MS661C with a cracked upper AV mount

[Mike Canterbury]

Good morning! I purchased a used MS661C on ebay over the weekend. After winning the bid on it and doing more research to track down a replacement handle, I noticed the upper cup that has holds the AV bushing is snapped off from the clutch side of the crankcase. This was not identified in the description and the seller is going to take a closer look at when they get in today. They seem to be willing to adjust the price of the saw to account for the damage. My question is this, how much could I be looking at to have clutch side of the crankcase replaced? I am trying to come up with a ball park figure that I can use to negotiate the price down. I have read that this sort of repair should be conducted by a qualified technician and I trust the source of that information. I have the mechanical skills to strip the saw down to the crankcase, but splitting the case is outside of my capabilities or desire to do so. If anyone can offer some insight on this type of repair it would be greatly appreciated. Or, just be honest and tell me to ask for a refund and continue my search.

 

[rupedoggy]

whoops

 

[srcarr52]

I could probably weld that. A few pictures of it torn down would confirm if I can.

 

[Mike Canterbury]

I could probably weld that. A few pictures of it torn down would confirm if I can.

Ok. I'll get back to you once the saw arrives and it can be evaluated.

 

[andy]

You should return it.
I just did with a used 661 that had cracks on the clutch side.
Clutch side cracks were an issue with earlier 661's.
Local Stihl Dealer did not give me a through quote but said to expect upward of a $fiver to replace that side.....
Recommend you that you look for a later release date of the saw.

 

[Canyon Angler]

I can weld aluminum, but I'd run from that like the plague.

YMMV.

 

[andy]

The full wrap handle does not use that mount.
If there is no other cracking and you can get a really generous refund, you could get a full wrap and make a go of using it as is.
What else was damaged when that mount broke is the question.

 

[pioneerguy600]

Send it back for a refund. Stihl crankcase halves are seldom compatible as they are machined as a pair, replacing one half seldom matches up within specs. Can it be done, yes with extra machine work but not recommended.

 

[Mike Canterbury]

The full wrap handle does not use that mount.
If there is no other cracking and you can get a really generous refund, you could get a full wrap and make a go of using it as is.
What else was damaged when that mount broke is the question.

Andy,

Thanks for the input about the full wrap. The seller is providing a generous compensation refund because of this issue. With the refund, I have very little invested in it now. I found another post that states this is used as an AV flex limiter. Perhaps something could be fabricated and welded in its place to retain its function. I need to get the saw here and open it up to find out if there are any underlying issues. I should have it by this weekend and will know more at that point. The seller agreed to take it back if it is not satisfactory. It’s hard to give up on it so soon with so little money in it. Although, that could all change quickly the deeper I dig. I truly appreciate all the input guys.

 

[Mike Canterbury]

Send it back for a refund. Stihl crankcase halves are seldom compatible as they are machined as a pair, replacing one half seldom matches up within specs. Can it be done, yes with extra machine work but not recommended.

Im glad you brought this up. I would have assumed any replacement crankcase part would have fit. Thank you for your wisdom. It’s already on the way here. I’ll take a closer look at it once it arrives and make a final determination.

 

[srcarr52]

I can weld aluminum, but I'd run from that like the plague.

YMMV.

Well this case is made of magnesium.

 

[Canyon Angler]

Even more reason to run!

Seriously, what filler would you use for that? AZ92 ? Never tried welding magnesium...

Holy cow, that filler ain't cheap!

