I found a service manual for the saw.
Air gap between ignition module and fanwheel: 0.15 – 0.3 mm
I need to get a new set of feeler gauges but will do so and make sure it is correct.
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Air gap between ignition module and fanwheel: 0.15 – 0.3 mm
I need to get a new set of feeler gauges but will do so and make sure it is correct.
salecker
Minister of Fire
There is a small chance that it could be the coil
I would look the recoil over to make sure it is all correct.
If it has the wrong size rope on it,the rope can bind on itself as it jambs in the pulley from being to small
I would look the recoil over to make sure it is all correct.
If it has the wrong size rope on it,the rope can bind on itself as it jambs in the pulley from being to small
I checked the ignition module gap; it was 0.25 mm. I checked the plug gap and checked the spark. It was orangish in colour; was wondering if a weak spark might cause this issue. With the plug out, I put the switch on choke and pulled the recoil rapidly multiple times. I didn't see any fuel running out when I titled the saw up. Yes, it would have been flooded but not hydro-locked.
I think salecker is probably correct about the recoil locking up on pull even though the recoil looks fine and pulls fine; under a load the spool might be cocking sideways and causing the issue. When I got the saw back from NY with the different recoil it worked great; however, it got worst with time. I don't use the saw on a daily basis. Back in October of 2021 I used the saw for several days and started it multiple times cutting some big oak. Never had an issue. The saw sat for a few months and now it seems that it is acting up on almost every time I go to start the saw.
I think salecker is probably correct about the recoil locking up on pull even though the recoil looks fine and pulls fine; under a load the spool might be cocking sideways and causing the issue. When I got the saw back from NY with the different recoil it worked great; however, it got worst with time. I don't use the saw on a daily basis. Back in October of 2021 I used the saw for several days and started it multiple times cutting some big oak. Never had an issue. The saw sat for a few months and now it seems that it is acting up on almost every time I go to start the saw.
Isaac Carlson
Minister of Fire
I am going to ask what your background is and how much saw experience you have. Some people just don't have what it takes to start a mid sized chainsaw. A friend of mine has trouble starting his 390 and I need to get him set up with a smaller saw because he describes it a lot like you do. 'Sometimes it's easy and sometimes it just won't go". I can start the saw fine every time, but I also know how to start a big saw, so it's easy for me.
First off, how old are you? The friend I mention is going on 70. He is pretty fit, but his age is starting to show. Some days he just doesn't have it at all in the strength dept., other days he will outwork me, often lifting 100+ lb chunks.
Does the chain spin at idle?
Can you spin the chain easily by hand?
Do you atart it with the chain brake on or off?
What style of starting do you use?
Does the ripe retract smoothly and evenly every time, even when it is hard to start?
What is your oil mix ratio? 50:1? If so, what brand oil and how are you measuring?
How much rope can you pull out of the recoil and what diameter is it?
First off, how old are you? The friend I mention is going on 70. He is pretty fit, but his age is starting to show. Some days he just doesn't have it at all in the strength dept., other days he will outwork me, often lifting 100+ lb chunks.
Does the chain spin at idle?
Can you spin the chain easily by hand?
Do you atart it with the chain brake on or off?
What style of starting do you use?
Does the ripe retract smoothly and evenly every time, even when it is hard to start?
What is your oil mix ratio? 50:1? If so, what brand oil and how are you measuring?
How much rope can you pull out of the recoil and what diameter is it?
I am going to ask what your background is and how much saw experience you have.
I have been using this saw for about five to six years. I have started this saw more times than I can count. The saw was a gift; not sure how many hours is on the saw. Wood is my main heat source; haven't used any other heat since installing the wood stove. I do most of my own cutting. Back in October I used the saw several days; cutting up an oak that was over 20 inches in diameter at the base. I started the saw many times; often I will turn the saw off if it is going to be idling while I do something not cutting. The saw starts easily when I can pull the recoil so I don't worry about restarting the saw.
Does the chain spin at idle?
No, the chain doesn't spin at idle. Of course if I am going to carry the saw while it is running, I put the brake on. However, when I start the saw and take the brake off, the chain doesn't move until I hit the throttle.
Can you spin the chain easily by hand?
