Fresh water engine flush

[Peter J]

I have searched through past threads but can't see an answer to this question on engine flushing.

I have a 90HP suzuki, the dealer told me that I need not worry about flushing it out after use because that was for engines of 50HP and smaller because they had small narrow water ways, big engines had big water ways and did not clog up as much.

On my Powerboat course the instructor said to flush the engine after every use (they had 50HP engines)

Who is right?

If you do have to flush a 90HP engine how often should you do it?

Peter.

[ashbypower]

Hi Pete, We run 90's and flush after every use!! Even if they have larger waterways Salt crystals will and do build up to form a very tough layer.

WE also tell our students the same on their RYA courses.



Regards

Brian

[tue]

If you can try to flush your engine after every use or at least once a month to keep the water passages nice and clear. They may be wider but salt crystals will grow if left.

[Neal]

Peter i have a Mariner 75 and in the service manual it says
"after each use 1) Flush out the outboard cooling system if operating in salt or polluted water 2)Wash off all salt deposits and flush out exhust outlet of the propeller and gearcase with fresh water if operating in salt water"
Hope that helps.

[swginn]

Yep, flush out my Optimax whenever possible (its kept on a mooring, but I flush it out at the harbour/marina). The question you have to ask yourself is why not?? It only takes 5 mins!

[Clyde Rib'r]

I take it the salt crystals will clog up and cause the performance of engine to be poor??

[Pete7]

Eventually yes, the waterways fur up, however the water pump and termostats are 2 areas that salt crystals build up quickly and cause problems because they are very sharp and abrasive.

Whilst flushing with fresh water certainly helps be aware that after running a Yamaha 115 for a week on the upper Thames I was astonished to find salt crystals still on the termostats

Pete

[Peter J]

Thanks for the replies.

I found a half barrel that I can lower the prop into at home and I have taken to filling it up above the water inlets, just about up to the cavitation plate, and running the engine on idle while I wash off the rest of the boat (about 5 mins) does that sound like the right idea? Is 5 mins long enough?

Peter.

[-Dan-]

Originally Posted by Peter J

Thanks for the replies.

I found a half barrel that I can lower the prop into at home and I have taken to filling it up above the water inlets, just about up to the cavitation plate, and running the engine on idle while I wash off the rest of the boat (about 5 mins) does that sound like the right idea? Is 5 mins long enough?

Peter.

Flush Muffs would be a better idea.
Most engines let the flushed water out of the propeller, or al least out of an outlet that is under water. This means that the water in your barrel gets full of salt as well, and whilst this is better than nothing, there will still be a fair ammount of salt kicking around in comparison to flushing it with a hosepipe.

Dan

[timboli]

I always use flushmuffs,never sure how long to run it for though,any ideas anyone?