Nissan 18hp 2-Strk Freshwater Flush

[abdiver7777]

I just purchased a used 18hp Nissan (18e) outboard motor for my Zodiac. I use it in salt water. When cleaning up I install a pair of those square rubber flushing device to a garden hose but I can't get water to flow unless I reach down by the prop and apply pressure to the device to force water into the motor. The motor pumps water just fine while in the water..........

Suggestions?

 

[DECK SWABBER 58]

Re: Nissan 18hp 2-Strk Freshwater Flush

Due to "muffs" being a one size fits all device,
cinch them tighter with something. This is
normal and probably not a fault with your
motor.

 

[abdiver7777]

Re: Nissan 18hp 2-Strk Freshwater Flush

Just curious........

Why would this happen? When boat is underway it should literly require a vacuum to induce water into the side mounted suction screens. The garden hose flush device literally has between 25-50 psi of pressure. It almost seems as the pump wn't pull this water into the case and it is relying on the water pressure to do this.

Anyone have the theory.........

 

[pvanv]

Re: Nissan 18hp 2-Strk Freshwater Flush

No, the flusher does NOT provide 25+ PSI. The water system at the house, ahead of the garden hose valve will have that, but after the ear muffs, the pressure can be as low as zero. And lots of air in there, too. Essentially, the water flows all over, but is not under any significant pressure, as it leaks out all over. Just holding a stream of water near the intake is about as effective as waving a "magic wand" near the water inlets ;-)

As Swabber said, you need a cinch strap to pull the muffs tight up to the water inlet of the motor. Pretty much every shop has a rig to do that.

Or, buy a Flushing Attachment, available at any Tohatsu/Nissan dealer, that screws into the motor.

 

[John_S]

Re: Nissan 18hp 2-Strk Freshwater Flush

I have an 18E and have not had any issues running on muffs. They should be a tight fit over the inlet. Water will squirt out, especially before you start the motor. Maybe yours were designed for large outboard or stearn drive? Also, if a new to you motor, and you don't have maintenance records, might want to change the impeller, just for insurance.

 

[Sea Rider]

Re: Nissan 18hp 2-Strk Freshwater Flush

3 Issues to consider for Tohatsu/Nissan engines :

1-Water pressure is escaping through ear muffs resting against tail, U frames are factory sloppy in most market brands, to better them: place muffs in central tail water intakes and mark frame (photo 1) place 2 small epoxic resin balls where marked (photo 2) let dry, with hand, close ears untill both slightly touches one another, place strap/belt on top of epoxic balls and tight/secure to this position (photo 3) will have a much better tighted frame against tail and much better water pressure going up.

2-If using unmodified muffs, place a piece of duct tape under the third water intake that's located under the cavitation plate to seal it as water exists also through third intake, sealing it will increase water pressure too.

3-The best method is 1 + 2 + 3 (Tohatsu flush adapter) conected to house water system, perfect water flow to engine (photo 4) With removed gas hose, flush untill engine on drops dead. If modifying muffs, ignore point 2 if house pressure is ok, flushing with 1 + 3 works perfect.

Happy Boating