I now understand that it keeps the ring from spinning, keeping it oriented in 1 position around the piston and in the bore, and that there is a right side and upside down orientation!

T.C.

Doubtful that it is ni-casel with Poulans as unfortunatly they were a 'use till it dies' throwaway motor. If it were, cyl. would look likea mirror. Just out of curiosity, check for play up and down of the rod needle bearing at the crank. If too much play, port timing will be off and it will be difficult to start and hardly run if it does start. They're a two piece crank that has to be seperated to change out the rod/crank needle bearing, and aligned and correctly balanced put back together( that would kill any idea of re-building or even a new ring). BTW, one ring IS the norn for 125cc and under. 250cc and larger use two compression rings. I'd put a new ring on that existing piston, use a universal 'dingle-ball' hone on the cyl. just to show a cross-hatch pattern, don't waste time measuring thihgs as two strokes are pretty forgiving and throw it back together(have put new piston and ring in my son's 125cc at races between heats to give it some 'kick' for the last heat). If it runs, fine, if not......junk it.