Water Pump Flushing Attachment Merc 1500

[Zac Penn]

My 1974 1500 has a flushing port on the water pump that is 5/8" x 11 thread, but i can't find an attachment that will work with that thread. Does anyone know where I can find something like that that can be adapted to a garden hose thread?

 

[bruceb58]

Any reason you wouldn't want to just use muffs?

 

[emckelvy]

Any reason you wouldn't want to just use muffs?

Because his L/U is a morphodite and does not have a side intake; it intakes thru holes in the trim tab, 'cause it's a circa-1962 unit.

This is what he's looking for: http://store.oldmercs.com/product_p/24789a1.htm

Note that they DO NOT recommend running the motor when using this flusher, the reason for that is the flusher's water flow path is on the discharge side of the impeller, and there's no guarantee that enough water to keep the impeller from burning up will flow into the pump.

Many Many Moons ago my Dad had a Reinell with a 120 Mercruiser and he would always flush with that style of attachment, and I recall that he would run the engine. We found out that wasn't a good idea, when the engine overheated coming back from a trip to Seattle.

We were stuck in the rip tides between Bainbridge Island and Blake Island, and it was getting dark.

Fortunately a fishing boat saw us waving and towed us to shore. Talk about learning the hard way. The impeller was cooked!

HTH...........ed

p.s. if you want to run the motor to test it out, it'd be way easier to find a big blue plastic water barrel (or whatever), slip it under the motor, and fill it up to cover at least halfway-up the exhaust tower.

 

[Zac Penn]

Actually my motor is 1974 1500 and it does have the side inlets so I can easily use the ear muffs. My reasoning for the flushing adapter is so that when I come home at night, after a long trip I do not want to wake up the neighbors with my motor. I would also like to be able to pull into a city marina for the night and use their water hose to flush the motor while it is still in the brackish water. I have also thought about bringing a fresh water container with me to the boat ramp and a water pump to flush out the motor before I make a long trip back to the house.

I will not be running the motor when I use the flushing port.

Thanks for the link to that flushing port. The picture makes it seem like the threaded section is smaller than 5/8" x 11 but I will contact the store to make sure before ordering.

 

[emckelvy]

Sorry, I thought yours was the 1500 with the older L/U! Too many posts to remember I reckon! :facepalm:

So I'll retract the "morpodite" description, you have a Wonderful 1500 with a lovely L/U! :lol:

Your comment jogged my memory; the old, old engines had a metal screw that went into the 3/8" flushing port on the side of the water pump base.

Later models that still had the flushing port, had a larger, plastic screw with a rubber gasket on the end. But I don't recall the hole in the pump body being threaded.

But, and again I'm pulling this from some very old brain cells (!), the flushing hole in the pump body was 3/8" and could be tapped-out to fit the "retro" flusher.

Another thought, get a 2nd flushing screw; drill and tap it to accept the flusher; remove the "normal" flushing screw and install the plastic "adapter" when you want to flush.

For greater durability, you might want to install a Heli-Coil in the plastic. Or, just permanently screw the flushing rig into the plastic "adapter" and screw the whole mess into the flushing port.

One more thought, that plug isn't a lot to work with; if you can find the correct-sized bolt & thread-pitch, you can drill that, thread it, then screw the flusher into it. Since you're planning on using it a lot, you may find the OEM plastic plug won't hold up to the use.

The most Awsome adaptation would be to install a 3/8" Heli-Coil in the pump base, this would directly accept the motor flusher. You could probably do it in place, but it'd be hard to contain any plastic shards from drilling-out the pump base. I would want to remove the base, to make it easier to work with and to ensure this would actually be feasible.

BTW you can just make out the flushing hole in the pic below; there are 2 water pump bases listed for your motor, one without a hole, and the 49-69222A1 pump body with a flushing hole.

I don't see any threads in that pic and I can't recall ever seeing a flusher that would screw into the larger threads in the gearcase. Interesting mystery!

Hope that all makes sense! Let us know what you come up with...............ed

 

[Chris1956]

Zac, I believe you are overthinking this. It is perfectly acceptable to wait until the neighbors wake up, before flushing your motor. Also, not flushing while in a marina overnight is fine too. Your motor is already older than most actresses and supermodels. If you don't flush it promptly, the effect will be negligible. Heck, the supply of parts will likely be exhausted before the motor is damaged by delayed flushing.

Just my thoughts!

