I would add some comments.   I ran at least 5 big bore Continentals to rebuild with those boat anchor TCM starters and never had a adapter problem using 15w-50, W100 and W80 and the "Plus" versions of Aeroshell oils.    I have not heard of this issue with until I got the Legacy.  The problem only appears with the advent of the lightweight geared starter.   The ISKRA is now hopefully gone from new production and the SkyTec versions have been modified to use a clutch and avoid the gearing issue that is the problem according to rebuilders of the adapters.

Mike is right about "aggravating" but it is not the cause.  I had the slipping problem on the Legacy and changed oil and added some Camguard I won at Oshkosh.   It immediately stopped spinning on start but had been slipping just prior.   I believe the W100PLus has the similar ingredient as Camguard and is designed to prevent corrosion for up to 2 weeks of non-use.  I stopped using 15w-50 many years ago and have much better overall wear numbers on my oil analysis.

The use of these oils/additives does not create the starter adapter problem.  However, it will make the slippage so much more evident especially if the battery gets weak, the engine is tough to turn over and the wear is getting severe on the adapter.  I believe going away from the PLUS and additives and semi-synthetic might buy some time on a slipping adapter.

No oil is going to fix the problem if it already exists.  I'm currently very happy with the W100 and W100Plus oils in Florida, W80 and W80Plus in colder climates and the TCM old style starter on the Legacy and I have the benefit of what appears to be a very fast RPM start using the TCM starter--probably double what I was getting from the failing ISKRA.
Paul
Legacy
Spruce Creek

On 2012-04-24, at 9:46 AM, Colyn Case wrote:

> Right about when Adam was talking about starter adapters I was talking to Mike Busch about oil.
> In the attached recommendations he mentions that Aeroshell multigrade 15W-50 has "history of aggravating TCM starter adapter slippage", among other issues.   As more than one on the list has had starter adapter issues in the last couple years I thought I would pass this along.