Flushing the motor

[gcapehart]

Most of the time we run down the Penobscot River into the bay.  Generally it is clean fresh water(except at floods or extreme tides), then into a brakish mix sometime and then pretty clear saltwater. On the return 90% of the time our last eight miles +/- is the clear fresh water again. Any thoughts on any harm or when in doubt flush her out back home?   Gary

[GoneFission]

8 miles in fresh water should be enough, but a flush never hurts, especially if you have the hose connection on the motor that allows for a back flush.  Also you don't have to start the motor or use earmuffs - good for relations with the neighbors!

Welcome to the site and see ya on the water!

[gcapehart]

We have 30 acres and mother says don't sell so I fire up without complaints. But if the motor is not running do the thermostats let enough water up through the block, etc?  Gary

[Ben87]

If you can, flush no matter what, water is cheap and it only needs 5 minutes or so, at least my 2006 Mercury does.  The manual I have says I can flush with the motor off so I trust that they made the motor so that using the flush port takes care of things.  Now if you don't have a flush port and have to use muffs, you have to run the motor at idle or not much higher.

[gcapehart]

Yep I have to put the rabbit ears on each time. Have you ever changed transmission fluid? You always have to drain the pan by undoing all the screws. Engineers are great. Or, pardon the pun, "nuts'.  Gary

[beast819]

New to me.

I hear and read different methods of flushing the engine and was wondering what is the best method for my 1999 johson 90 hp. I found something that seems to be a valve kit that fits where your water sprays out of the engine when running. Would this be something to purchase and use to flush the motor. Also I see people saying you need to run the motor while flushing?

Please let me know what you guys think.

Thanks,
ant