Small outboard fell in the river - help!

[Kehaar]

My Mercury 9.9 4 cycle fell in the river (brackish water) and was submerged for several hours. I have retrieved it, removed the cowl an sprayed it off with fresh water. Do I attempt to start it or should I change the oil, oil filter and maybe spark plug first?? Changing fluids may result in it sitting another day or so before I can do that. What to do? Thanks.

 

[PascalG]

Definitely change the oil right away. DO NOT START IT with contaminated oil. Pull the plugs and pour diesel RIGHT AWAY in the cylinders to prevent corrosion from starting, crank it around a bit and pour more diesel Fresh water isn’t as bad as salt which only gives you a 24 hour window to save the motor. Soak everything with WD 40 or Bowshield.

 

[Kehaar]

Thanks. How long can it sit before I pour diesel in? Not readily available. Will be about 10 hours+

 

[psalzer]

S I would think any kind of light oil would do. You just Ned to inhibit rust or corrosion. Marvel Mystery Oil comes to mind, or plain 30w diluted with a little gasoline

 

[JVM225]

Here is a link to a pretty good YouTube video. The two differences with your motor are.
1. You’ll have to drain your oil because it’s a 4 Stroke.
2. You don’t have to drain your tank because it’s not integral.

https://youtu.be/RBxN5vXTVzc

 

[Kehaar]

Thanks for these. I found some diesel. It was amazing how much water came out before the oil started to flow when I pulled the oil drain plug.

 

[WALSHIE]

After changing oil...With plugs out, keep pulling the start rope, until no water comes out. Make sure to keep cylinders lubricated.

Clean plugs and clean any electrical connector. If you can get to the stator, clean that too with wd40. Expect to replace this later, maybe next spring.

Once happy, add fresh gas and start it, keep an eye on the oil, if milky, change and repeat until clear. Keep an eye out for milky oil.