Jonsered 49sp bog

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fullchoke

fullchoke

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I responded to a craigslist ad for a different chainsaw and the seller had this jonsered 49sp that he said he would also sell, because he said he was done trying to fix it. He said it quit in the cut, and now would only idle. That he had been through the carb many times without finding anything wrong. So now I have it. I also pulled the carb and everything looks clean, and the muffler was cleaned too, by the prior owner in his attempts to fix it. I checked for spark and it is good. I started the saw and it idles reasonably well, but it won't take any throttle, none whatsoever. It will bog. It will still idle even under full throttle for a short time, with a severe bog, but with no increase in revs. With the top and the air filter off, the back of the carb gets wet with gas. After you let off the trigger it goes back to a normal idle, without the bogging sound. Is this maybe something wrong with the ignition? On the mike acres site it says this saw has no points, but others talk about this saw having points. The chain and clutch drum move very freely, there is no chain brake, but it kinda acts like there is one and it's on. The guy I got this saw from, is probably a better mechanic than I am. I would appreciate any ideas from the experts here.
Thanks
 
Cantdog
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Several things to check,
First make sure it has the correct carb to isolation block gasket....the ones that come in carb kits will NOT work. They are not big enough around the outside edge to properly seal the impulse corridor. You can make one or if you have a Husky dealer handy one from a 61, 266, 268, 272 will work fine.
Second, while you are at the carb pull the top cover off and right beside where the fuel inlet is there is a 1/4" diameter hole with a very fine screen at the bottom of the hole. This is your final fuel filter and will clog up with crap. Personally I would also buy a OEM Tilotson carb kit and rebuild the carb from scratch and also be certain your fuel line is tight on the hose barb on the carb and has no cracks or pin holes.
Third, make certain that all the cyl bolts are tight and it hasn't blown a cyl base gasket.
Last you need to pull the flywheel and carefully inspect the points for burning, pitting or a very close gap. The contacts should match evenly together and be gapped at 0.016" Make certain you have a good sparkplug and the boot connection is in good order.
 
fullchoke

fullchoke

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Thanks Cantdog for the ideas, I was looking at the carb, manifold, and gasket and noticed that the impulse hole is not covered by the gasket. I came here and then saw your post. Thank you very much! I will look to buy another gasket for one of those Husky saws. Then go down your list if it still has a problem. The funny thing is the guy said the saw quit in the cut. I would not think it would ever run with that impulse hole open, but it does idle. I wonder if something else made it quit in use, and while he fixed that with a cleaning and the carb kit it still didn't work because of the gasket. It looks like a nice saw, good compression with a new bar and chain. I will report back how it runs with the new gasket when I find one.
I also noticed you have many 49sp parts saws in your nice list of saws. Do you have knob that holds the air cleaner lid on, I could buy? Mine just has a big wing nut holding it on, I don't know what it actually should look like.

Thanks,
Greg
 
Woodslasher

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Not sure I understand this statement.
Have you ever tried to rev a saw with the brake engaged, accidentally or otherwise? I have occasionally when the brake "trips" itself and the saw will try to rev but the bar and chain won't spin and the engine acts like it's under a huge load. What he's saying is it feels like that, but the clutch drum spins freely when the saw isn't running so there obviously isn't a chain brake or something else keeping the clutch drum and, consequently the chain, from turning
 
sundance

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Have you ever tried to rev a saw with the brake engaged, accidentally or otherwise? I have occasionally when the brake "trips" itself and the saw will try to rev but the bar and chain won't spin and the engine acts like it's under a huge load. What he's saying is it feels like that, but the clutch drum spins freely when the saw isn't running so there obviously isn't a chain brake or something else keeping the clutch drum and, consequently the chain, from turning
Got it......thanks.
 
Cantdog
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I responded to a craigslist ad for a different chainsaw and the seller had this jonsered 49sp that he said he would also sell, because he said he was done trying to fix it. He said it quit in the cut, and now would only idle. That he had been through the carb many times without finding anything wrong. So now I have it. I also pulled the carb and everything looks clean, and the muffler was cleaned too, by the prior owner in his attempts to fix it. I checked for spark and it is good. I started the saw and it idles reasonably well, but it won't take any throttle, none whatsoever. It will bog. It will still idle even under full throttle for a short time, with a severe bog, but with no increase in revs. With the top and the air filter off, the back of the carb gets wet with gas. After you let off the trigger it goes back to a normal idle, without the bogging sound. Is this maybe something wrong with the ignition? On the mike acres site it says this saw has no points, but others talk about this saw having points. The chain and clutch drum move very freely, there is no chain brake, but it kinda acts like there is one and it's on. The guy I got this saw from, is probably a better mechanic than I am. I would appreciate any ideas from the experts here.
Thanks
Yes this saw has a points ign. Some of Acres info is not always spot on though it is a handy source of info. Something else I should have mentioned earlier is while you have the carb off, pull the "H&L" needles and using a can of wd40 or similar with the red straw applicator inserted tightly in each jet give a squirt while looking down the carb bore with the throttle flap held open.......there should be spray coming out the "H" in the center of the bore and when in the "L" there should be two places where fluid should be entering....one before and one after where the throttle flap would sit at idle. This will tell you is you have a clog behind the welch plugs. Sorry the air box cover bolts are rather hard to come by and had a tendency to fail if over tightened so I only have a couple extras and with over a dozen of the 52/49 series saw in operation I kinda keep them close. Keep an eye out for a parts saw.....either a 49spp or 52/52E and/or keep watch on ebay.
 
fullchoke

fullchoke

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Thanks Woodslasher, That is exactly what I meant.