Yes, I always check the chain tension when I start to cut and adjust it; not loose but not so tight that I can't spin the chain by hand. I do the pull test to see how much slack is in the chain and the spin test to make sure the chain can move by hand.
Do you atart it with the chain brake on or off?
I start it with the chain brake on. However, I think the issue is there even with the chain brake off; I could test this.
What style of starting do you use?
I always start the saw on the ground. I engage the brake. I put the choke on full. I put my foot on the handle, my left hand on the top handle. I pull the rope until I feel the recoil pawls engage the flywheel, I then pull rapidly on the recoil. I repeat pulling until the saw does the "burp." I then move the choke level to the next level and repeat above until it starts.
Does the ripe retract smoothly and evenly every time, even when it is hard to start?
Yes.
What is your oil mix ratio? 50:1? If so, what brand oil and how are you measuring?
I am currently using the Walmart Tech brand 2-cyble oil; the same oil I have been using awhile now since I got a gallon. When I first got the saw I used those little pre-measured bottles but they are more expensive. I have a glass measuring cup that is graduated in ounces so I can do a precise metering of the oil. I mix to 50:1 or slightly more oil at times but never less and never over oil to the point it causes issues; maybe just a tad more (someone said that adding just a tad more oil to the mix can improve the life of the saw.) Just to be sure, I always check the ratio chart when mixing fuel again so that I don't mix wrong.
How much rope can you pull out of the recoil and what diameter is it?
When it won't pull; and this is like a dead lock-up of the saw, after engaging the pawls in the flywheel It will only pull a short distance; to me it is at the point when the piston goes under compression. When I can't pull rapidly to start the saw, I can pull slowly on the recoil and it will move the crankshaft. One time when I couldn't start the saw, I pulled on the recoil several times and it seemed to ease up and I could start the saw and I used it to cut up some tulip poplar.
I actually sent the saw to NY to a mechanic there. This was a few years ago when the saw first started acting up. He couldn't get the saw to repeat the issue but installed a different recoil. When I got the saw back, it appeared to be fine. I used it and all seemed good but then last year the issue flared up at times and now it seems to be almost all the time. Oh, he also ported the muffler for me while he had the saw.
I have been using this saw for about five to six years. I have started this saw more times than I can count. The saw was a gift; not sure how many hours is on the saw. Wood is my main heat source; haven't used any other heat since installing the wood stove. I do most of my own cutting. Back in October I used the saw several days; cutting up an oak that was over 20 inches in diameter at the base. I started the saw many times; often I will turn the saw off if it is going to be idling while I do something not cutting. The saw starts easily when I can pull the recoil so I don't worry about restarting the saw.
Does the chain spin at idle?
No, the chain doesn't spin at idle. Of course if I am going to carry the saw while it is running, I put the brake on. However, when I start the saw and take the brake off, the chain doesn't move until I hit the throttle.
Can you spin the chain easily by hand?
Yes, I always check the chain tension when I start to cut and adjust it; not loose but not so tight that I can't spin the chain by hand. I do the pull test to see how much slack is in the chain and the spin test to make sure the chain can move by hand.
Do you atart it with the chain brake on or off?
I start it with the chain brake on. However, I think the issue is there even with the chain brake off; I could test this.
What style of starting do you use?
I always start the saw on the ground. I engage the brake. I put the choke on full. I put my foot on the handle, my left hand on the top handle. I pull the rope until I feel the recoil pawls engage the flywheel, I then pull rapidly on the recoil. I repeat pulling until the saw does the "burp." I then move the choke level to the next level and repeat above until it starts.
Does the ripe retract smoothly and evenly every time, even when it is hard to start?
Yes.
What is your oil mix ratio? 50:1? If so, what brand oil and how are you measuring?
I am currently using the Walmart Tech brand 2-cyble oil; the same oil I have been using awhile now since I got a gallon. When I first got the saw I used those little pre-measured bottles but they are more expensive. I have a glass measuring cup that is graduated in ounces so I can do a precise metering of the oil. I mix to 50:1 or slightly more oil at times but never less and never over oil to the point it causes issues; maybe just a tad more (someone said that adding just a tad more oil to the mix can improve the life of the saw.) Just to be sure, I always check the ratio chart when mixing fuel again so that I don't mix wrong.
