Stihl MS290 Nightmare Rebuild Questions…

Alaskan Stihl

Alaskan Stihl

ArboristSite Member
Joined
Jul 30, 2021
Messages
74
Location
Alaska
Hey! It just dawned on me! I looked at the old a Stihl Cylinder (the one that I removed) and it has the same issue as the Aftermarket does (the Ridge in the Seal Saddle is ground flush…missing).

Here are a couple pictures of what I am talking about…(Note: You might have to view the thumbnails to get a more clear image).
The first picture shows the “Outer Ridge in the Flywheel Side. As mentioned, it keeps the Seal in place and keeps it from popping outward. The other picture is if the Clutch Side and has no ridge. The Stihl Base Pan is manufactured the exact same way (ridge on flywheel side…no ridge on clutch side).

My guess is that…on my (2) Halves (Cylinder =Aftermarket and Base=Stihl)…are not a perfect round fit. Or moreover, the two holes for the Seals don’t match up perfectly….either case causes the Seal to Pop out when I tighten it up to cinched.

I guess I will find out just how bad things are after everything cures tomorrow and I run the PSI/VAC Test…fingers crossed. XX

As mentioned, that Bar Oil Pump has a “Inner Ridge” that acts as a barrier to keep the Seal from popping out when the Base Bolts are tightened….not to mention that it is bolted in place to keep the seal in check as well.
 

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Alaskan Stihl

Alaskan Stihl

ArboristSite Member
Joined
Jul 30, 2021
Messages
74
Location
Alaska
Jasonrkba: AHA! That tool makes sense! I see how that hook end allows the end use to pop out the limiter stop…
Problem is….price of course (shwang) there goes another $25 bucks!

I will have to order one off of eBay, since I would only catch grief from trying to purchase such a secret and controversial tool from our local Stihl Parts Store! HaHa!
 
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