Thanks, Cantdog, So far I only checked the high side and that was fine. I figured the low side was working since it would idle but didn't think about one of the 2 holes possibly being plugged. I will look for that knob. Too bad it is hard to find, usually means a premium price. This is my 1st 49sp, but I do have a Jonsered 66e I got many years ago with a bad switch, and possible other problems.(I never tried to fix it). I found a Makita 6401 for $10 that turned out to be a very strong, nice, quite saw. The 49sp switch looks very similar as I remember it on the 66, are they interchangeable do you know? The Makita once developed a problem, and I'm not going out woodcutting again without a backup or 2.

One of the things I have questioned before the impulse leak was found was about the coil or condenser, because I had heard that some coils can run but short out when hot, then work again when cooled. I had a spark plug that did this in a pressure washer that ruined my day. I even bought a new carb before I found that one. I haven't heard about them shorting off idle, but don't know if this could happen with a coil or condenser. I had thought a bad condenser might still run, but poorly since the spark would be weak or not run at all. This engine problem didn't want to give me 1 extra rpm off idle(or so it felt) but would keep idling. Sometimes the odd problems are very difficult to find. I hope I can learn a little more about the symptoms expected when something like a coil or condenser go bad, but not totally stop working.
Thanks
 
Cantdog
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Thanks Woodslasher, That is exactly what I meant.

Thanks, Cantdog, So far I only checked the high side and that was fine. I figured the low side was working since it would idle but didn't think about one of the 2 holes possibly being plugged. I will look for that knob. Too bad it is hard to find, usually means a premium price. This is my 1st 49sp, but I do have a Jonsered 66e I got many years ago with a bad switch, and possible other problems.(I never tried to fix it). I found a Makita 6401 for $10 that turned out to be a very strong, nice, quite saw. The 49sp switch looks very similar as I remember it on the 66, are they interchangeable do you know? The Makita once developed a problem, and I'm not going out woodcutting again without a backup or 2.

One of the things I have questioned before the impulse leak was found was about the coil or condenser, because I had heard that some coils can run but short out when hot, then work again when cooled. I had a spark plug that did this in a pressure washer that ruined my day. I even bought a new carb before I found that one. I haven't heard about them shorting off idle, but don't know if this could happen with a coil or condenser. I had thought a bad condenser might still run, but poorly since the spark would be weak or not run at all. This engine problem didn't want to give me 1 extra rpm off idle(or so it felt) but would keep idling. Sometimes the odd problems are very difficult to find. I hope I can learn a little more about the symptoms expected when something like a coil or condenser go bad, but not totally stop working.
Thanks
If it's an ign problem that causing this it will be the points most likely and condenser possibly which is a PITA because it is not replaceable by itself on this model......it is made into the points plate so you have replace the whole thing. 40 year old points more likely....and I will bet they have worked/worn together causing to small a gap. But I would get the carb gasket cured and make certain the cyl base gasket is not blown.......these only about 0.007" when compressed and if the cyl bolts loosen a bit they can blow pretty easy. Yes the switch on the 49 is the same as the 66E.

Where are you located in Oregon?
 
fullchoke

fullchoke

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Thanks.
I have ordered a new gasket. I will check the base gasket. Wouldn't it not idle if that base gasket were blown. It sounds like the way this saw is built, with it's unique proprietary parts that are probably obsolete by now, I should keep it in a back up mode or sell it if the gasket gets it running, and while it's still working. If it doesn't run, it would be a parts saw. The guy I got it from said he really liked it when it was working.
Just south of Portland
 
Cantdog
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Thanks.
I have ordered a new gasket. I will check the base gasket. Wouldn't it not idle if that base gasket were blown. It sounds like the way this saw is built, with it's unique proprietary parts that are probably obsolete by now, I should keep it in a back up mode or sell it if the gasket gets it running, and while it's still working. If it doesn't run, it would be a parts saw. The guy I got it from said he really liked it when it was working.
Just south of Portland
Good that gasket may well be the entire problem.....at the very least it will eliminate a very real problem. The cyl base gasket being blown out could very well stop it from running but if it were small tear it would run like what you're talking about....again it would relate to an impulse issue, not allowing it to build enough vac to pump fuel. Generally a quick check of the tightness of the four cyl bolts will clear that question up. If they are tight, then likely the gasket is not blown....however you find they are loose it will need looking at. As I said these gaskets are very thin and won't take much abuse if not clamped securely. The 49sp is an excellent saw IMHO and a real easy saw to work on. They are old and parts are hard to come by but there are many work-arounds. They are not heavy and handle great for limbing/firewood etc. They are quiet and smooth to operate with very few plastic parts.