 

[2stroker]

Actually on this saw Stihl will sell just one side of the crankcase, separate part number in the ipl. With it's precision machining centers Stihl appears confident any half will match. Certainly wasn't always to case, no pun intended. Did some 066's years ago and had to leave the pins out and drew the cylinder up snug, without the piston, to get the cylinder mating surfaces to align. Spendy though, North of $180 for clutch side plus gasket kit at the minimum. Oh yeah, labor too.
2stroker

 

[andy]

Andy,

Thanks for the input about the full wrap. The seller is providing a generous compensation refund because of this issue. With the refund, I have very little invested in it now. I found another post that states this is used as an AV flex limiter. Perhaps something could be fabricated and welded in its place to retain its function. I need to get the saw here and open it up to find out if there are any underlying issues. I should have it by this weekend and will know more at that point. The seller agreed to take it back if it is not satisfactory. It’s hard to give up on it so soon with so little money in it. Although, that could all change quickly the deeper I dig. I truly appreciate all the input guys.

Well hopefully it works out for you. Wish you luck. The 661 is a great tool when it is
I'm far, far from an expert but have a recent experience that can be shared as wisdom.

.....Make sure you pull the clutch cover and the plate that covers the chain tensioner and look for cracks.
The earlier 661s had an issue that could come up on the clutch side crankcase..... cracks !

The Cause?..Some say user error... others say Stihl design mis-happery. Whatever the cause make sure you don't have the issue.
It will cause vacuum issues and poor run-ability and eventual failure. (probably soon)

Stihl made changes in later releases indicating... they discovered something they engineered needed a "patch".
I'd say that answers the question of whose feet the fault lies.
Your machine has a failure on that side already.. Whatever caused that av mount to crack may have brought the other "known" issue to the surface as well.

If you have anything that looks like this... send it back for sure.

 

[srcarr52]

Even more reason to run!

Seriously, what filler would you use for that? AZ92 ? Never tried welding magnesium...

Holy cow, that filler ain't cheap!

I weld mag all the time. AZ92A or AZ61A filler.

 

[Mike Canterbury]

Good afternoon! The saw arrived and I had a chance to open it up and inspect the power head. I found that the clutch side cover was indeed cracked near the bar studs also. I had my hopes up that I might be able to get away with a minor repair on portion of the case where the observed damage was. Unfortunately, the damage was much more significant than one could see without disassembling the saw. Furthermore, there are four broken cooling fins on the cylinder. That will need to be replaced too. I contacted the seller to start the return process. After completing an analysis of the actual cost to buy the parts, it does not make sense to keep this saw if I have some recourse to return it. Now I have some parts that i bought which need to be resold since I won't need them now. I was really hoping his was going to go in a positive direction. The saw appears to be fairly new aside from the damage that occured to it. Now I get to wait and see how the rest of this unfolds through ebay.

 

[andy]

Yikes... That's pretty nasty. But it sounds like you can chalk it up to experience without too much expense.

There are two really nice looking 661's in the AS classified at the moment. Just sayin

 

[Canyon Angler]

the seller is going to take a closer look at when they get in today.

So ... the saw was smashed but the seller played dumb? Remind me to put that seller on "ignore."

 

[Mike Canterbury]

Yikes... That's pretty nasty. But it sounds like you can chalk it up to experience without too much expense.

There are two really nice looking 661's in the AS classified at the moment. Just sayin

Andy,

The seller conceeded more money off the price of the saw so that I do not have to return it. At this point I only have $360 ($310 + 50 in shipping) in this parts saw. It is worth more than that if I parted it out myself. The rest of the unit looks fairly new. I had purchased some used handle parts, which are non-returnable for another $80. I've had a local forum member reach out to me and is willing to help with making the repairs. It has been a struggle going back and forth in regard to making this work out. I still believe it will be as good as new once the damaged parts are replaced. The idea of restoring the saw is exciting to me. I think it adds a lot more value in the long run to learn from this process. I assume it would be a parts saw for whomever takes possession of it in the future anyway if it was sent it back. I do agree that it would be a lot easier to buy one without all these issues. However, from a learning perspective, it would not be the same kind of experience. It has been a dream to obtain a saw in this class for a long time. I will certainly appreciate even more in the end.

 

[Mike Canterbury]

I tend to look for honesty and the good in people. However, in situations like this I I is hard to do so. I cannot imagine how this saw could have been considered as a running unit.