My stupid CS-490

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Bobby Kirbos

Scrounger of Cellulose Based BTUs
Joined
Sep 6, 2017
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Location
Echo, PA - just outside of Poulan
While cutting today, the saw ran well.

THEN

It started racing out of the cut. I would blurp the throttle a couple of times and the saw would calm down and idle nicely. I thought perhaps it was due to having the cold weather shutter open. So I shut the saw down and closed the shutter. Now it will not stay running. If I'm on the throttle it stays running, but dies as soon as I let it try to idle. Air filter on or off, shutter open or closed, same thing. Same mix that I'm using in all of my saws without issue.

It seems to me that it's going lean, but I'm not sure why it was fine after a blurp or 2. I did check and it's not the trigger not returning completely.

Clog somewhere on the low side on the carb? Air leak? I don't think it's the L screw setting - it ran fine at that setting. I hope the racing engine is relevant information.

So, any ideas what's wrong and where to look?
 
So, how well will a chainsaw run when there are 3 bolts holding down the jug, when there should be 4 bolts?

And, what are the odds that simply bolting the cylinder down will solve the problem ... without needing to pull the thing apart and put in new sealing goop?
 
Now we found out who was stupid. I'd give it a try putting in a new bolt and torqueing all the bolts good. If that doesn't work then off with the jug and reseal. Not too big of a job. Steve
 
I didn't do the base delete. It was done by the guy who I bought the saw from. That individual is no longer a member on this board. I think him trying to sell a low-mileage Makita that looked beat to hell gave us all of the information we needed. Unfortunately, I had already purchased this saw from him before that low-mileage Makita surfaced.
 
Too bad a quick run to Lowe's didn't get it done. M5x18 bolt, check. Thread locker, check. Stripped hole, FFFFFFFFUUUUUUUUCCCCCCCKKKKKKKKK!!!!!!!!!!!!!!!!!!

Unless you guys have a better idea, it looks like I will be retapping it for an M6.
 
Too bad a quick run to Lowe's didn't get it done. M5x18 bolt, check. Thread locker, check. Stripped hole, FFFFFFFFUUUUUUUUCCCCCCCKKKKKKKKK!!!!!!!!!!!!!!!!!!

Unless you guys have a better idea, it looks like I will be retapping it for an M6.
A timesert would help if you have another to do it.

That really stinks that you got screwed. I can’t recall how the bolts fit down through the head on the 490. Make sure the M6 bolt has enough head clearance to drop down through the fins to the hole. It may not need this, making a point.

Another thing is that the cylinder extension on some saws won’t allow the base to seal without a gasket. Another point I can’t recall.

A few pics that may help ya.

8EA82B0B-C902-40BD-95A6-5B481B85D304.jpeg 0A6F84AF-1C11-4251-9DD1-9879452C10B9.jpeg
 
Luckily it's the flywheel/carburetor corner and the fins don't go all the way down the jug. I can put the bolt in from the side, not needing to drop it in through the fins. I'll end up with a jug that is held on with different size bolts, but I'll have a saw that runs. Maybe I'll do some porting work on it while the jug is off.
 
GRRRRRRRRRRRRRRRRR

I took the jug off today. It's cracked through the base into one of the transfers on the side that was missing the bolt. :angry:

It looks like there was some sort of sealant smeared on the outside of the jug to seal the crack. Some people's kids.....

DOES ANYONE HAVE A CS-490 JUG FOR SALE? Used is fine as long as it's in serviceable condition.
 
GRRRRRRRRRRRRRRRRR

I took the jug off today. It's cracked through the base into one of the transfers on the side that was missing the bolt. :angry:

It looks like there was some sort of sealant smeared on the outside of the jug to seal the crack. Some people's kids.....

DOES ANYONE HAVE A CS-490 JUG FOR SALE? Used is fine as long as it's in serviceable condition.
That sucks Bobby. Got pics of the damage. As you know my local echo dealer closed shop so I'm no help on parts. I you decide it's not worth it I could use a parts saw. But I hope you get it fixed.
 
That sucks Bobby. Got pics of the damage. As you know my local echo dealer closed shop so I'm no help on parts. I you decide it's not worth it I could use a parts saw. But I hope you get it fixed.
Sorry Jim, I'm fixing it. I don't really know if the base delete is worth the hassle of a temperamental machine, so I ordered the $1 gasket.
 

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