How much rope can you pull out of the recoil and what diameter is it?
When it won't pull; and this is like a dead lock-up of the saw, after engaging the pawls in the flywheel It will only pull a short distance; to me it is at the point when the piston goes under compression. When I can't pull rapidly to start the saw, I can pull slowly on the recoil and it will move the crankshaft. One time when I couldn't start the saw, I pulled on the recoil several times and it seemed to ease up and I could start the saw and I used it to cut up some tulip poplar.
I actually sent the saw to NY to a mechanic there. This was a few years ago when the saw first started acting up. He couldn't get the saw to repeat the issue but installed a different recoil. When I got the saw back, it appeared to be fine. I used it and all seemed good but then last year the issue flared up at times and now it seems to be almost all the time. Oh, he also ported the muffler for me while he had the saw.
Isaac Carlson
Minister of Fire
Nice, very clear answers.
Is the saw hot or cold when it acts up? Is it always one or the other?
Has the saw been sitting a while when it happens? (if it does it only when cold)
Is the saw hot or cold when it acts up? Is it always one or the other?
Has the saw been sitting a while when it happens? (if it does it only when cold)
I have seen it do it hot or cold. Lately it is acting up when I go to start it for the first time so yes, lately it is when the saw is cold.
This is pretty baffling to say the least. It almost sounds like a partially seized bearing , but I would not expect one to have the life span/ longevity of what is being explained.
My only other thought is a sticky valve/reed that is causing a compression lock (hence being able to pull the saw over slowly).
I think this may have been touched on earlier and for the sake of clarity...Has the saw EVER been difficult to turn over with the spark plug removed?
My only other thought is a sticky valve/reed that is causing a compression lock (hence being able to pull the saw over slowly).
I think this may have been touched on earlier and for the sake of clarity...Has the saw EVER been difficult to turn over with the spark plug removed?
I have taken the spark plug out, and carefully by hand, just using a few fingers, turn the flywheel by hand and I can't feel any indication of possible bad bearings; it rotates smoothly. When I can, I think I will make a video of starting the saw. Seeing is easier that trying to explain. With the plug out, there is no indication of not being able to pull the starter recoil. It could be carb related; I guess it wouldn't hurt to rebuild the carb. However, I didn't really see an indication of hydro-lock and I would think hydro-lock would prevent from pulling the rope slowly although I don't know.
Yes, I have. When I had the muffler off, I examined the piston and it appeared fine; maybe a scratch or two but no scoring. I also did not see any carbon build-up on the piston.
Isaac Carlson
Minister of Fire
That video is full of bad info. Wd40 is NOT a lubricant. It is a water displacement formula.
Recoils that stick need to be taken apart, cleaned, retensioned, oiled with 1-3 drops of real 10 wt oil and put back together.
As far as the OP's saw, it sounds like what I described with my older friend. That's the only thing I can think of. The OP never did say how old she is. That makes this very difficult, even if it sounds silly. A 290 is a good sized saw for most homeowners and can be difficult to start since there is no compression release, especially when cold. I can pock up my 390 by the cord and it will hold compression for a long while when cold, and cool/cold weather only amplifies the symptoms. If I went to start it right now, it would be like pull starting a vw bug. 160 lbs os great compression. There could be carbon buildup from the cheap oil and adding extra, along with rich tuning. Most people tune 2 strokes rich. I tune right on the edge with synthetic oil and carbon is not a problem. I check my tune every time I use a saw in different weather. People often comment "what are you doing" "what's the screwdriver for" or something like that because they don't understand 2 strokes.
My guess is the saw is fine or maybe has increased compression from carbon. Those are the 2 things I come up with. We have absolutely no idea what kind of shape the op is in, and starting a saw with good compression on the ground without a compression release when you are higher in the age range is no easy task. I ONLY drop start unless feeling for compression or something else, but not everyone should do that. My older friend has tried to drop start and only succeeded in gashing his leg with the bar because he did not understand counter rotation. He is pretty fit compared to most men his age and still has trouble starting the saw some days. Most days he is fine. He calls me and says "Ike, my saw won't turn over today, can you take a look and get it going?" It always starts like normal for me.
