Engine flushing

Tue Aug 17, 2010 5:50 pm

I flush my outboard at home with muffs after every trip, I had read reports recently saying this
may not be the best was to flush the engine, due to inadequate water pressure from hose etc.
Just wondering how others do it, how long to you leave engine running for.
I am reluctant to leave it running too long on the muffs.
Any other methods or ideas appreciated.

Re: Engine flushing

Tue Aug 17, 2010 5:57 pm

I use muffs as well. As long as the engine is only ticking over and you have water coming out of the pisser youll be fine. Doesn't need to be run for too long anyway. For salt water flush a couple of minutes would be fine. I've run my Mercury 60hp like this for 10 minutes without any issues at all.

Kev

Re: Engine flushing

Tue Aug 17, 2010 5:59 pm

i flush with muffs for 5 to 10 minutes after every outing no problems, as long as you get a good flow from the tell tale you will be ok.
im sure the impellor would also act as a pump and draw water out of the hose :wink:
i have ran other engines in bins and barrels but it's a lot more hassle, unless you have a lot of space and can back up to a tank and drop engine leg into this for flushing.

Re: Engine flushing

Wed Aug 18, 2010 1:39 pm

Cheers for the replies lads.

Re: Engine flushing

Wed Aug 18, 2010 4:21 pm

I've used both systems i.e. in line flushing port and muffs - with the inline port the water used to come out the pisser even before I turned the engine on now with muffs no matter how high the water pressure its not enough to get round the impellor/engine and out the pisser before I turn it on. I wonder if there is a small amount of cumulative damage being done. That siad the seal you get over the intake with the muffs is impressive try moving them with the water running.

Re: Engine flushing

Thu Aug 19, 2010 12:13 am

There are a few engines that take water in under the cavitation plate as well as the two side ports . If your using the muffs there will be a very strong chance of an airlock leading to cooling problems.
Muffs aren`t a very reliable way of testing the impeller because the hose is forcing the water through the pump.
A barrel is better for that as the water is lifted by the pump only.The muffs are grand for flushing as long as you don`t run the engine up to full power.
I recommend running the outboard engine out of fuel to keep the carbs/pump/filter empty. *when running the engine dry always make sure you remove the fuel line and press the centre pin on the engine fuel plug to allow some air in and not damage the pump.
Hope this helps.

Re: Engine flushing

Thu Aug 19, 2010 2:02 pm

[quote="clinton marine"]I recommend running the outboard engine out of fuel to keep the carbs/pump/filter empty.[quote]

michael do you suggest running carbs dry every time even in summer :?: .
or as i do only when laid up for longer periods in the off season, when i would get out less often.

Re: Engine flushing

Thu Aug 19, 2010 2:54 pm

Some good info there lads fair play.
Just wondering what the idea of running the outboard engine out of fuel to keep the carbs/pump/filter empty.
Is it to keep the fuel out to prevent dirt etc building up.
I was always inclined to keep the tank topped up full to avoid any dirt in the bottom of tank getting sucked into carbs when fuel level dropped to low.

Re: Engine flushing

Thu Aug 19, 2010 11:51 pm

michael do you suggest running carbs dry every time even in summer :?: .
or as i do only when laid up for longer periods in the off season, when i would get out less often.

cormology wrote:Some good info there lads fair play.
Just wondering what the idea of running the outboard engine out of fuel to keep the carbs/pump/filter empty.
Is it to keep the fuel out to prevent dirt etc building up.
I was always inclined to keep the tank topped up full to avoid any dirt in the bottom of tank getting sucked into carbs when fuel level dropped to low.


Hi Lads.
I recommend running the fuel system dry for the following.
Fuel goes off very quick.
It turns yellow and looks like syrup
The carb bowls get a "varnish" like coating that blocks the jets.
Common rail injection systems can get blocked.
@ John. I would recommend running the fuel system dry when the engine is going to be idle for a month or more.
@Cormology. You should empty the tank at the end of the season because the fuel will go off anyway. I often see problems with stale fuel .
If your worried about sediment/moisture then get a good fuel/water separator with a clear base so you can see if there is contamination.

Re: Engine flushing

Sat Aug 21, 2010 8:49 am

Thanks for that good info - especially the tip about the centre pin, never thought of that.

Have you any opinion on aerosol carb cleaners as an emergency treatment?