Jonsered Chainsaws

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It's been a long time since I did a recoil on a 361 (basically the same as a 'Lil Jon).If yop can keep the spring in place the rest is easy.If the spring pops out it's not that difficult to rewind them in the recoil shell.Take the screw out of the pulley & carefully lift the pulley off the shaft & spring.Put your new rope on winding it clockwise as the pulley would be mounted on the shaft.Put tension on as you would with any other saw.
 
The 49SP ignition has been kicking my butt the past couple days.I pulled the flywheel the other day to see why it wouldn't ground out & found the wire that comes from the switch to the condenser was broken.This is the weirdest set up for a kill switch wire that I've ever seen.Seems like they ran extra wires for nothing.All they needed to do was run the wire from the switch to the coil,simple,like on other saws.Instead they ran the wire to the condenser & then ran it to the coil,why?
I had another plate with good points & condenser,so I pulled the points plate off the saw & put the other one on,no spark.I guess the condenser took a dump.I even tried the other coil,still no spark.I had to pull everything apart again & put the original plate with points & condenser back on.One pull & it fired,2nd pull it was running.I haven't hooked up the switch yet,ran out of time today.As it was I put the flywheel & recoil back on while cooking burgers,Lol.
 
Finally have the 90 oiling! ThsteS a bit of a learning curve. Unfortunately I think that the o ring that seals the crankcase is in need of replacement after pulling the oiler and reinstalling a few times. It smokes pretty much constantly. Possibly it would burn off after a good run thought.
At least I know it will work now!

I’ll have to try to match up the o rings somewhere.

Does anyone happen to have a replacement set that they would be willing to part with……?

 
That might just be what's wrong with my 49SP.Fortunately I have another parts saw that I can take the oil pump out of & see if that makes a difference.
I got the customized switch hooked up today,had it in what I thought was the "On" position & pulled a few times & got nothing.I immediately thought the switch might be bad,but then tried the switch in the "Off" position & the saw fired right up.I loosened the nut up & turned the switch so it'd be right & retightened the nut.I tried putting a face plate on the switch,but then the nut wouldn't go on.The important thing is the saw has a switch that works & I didn't have to spend $17+ on one.I was going to post a pic,but it seems my new phone co.is about as bad as my old phone co.
 
I noticed in the 80 service manual there is a check ball in the oiler assembly but it does not show I the 90 IPL. I also do not seem to have it in the oil pump that I disassembled. Does anyone know if it should be there? I also see a very very small o/ring on the small spring here. This could very well be where the oil is able to pump back into the bearing are.

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I noticed in the 80 service manual there is a check ball in the oiler assembly but it does not show I the 90 IPL. I also do not seem to have it in the oil pump that I disassembled. Does anyone know if it should be there? I also see a very very small o/ring on the small spring here. This could very well be where the oil is able to pump back into the bearing are.

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You are correct. I looked in my 80 FSM and there is a pic of the tiny ball. In the IPL, I don't really see it. I'm not sure how important it is, but I tend to favor the pic in the FSM. I've had almost zero trouble with my 80/90 oilers....even my old original 80 which has had 40+ yrs of service with me.

What you circled in the last pic is not just a spring? Maybe that replaced the ball because everyone was losing it. I tend to think if everything was working at some point as it should, unless you lost something on disassembly, what you have is correct.

Kevin
 
Awright....couldn't stand it any longer...Had to figure this out!! Had a 90 oil pump already out sitting on the bench that I could fuss with. First there is no ball in later pumps that had the little o-ring type deal on the spring that you circled in red. I am going to try and explain what happens to the oil at what time in the pumping phase..... to start with the oil is being drawn into the pump from the tank when the plunger is coming out towards the crankshaft. The little 0-ring/spring seal is seated in the brass part allowing the vacuum to draw the oil up from the tank and through the two holes in the brass part. As the stroke of the plunger reverses and starts the compression phase the plunger passes the two holes in the brass part sealing the pump off from the tank. At the same time the little spring is compressed and the seal broken allowing oil into the pump body. Now the outside of the pump body has 5 o-rings on it....three large and two smaller ones. The three large ones seal the pump body to the case bore. Under the two small o-rings are four small holes, #62 in drill size, two in each grove covered by an o-ring.The first small o-ring (towards the crank end) is where the oil first goes under compression...the o-ring is lifted. oil exits the interior of the pump body and is then caught between the middle and the other large o-ring on the crankshaft end of the body. This is connected by a straight line bore to the oil gallery where the bar bolts on. Then the cycle begins again...so the small o-ring and the spring/seal deal are one way valves. But you may ask "what about the other small o-ring and the other large one" So the large one seals the pump body to the outside air. The small o-ring is also another valve ...this one operates the same as the first except instead of oil going to the bar this area between the middle large o-ring and the outer most one is vented directly back to the tank......this equalizes the pressure in the pump body and the pressure in the tank. If you are not oiling chances are the holes under the small o-ring on the crank end are plugged and not allowing oil out to the bar and/or the other ones are plugged as well not releasing the pressure in the pump body thus not allowing fresh oil to enter. If you are in fact sucking oil into the crank case you either have a blown crankcase gasket between the oil tank to where the counter weights run...or the o-ring that is on the end of the brass part has failed...If that o-ring is not sealing properly it could not allow enough vacuum to to draw oil from the tank too....those are the only two places that oil can get from one place to the other. Couple pics......showing the holes in the pump body and a oil and vent passages in the cases...they are offset from each other by about 3/8"...just the distance between the small o-ring groves. This is not a 80/90 case half but a 621....the design and method of operation are identical to the 80/90.


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Jonsereds also used a very small cotter pin up towards the top of the tank(under the muffler) to make sure pressure in the oil tank never got excessive.

The hole around the cotter pin will start to leak oil over the yrs and the fix is usually just to go to the next size cotter pin....lol.

Kinda goofy system, but seems to work. Not sure it's necessary....I epoxied the hole on my original 40+yr old 80 and never noticed any difference. I've been thinking about sanding down the epoxy to the mag and then re-drilling the hole....putting back in a cotter pin. Not sure it's worth the trouble as Robin shows there's a tank vent.

Kevin
 
Jonsereds also used a very small cotter pin up towards the top of the tank(under the muffler) to make sure pressure in the oil tank never got excessive.

The hole around the cotter pin will start to leak oil over the yrs and the fix is usually just to go to the next size cotter pin....lol.

Kinda goofy system, but seems to work.

Kevin
Yep ...a wiggle pin is what that is called....that's for tank venting to the atmosphere....what I was talking about is actually pump venting and where extra oil was returned to the tank and internal pressure released....if it could not be used to oil the B&C. A very complicated rig over all.....easy to see why they went to the later gear drive system.....
 
I think that the most likely spot that oil is leaking is at the small o ring at the brass section. Is smokes very low to none at idle but smokes like crazy as RPM increases which in theory would be at the same time that bar oil flow would increase. The saw is new to me. I’m not sure if the previous owner had it running anytime in the last decade or two. This is probably exactly why it was stuck on a shelf way back when
 
I think that the most likely spot that oil is leaking is at the small o ring at the brass section. Is smokes very low to none at idle but smokes like crazy as RPM increases which in theory would be at the same time that bar oil flow would increase. The saw is new to me. I’m not sure if the previous owner had it running anytime in the last decade or two. This is probably exactly why it was stuck on a shelf way back when
On the 90 oil pump I took apart the holes under the small 0-rings were clogged...every one. I would check this out on yours.....if those holes are clogged there is no where for the pumped oil to go but blow by the wimpiest seal.....which would likely be the one on the brass portion.
 

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