The op said she sent it to a guy in new york who looked at it, changed the recoil, and sent it back. It worked fine for a while and issue returned. My guess is he tested it and filled the tank with synthetic mix or equivalent and the oil film in the cylinder was not as thick/viscous as it ised to be until it worked through the system. As the op added fuel and diluted the mix, the symptom returned.
My suggestion is to use synthetic oil in pre-measured containers, mixing only 1 gallon of premium non ethanol gas.
Run the saw on the current tank until empty, then refill with the new mix and run a few tanks and see if the issue returns.
This is my best guess with the information we have been given.
Recoils that stick need to be taken apart, cleaned, retensioned, oiled with 1-3 drops of real 10 wt oil and put back together.
As far as the OP's saw, it sounds like what I described with my older friend. That's the only thing I can think of. The OP never did say how old she is. That makes this very difficult, even if it sounds silly. A 290 is a good sized saw for most homeowners and can be difficult to start since there is no compression release, especially when cold. I can pock up my 390 by the cord and it will hold compression for a long while when cold, and cool/cold weather only amplifies the symptoms. If I went to start it right now, it would be like pull starting a vw bug. 160 lbs os great compression. There could be carbon buildup from the cheap oil and adding extra, along with rich tuning. Most people tune 2 strokes rich. I tune right on the edge with synthetic oil and carbon is not a problem. I check my tune every time I use a saw in different weather. People often comment "what are you doing" "what's the screwdriver for" or something like that because they don't understand 2 strokes.
My guess is the saw is fine or maybe has increased compression from carbon. Those are the 2 things I come up with. We have absolutely no idea what kind of shape the op is in, and starting a saw with good compression on the ground without a compression release when you are higher in the age range is no easy task. I ONLY drop start unless feeling for compression or something else, but not everyone should do that. My older friend has tried to drop start and only succeeded in gashing his leg with the bar because he did not understand counter rotation. He is pretty fit compared to most men his age and still has trouble starting the saw some days. Most days he is fine. He calls me and says "Ike, my saw won't turn over today, can you take a look and get it going?" It always starts like normal for me.
The op said she sent it to a guy in new york who looked at it, changed the recoil, and sent it back. It worked fine for a while and issue returned. My guess is he tested it and filled the tank with synthetic mix or equivalent and the oil film in the cylinder was not as thick/viscous as it ised to be until it worked through the system. As the op added fuel and diluted the mix, the symptom returned.
My suggestion is to use synthetic oil in pre-measured containers, mixing only 1 gallon of premium non ethanol gas.
Run the saw on the current tank until empty, then refill with the new mix and run a few tanks and see if the issue returns.
This is my best guess with the information we have been given.
I am not that old; although I am not going to give my age. I need to make a video. When this problems happens, I am l literally jerking the saw up off the ground. Unless I have become a 10 lb weakling in just a few months why did I have no issues starting the saw last October? No, there is something going on with this saw. OK, I won't use anything like WD 40 but I will carefully removed the spool and examine the recoil spring. I also have an inspection camera so I will see about putting together some videos to show the piston. I will insert the camera through the muffler and through the spark plug hole. I make a video of me attempting to start the saw when it acts up. I have a YouTube channel where I can upload the videos as I am guessing I can't do direct video uploads on the forum. It may be a few days before I can get the videos done.
I want to say that I am very grateful for all the help everyone is giving me.
When it does this I would remove spark plug wire. Touch nothing else and pull it over many times to see if it tends to lock up, or if it feels like normal compression every time. By the process of elimination, you take the spark at the wrong time out of the equation. If it pulls over consistently the same, timing or coil. You then know the spark is causing it.
A bad coil can show symptoms in many ways. I had my 2 cylinder Koehler tractor die over the summer. No warning, like it was shut down. Troubleshoot no spark. Checked wiring, looked at diagrams, ate lunch. Went to try things with a test light, started. Got hot, died. Coil time. After changing it, I noticed I no longer need to prime the fuel in carb after sitting a few days. Thought it was odd that it seemed to always have a dry fuel bowl, chalked it up to no check valve or fuel pump allowing carb to drain back into tank. Started that way for years since I got it. It always cranked a bit when cold starting too. After changing the coil, I started it a month later, and it fired right up. No more prime needed down carb. Starts cold on the fist turn. Coil must have been weak and I was masking the problem forever.
