Need Help with Stihl 066 Rebuild

[huskihl]

Being an aftermarket jug, which are notorious for flat floors in exhaust ports, it may have caught a ring on the exhaust floor. Look for scoring or a small wedge of aluminum on the bottom of the ring pinning it tight to the piston

 

[PogoInTheWoods]

Any chance this particular 066 would happen to be a Red Light and you're leanin' it out fightin' the limited coil in your tuning?
And what oil are you using at 35/1 with the carb tuned on the "rich side'? That rascal should smoke out every mosquito in the county just idlin', let alone milling.

My money is still on an air leak.

 

[huskihl]

Any chance this particular 066 would happen to be a Red Light and you're leanin' it out fightin' the limited coil in your tuning?
And what oil are you using at 35/1 with the carb tuned on the "rich side'? That rascal should smoke out every mosquito in the county just idlin', let alone milling.

My money is still on an air leak.

Or maybe it was too rich and fouled the plug.

 

[NkyKelly]

Quit typing and pull the muffler. Then take pics of the piston through the exhaust port and post em.

We can't see your "feel and sound familiarity of the condition".

Some might take offense to that, but I got a chuckle out of it.

I will do just that. When it's on the mill its hard to get at everything. The reason I was typing and not taking pictures or working on it is that I can research and type on Forums while working

 

[NkyKelly]

Any chance this particular 066 would happen to be a Red Light and you're leanin' it out fightin' the limited coil in your tuning?
And what oil are you using at 35/1 with the carb tuned on the "rich side'? That rascal should smoke out every mosquito in the county just idlin', let alone milling.

My money is still on an air leak.

Definitely 35 to 1. It's the standard Stihl Oil in the Orange bottles. The Carb Limiters are still in there and it is set as Rich as it can be with the limiters. There is no smoke. I will get it on the bench in tomorrow and take a look.

Until I get definitive answers with pictures for you guys, I'll stop wasting your time. I'm impatient and want to move too fast.

Thanks again for all of the replies. I'll report back soon.

 

[NkyKelly]

Or maybe it was too rich and fouled the plug.

To be honest, I don't think anyone has asked for pics before. I actually had them from the previous instances. As I said, I will get them

 

[Adirondackstihl]

My bet is bad crank bearings & seals.
Accompanied with inferior AM parts.
An OEM piston kit can be had for around $50.

Send the saw
I'll rebuild it.

 

[huskihl]

Definitely 35 to 1. It's the standard Stihl Oil in the Orange bottles. The Carb Limiters are still in there and it is set as Rich as it can be with the limiters. There is no smoke. I will get it on the bench in tomorrow and take a look.

Until I get definitive answers with pictures for you guys, I'll stop wasting your time. I'm impatient and want to move too fast.

Thanks again for all of the replies. I'll report back soon.

Text is boring. Pics make this more like a magazine. Absolutely no offense meant by any of the above posts. Just wanna make sure you get it fixed right this time

 

[Deets066]

Definitely 35 to 1. It's the standard Stihl Oil in the Orange bottles. The Carb Limiters are still in there and it is set as Rich as it can be with the limiters. There is no smoke. I will get it on the bench in tomorrow and take a look.

Until I get definitive answers with pictures for you guys, I'll stop wasting your time. I'm impatient and want to move too fast.

Thanks again for all of the replies. I'll report back soon.

I would use a full synthetic oil for milling, I've noticed when running 32:1 that I need to richen up my tune from 50:1 every time.
If your milling with limiters in and runnin 35:1 your saw is probably lean anyway, not to mention any underlying issue.

 

[NkyKelly]

My bet is bad crank bearings & seals.
Accompanied with inferior AM parts.
An OEM piston kit can be had for around $50.

Send the saw
I'll rebuild it.

Well, the first time it wasn't inferior Aftermarket Parts for sure I get what you are saying though. I have the old Jug and will likely do what was suggested and Clean It up and get an OEM Piston. The biggest hurdle for me was having the right tools to do Vacuum test. So I either have to have someone rebuild it or invest in the tools suggested.

Text is boring. Pics make this more like a magazine. Absolutely no offense meant by any of the above posts. Just wanna make sure you get it fixed right this time

Thanks Kevin. I will start getting pics tomorrow.

 

[PogoInTheWoods]

I'll stop wasting your time. I'm impatient and want to move too fast.

Thanks again for all of the replies. I'll report back soon.

You certainly seem resourceful enough to get this sorted out as demonstrated by your replacing the top end in the first place. You also seem smart enough to take good advice when it's offered. You only waste our time when you don't take advantage of the latter.

Again, a vac/pressure test will tell you what you need to know regarding the integrity of the case and intake components and was suggested several times.

With any luck your AM top end is still intact and you simply have encountered another problem.

Lastly, those limiter caps need to go in order for you to be sure you have the range to tune the saw properly for your particular mix and operating conditions. And I'd go with a better synthetic mix oil (Stihl Ultra or similar) rather than the general stuff in the orange bottles as was already suggested.

Good luck with it.

 

[blsnelling]

Milling with limiter intact is a bad idea. I would take up AdirondackStihl on his offer. He'll fix you up right.

 

[angelo c]

My bet is bad crank bearings & seals.
Accompanied with inferior AM parts.
An OEM piston kit can be had for around $50.

Send the saw
I'll rebuild it.

I say take Jeremy up on this offer. He might not be the best looking guy at the ball but he can turn a pretty darn good wrench. And he likes Stihls too.
not sure how far from @wigglesworth you are but you might want to reach out to him in KY as well.
(Must be something with the name "Jeremy"...both very good wrenches.)
Hell @blsnelling is close by in OH as well. Brad has helped all kinds of people out in the past and has posted in this very thread as well.

plenty of help at yer finger tips here.

 

[mdavlee]

Brad is probably closest. Jeremy would fix it up right. With limiters, 35:1, and milling I'm betting its too lean.

 

[Adirondackstihl]

One other possible issue is the decomp valve!

 

[Deets066]

One other possible issue is the decomp valve!

I've had a leaky decomp, makes for hard tuning for sure.

 

[Adirondackstihl]

I've had a leaky decomp, makes for hard tuning for sure.

It could be the common denominator if it was used for all 3 top ends

 

[Adirondackstihl]

Bump

 

[PogoInTheWoods]