Outboard Flushing Dumb Question

Yyjdennis

Active Member
I've attached a pic of the flushing connection on my new to me Honda 90 outboard. My understanding is that to flush the motor I unscrew this connection and attach a garden hose. Which side of the connection does the hose connect to, the rigid bit, or the hose?

Thanks,
Dennis

flush conn.jpg
 
Don’t start the motor when flushing with that hose. Unless Honda is different you need to use muffs to flush when you want to start the motor.
 
Buy the muffs from Walmart, Crappy tire or your local marine store, connect the hose to the muff and then put it around the water intake of the lower unit. Only start the engine when there's good water pressure. Tons of Youtube videos on this topic.

 
To flush with the Honda fittings connect the garden hose to the hose end on the motor. Don't run the motor.

To flush while running the motor either submerge the whole lower unit in a tub of water or use the clamp-on "muffs" as shown in @Ringo 's post above.
 
my dumb question, how does the thermostat get correct flush without opening and closing without temps?
 
my dumb question, how does the thermostat get correct flush without opening and closing without temps?
Those flush connections really only circulate water through the larger passages and do nothing for the thermostat. It's better than no flush at all I guess.
 
i was told by my yamaha dealer to hook a hose to the top flush hose with a saltaway dispenser set to water only and either put rabbit ears on the lower water intake or preferably put engine in stock tank covering lower intake. Turn water on BOTH locations and run until engine warms up. P indicator water gets warm. Then turn saltaway dispenser to saltaway setting and saltaway will clean all areas since thermostat is open. Run until saltaway in reservoir is gone and water there is clear.
 
Also, don’t put the hose on full pressure on the hose flush connection because you can cause a leak inside the motor if clips/hose clamps give out. Moderate pressure only. I read a story on THT where a guy caused serious damage to his motor.
 
my dumb question, how does the thermostat get correct flush without opening and closing without temps?
"Correct flush" no, but the thermostat has a 1/8" hole so that water will bypass and air doesn't sit in the chamber. In a verado for example the older thermostats did just that and caused an air bubble to cause an incorrect temp reading and then a temp sensor shut down. If it doesn't have one, drill one.
 
The reason you don't run the engine when using the hose flush port is because the impeller in the lower unit typically won't see enough flow and you can burn it out. So don't start the engine. I think the flush port may also bypass the thermostat. I was checking my ETEC manual and it doesn't provide a precise amount of time when flushing at the hose port, but if you flush with muffs it says flush for at least 5 min with the engine on. It doesn't state a reason, but that's likely the amount of time needed for the engine to heat up and open the thermostat.
 
I have this same Honda motor as the OP, bought new (well, the 100 hp version) and can confirm 100% that you attach to the hose for flushing and do not run the motor. I think other posts have already established that so just adding that is the info direct from the manual. I'll add my own question/problem to the debate about flushing that way or running on muffs though. I get inconsistent flow when flushing on muffs. Sometimes it seems to work fine, other times I get nothing from the pee hole. Have gotten the high heat alarm a couple times flushing with muffs and running.

So lately I have just been doing the passive flush through the hose fitting. I figure a passive flush with Salt Away is better than potentially overheating the motor on a regular basis. Still, for the reasons mentioned here I'd prefer to do a running flush if I could do it consistently. May try the tub of water thing but its certainly less convenient than muffs. Nothing has changed with my muffs or my water pressure, and I have no problems with the motor pissing actually on the water, have never overheated even running on step for 1.5 hours straight etc. Just seems to be on the muffs.
 
Thanks everyone. I am storing the boat in the water for the winter as I've gotten a chance to sublet a slip at a good price. So, I think I'm just going to do the flush connection thing as it's better than nothing and putting muffs on isn't really possible.
 
I keep my boat in a marina for 7 months a year and make sure I flush with the connections as soon as I hit the dock,so both kicker and main are still hot and thermostats are still open. Bonus having fresh water hose and power in front of my boat,not all marina's have it.
 
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