I was trying to find out some information on how best to descale an outboard motor, though was finding very little information available. Then I found a product called Rydlyme Marine Descaler available from www.expresslube.co.uk , which worked a treat so I thought I would share some pictures of how I did it. My outboard is a Yamaha 8hp 2 Stroke which is very old and has been with "Folly" since it was purchased. The engine has been serviced regularly and does not over heat, though the engine does sit in a well and never gets flushed through during the season.

The first thing I did was to remove the lower leg, as I was going to change the impeller as part of the service. I then attached a tube to the inlet pipe with a jubilee clip, the other end was attached to a 12v submersible pump. I also attached a small pipe to the tell tale so as not to loose descaler during the process. I then mixed up 2L of descaler with 1L of water in a bucket, which was then placed under the engine with the 12V pump in it. The solution was then circulated for 1.5 hrs. Once completed I then flushed the engine with a hosepipe.

Now when the engine is running the tell tale is so much stronger, and the engine runs like a dream. I hope some of you may find this useful.