We were out that way two Junes ago.....my daughter lives in Portland. We were there for two weeks and the wife and I traveled all about looking at stuff during the week while the daughter was working. Never been to the PNW before but would have already been back if not for the covid. Great state!!! We'll get your 49 up and running I'm sure!!
 
fullchoke

fullchoke

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Maine is a beautiful state, but I've only seen it in pictures. I've known a few people from Maine that described it as a lot like Oregon.
I feel good about the gasket fixing the 49sp. I like saws that are all metal and the 49sp has a vintage look and feel that I like. I sure hope it runs well. Jonsereds have a good reputation. I used to collect some old chainsaws, not to use or run, but because of the look with so many odd designs. My son wants to try to get some of them running, so we may try to tackle a few in the months ahead, since I retired. Appreciate the help! I will post back with an update when I get that new gasket.
Thanks again
 
Cantdog
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Maine is a lot like Oregon in some respects.....cool deep evergreen forests and rugged coastlines but I found Oregon to be much more diverse.....in an hour or two of driving you can go from mountains tumbling into the sea with a stunning coast to the high desert and then on to even taller mountains like Mt Hood, Crater Lake etc. and most anything in between. Really itching to get back out there!! Not to mention haven't been able to give the daughter a hug in almost two years!!
 
fullchoke

fullchoke

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Oregon is much larger than Maine and the Cascade Volcano's create a rain shadow, so there is a high desert to the east. Lots of different terrain and climate. I like the remote camping to the SE. The Steens Mtn's are incredible.
My daughter also moved west, but the Pacific kept her close. So I can still get my hugs thankfully!
 
fullchoke

fullchoke

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I ordered the new gasket and it fit correctly sealing the impulse so the diaphragm works. It doesn't fix the problem. In fact the saw won't start. It will pop initially, but then nothing. It acts like it's getting too much gas. The plug gets very wet. The low jet is slightly bent at the tip. Looks like it was tightened too much at one time. I tried starting it from screwed in to 2 turns out in 1/4 turn increments without any effect. We had a severe ice storm, worst one I've ever seen. Power was out for 5 days. Trees and branches down everywhere, power poles too. A transformer was still laying in the road yesterday a few addresses down. I have a lot of use for this saw, to say the least.
I'm thinking I may need a new carb for it, or new jets. Are parts available? Any ideas?
Thanks
 
Cantdog
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I ordered the new gasket and it fit correctly sealing the impulse so the diaphragm works. It doesn't fix the problem. In fact the saw won't start. It will pop initially, but then nothing. It acts like it's getting too much gas. The plug gets very wet. The low jet is slightly bent at the tip. Looks like it was tightened too much at one time. I tried starting it from screwed in to 2 turns out in 1/4 turn increments without any effect. We had a severe ice storm, worst one I've ever seen. Power was out for 5 days. Trees and branches down everywhere, power poles too. A transformer was still laying in the road yesterday a few addresses down. I have a lot of use for this saw, to say the least.
I'm thinking I may need a new carb for it, or new jets. Are parts available? Any ideas?
Thanks
Yeah the daughter has sent pics of trees down all over the place in Portland!!!
The needle should not be bent.......you NEVER screw in any needles other than to get lightly seated.....if the steel needle is bent from screwing in to tight your alum carb body is total junk!!!!! The initial needle setting should be one full turn out from just seated. The saw should start right up at this setting and you can tune from there. This particular carb was used on the 52/52E, 521 and 621 so it should not be hard to find one on ebay or the like. Tillotson HS 21D is the carb you want. My opinion would be you need to start fresh with another carb body and a Tillotson brand rebuild kit . Like this....

https://www.ebay.com/itm/3225468291...38679341&customid=322546829190_3&toolid=11000

Here is one.......

 
fullchoke

fullchoke

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We get a heavy ice storm here about every 12-20 years. I have seen quite a few, but this was the worst. They are normally a transitional event from a snow storm to plain rain. The Columbia River Gorge is the pipeline for the cold air to the east. This time was a little different, where it was 95% ice, about 1 1/2" of ice at my house. Huge cleanup on my 5 acres, which is about half in forest. I have other chainsaws I can use, but I was looking forward to the 49sp doing some work, seeing how much I like it.
Once I saw that bent needle, I knew I had problems. I didn't know for sure the carb was done, but I had always heard never to tighten the jets more than snug. I'm thinking that if it did quit in the cut, it got screwed up in the repair attempts. He told me he had the carb apart many times, and had given up on the saw. Thanks for the advice, I'll be looking for a new carb.
Thanks
 
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