Engine flush attachment?

[Coastal Rick]

I was looking at my outboard and there is a screw on the lower unit with "flush" marked on it or next to it on the LU case. In the manual or the expanded parts diagram I've seen it referenced as an attachment point to flush the outboard without running the motor. Some kind of attachment goes there and i suppose a hose goes to that. I always have lots of trouble getting the flush cups to pump enough water - I have to squeeze them tight or water stops running out the telltale - so an alternative would be nice.

Anyone know if the parts are available, have you used it or heard of it being done, does it work? I'm running in saltwater about half the time so a post-run flush is typical. Thanks.

1973 Merc 20HP s/n 3674653

 

[Chris1956]

Re: Engine flush attachment?

I have not see the flush adaptor for years. Can you use a standard flush device on that motor?

 

[Coastal Rick]

Re: Engine flush attachment?

Hi Chris,

I am using the round muffs right now, and they slip off and don't seem to hold tight enough to pressure the water up into the impeller. If I squeeze them by hand for a better seal, water goes where it needs to and up and out the telltale.

Is there another kind of attachment for that flush port? A standard kind? Or something else you had in mind? Please share if you know of anything. Thanks,

Rick

 

[sschefer]

Re: Engine flush attachment?

I have not see the flush adaptor for years. Can you use a standard flush device on that motor?

Small saltys without a divider plate or head cover plate adapter have them. If I remember correctly their 1/8" npt. You can make an adaper with a 3/4" female hose adapter x 3/4 MIP then 3/4 FIP x 1/2 FIP bell reducer, a 1/2 MIP x 1/8 FIP reducer then a 6 x 1/8" MIP nipple. You are not to run the engine while flushing because there will not be enough volume to support cooling.

As a side benefit, the adapter works great as a pressure nozzle too.

 

[bob1340]

Re: Engine flush attachment?

Small saltys without a divider plate or head cover plate adapter have them. If I remember correctly their 1/8" npt. You can make an adaper with a 3/4" female hose adapter x 3/4 MIP then 3/4 FIP x 1/2 FIP bell reducer, a 1/2 MIP x 1/8 FIP reducer then a 6 x 1/8" MIP nipple. You are not to run the engine while flushing because there will not be enough volume to support cooling.

As a side benefit, the adapter works great as a pressure nozzle too.

That is cool. I just got a 1969-1970 7.5 and it has the flush on it. That sounds handy if I ever do the salt water thing.

 

[Coastal Rick]

Re: Engine flush attachment?

Hey that sounds like something I can put together. It would be so nice to let it flush out while I'm putting stuff away, without having to constantly fiddle with the muffs.

I'll try to post a picture if I can get the thing put together.