View Full Version : Recommendations for possible LONG term OB engine storage?

UN Boats
06-03-2018, 09:29 PM
Hello, Seeking advice on best practices for months or possibly years of out of seawater storage of 150hp four stroke outboard engines. Six Yamaha and six Honda engines used in tropical saltwater environment for 2 years in a disaster response program. Vessels and engines now need to be stored in readiness until next disaster (usually typhoon) event. Are the standard winterizing/long-term storage procedures still effective in this situation? Ie: Can we be sure o-rings, seals, gaskets, etc. will not be cracking/leaking after possibly years of tropical conditions storage and not running regularly? Or better to set up monthly schedule of running engines with freshwater cooling supply?

06-04-2018, 09:06 AM
I'm not an expert on this by any means but many years of experience as an operator tells me that the more an outboard is run, the better it runs, and there are far fewer problems.

So, it would be much better to set up a monthly running schedule in a fresh water tank. Do not use just the flush attachment, but rather back each boat up to a large fresh water tank, drop the engine leg down into the tank to cover the intakes, and run it until it gets to operating temperature. It would likely be helpful to dump several gallons of vinegar in the tank in order to neutralize saltwater corrosion throughout the cooling system.

Also, change the oil over to Mercury or similar 25W-40 part synthetic or full synthetic with the NMMA FC-W designation. This oil is formulated specifically for outboard engines and will provide a longer-lasting protective coating to the various parts. When you change the oil, be sure to also change the oil filter.

You will also need to pay special attention to the fuel. Completely drain the fuel tanks and hook up each engine to a portable tank for it's monthly run. The fuel in that portable tank should be stabilized with Stabil, Startron, or similar.