A bad coil can show symptoms in many ways. I had my 2 cylinder Koehler tractor die over the summer. No warning, like it was shut down. Troubleshoot no spark. Checked wiring, looked at diagrams, ate lunch. Went to try things with a test light, started. Got hot, died. Coil time. After changing it, I noticed I no longer need to prime the fuel in carb after sitting a few days. Thought it was odd that it seemed to always have a dry fuel bowl, chalked it up to no check valve or fuel pump allowing carb to drain back into tank. Started that way for years since I got it. It always cranked a bit when cold starting too. After changing the coil, I started it a month later, and it fired right up. No more prime needed down carb. Starts cold on the fist turn. Coil must have been weak and I was masking the problem forever.
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Isaac Carlson
Minister of Fire
Good idea, even though early spark tends to mercilessly rip the cord out of one's hand. I have ended up with very sore fingers a few times when being lazy about pulling, and I have a very good grip.
A very long thread about a Hard to pull ms 250. Sounds like it's a known problem on some ms 250 saws. Go to the last post on page 6 to see how setting up the pull cord may help a little.
Yeah, I think the process of elimination is needed here.
No one mentioned octane of fuel being used. Not sure if it was mentioned that a different batch of fuel has been tried. When it was sent to NY and came back without the problem, maybe the problem resurfaced when the fuel causing the issue was put in?
Gas stations can run out of a grade of fuel and can substitute a higher octane that you thought was regular. Regular octane lights and burns easier than higher octane that is more difficult to light, but higher octane burns with a smoother flame propagation when it does.
I know at first the saw was emptied, and dried out, but opening 2 stroke motors you find lots of oil from it condensing like it should, and I’m sure there is some vapors and volatility in the case being brought up to the cylinder top pulling it over.
No one mentioned octane of fuel being used. Not sure if it was mentioned that a different batch of fuel has been tried. When it was sent to NY and came back without the problem, maybe the problem resurfaced when the fuel causing the issue was put in?
Gas stations can run out of a grade of fuel and can substitute a higher octane that you thought was regular. Regular octane lights and burns easier than higher octane that is more difficult to light, but higher octane burns with a smoother flame propagation when it does.
I know at first the saw was emptied, and dried out, but opening 2 stroke motors you find lots of oil from it condensing like it should, and I’m sure there is some vapors and volatility in the case being brought up to the cylinder top pulling it over.
I don't think octane has anything to do with it, if anything higher octane would help the recoil kickback issue.
I have 3 different 2-stroke engines that I burn avgas in, including my saw, which is significantly higher in octane rating than any on road pump fuel. You would never know the difference between them when pulling the starter, once started absolutely you'd know the difference by the smell though.
I have 3 different 2-stroke engines that I burn avgas in, including my saw, which is significantly higher in octane rating than any on road pump fuel. You would never know the difference between them when pulling the starter, once started absolutely you'd know the difference by the smell though.
Thanks for that!
My MS250 is similar, sometimes MUCH harder to pull than others when it hits compression right.
My wife found this out the hard way, trying to start it while holding it upright instead of on the ground, ended up with a trip to the ER for stitches in her leg. The brand new chain was VERY sharp.
Point being, I wonder if anything is actually wrong here.... Since it's similar on some MS250s, etc. Ideal? No. But maybe that's just how it is?
EbS-P
Minister of Fire
So a different recoil made a difference for a while then the problem returned slowly. This is important. I don’t think it’s gas or oil or how strong you are or age. I’m guessing it’s something on the recoil side of the saw. It’s almost like the recoil is binding when torqued. Something may be worn causing it to miss align?
Is there any play once the recoil is installed?
Sean McGillicuddy
Minister of Fire
salecker
Minister of Fire
Do you know anyone with the same saw or one in the same family 029,039ect?
If so see if you can borrow it and when yours is hard to pull over try the recoil from a saw that isn't acting up.
If so see if you can borrow it and when yours is hard to pull over try the recoil from a saw that isn't acting up.
