The following tool have been developed for the 8/9.9 (211cc) and the 9.9/15 (305cc) four-stroke outboards.

341446 Valve Spring Compressor

Compresses valve spring in cylinder head for valve servicing - All models.

Click Here to search for 341446 on eBay

I am participant in the Amazon and eBay Associates program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to products.
Most, if not all, links are associated with this.