 

[Zac Penn]

Sorry, I thought yours was the 1500 with the older L/U! Too many posts to remember I reckon! :facepalm:

So I'll retract the "morpodite" description, you have a Wonderful 1500 with a lovely L/U! :lol:

Your comment jogged my memory; the old, old engines had a metal screw that went into the 3/8" flushing port on the side of the water pump base.

Later models that still had the flushing port, had a larger, plastic screw with a rubber gasket on the end. But I don't recall the hole in the pump body being threaded.

But, and again I'm pulling this from some very old brain cells (!), the flushing hole in the pump body was 3/8" and could be tapped-out to fit the "retro" flusher.

Another thought, get a 2nd flushing screw; drill and tap it to accept the flusher; remove the "normal" flushing screw and install the plastic "adapter" when you want to flush.

For greater durability, you might want to install a Heli-Coil in the plastic. Or, just permanently screw the flushing rig into the plastic "adapter" and screw the whole mess into the flushing port.

One more thought, that plug isn't a lot to work with; if you can find the correct-sized bolt & thread-pitch, you can drill that, thread it, then screw the flusher into it. Since you're planning on using it a lot, you may find the OEM plastic plug won't hold up to the use.

The most Awsome adaptation would be to install a 3/8" Heli-Coil in the pump base, this would directly accept the motor flusher. You could probably do it in place, but it'd be hard to contain any plastic shards from drilling-out the pump base. I would want to remove the base, to make it easier to work with and to ensure this would actually be feasible.

BTW you can just make out the flushing hole in the pic below; there are 2 water pump bases listed for your motor, one without a hole, and the 49-69222A1 pump body with a flushing hole.

I don't see any threads in that pic and I can't recall ever seeing a flusher that would screw into the larger threads in the gearcase. Interesting mystery!

Hope that all makes sense! Let us know what you come up with...............ed

Thanks for the compliment!!!!!!! If only my wife liked my L/U as much HAHAHAHAHA

Yes I do have the larger threaded plastic plug like the one in your first picture. I already tried to drill out and tap the old plug to accept a 1/4" MPT fitting but you end up with a VERY thin layer of plastic remaining after the drilling and finding a way to secure the plug while tapping is very difficult.

I was hoping I could find a 5/8" x 11 Nylon threaded rod that I could drill and tap but no such luck locally.

What does everyone think about flushing the motor from the pisser hole on the lower cowling? If I remove the plastic plug from the L/U and insert a barded fitting into the pisser outlet I should be able to flow the water backwards out the water pump correct?

 

[Zac Penn]

Zac, I believe you are overthinking this. It is perfectly acceptable to wait until the neighbors wake up, before flushing your motor. Also, not flushing while in a marina overnight is fine too. Your motor is already older than most actresses and supermodels. If you don't flush it promptly, the effect will be negligible. Heck, the supply of parts will likely be exhausted before the motor is damaged by delayed flushing.

Just my thoughts!

Really???? Like i have said before this is my first real venture into outboards (and of course I went with an antique, because I love chaos) and I have always heard TERRIBLE things about saltwater on freshwater motors. I do not intend on keeping this boat/motor combination forever but I do want to keep it as healthy as possible. Having 150 psi on all six cylinders is the only reason I bought the motor so i would hate to mess anything up.

 

[emckelvy]

eBay to the rescue! Package of (1) nylon 5/8-11x1" nylon bolts, $10.11 shipped:

http://www.ebay.com/itm/251823346938

Drill a hole thru the bolt, drill and tap the head to fit flusher threads, and away you go!

 

[Zac Penn]

Oh you are the man!!!!!!! I just ordered them and I will post pictures once I get it finished.

 

[emckelvy]

Very Cool! Will be interesting to see how it turns out.

One crazy thought I had, was to maybe shorten the bolt a bit, and plug the hole in the bolt head with a 3/8" bolt & sealing washer, such that you'd only have to remove the 3/8" bolt to screw the flusher into the nylon adapter.

Install a Heli-Coil in the bolt head to keep the threads from wearing out. Or maybe threads in the nylon will be tough enough as is. Heck, with 10 of 'em, you'll have plenty to experiment with.

Have a good one.......ed

 

[Zac Penn]

No Title

I received my Nylon bolts today and started this project. I went to my local Ace Hardware to find the NPT bushings I would need to make this work. I already had a female garden hose x 1/2" FNPT fitting so I needed to get a 1/2" MNPT x 1/8" MNPT but that didn't exist. They also didn't have a 1/2" MNPT x 1/8" FNPT fitting so I had to use multiple bushings and then an 1/8" MNPT nipple to make my final connection to the nylon bolt.

I hooked it up to the flushing port and turned on the hose and she was a pissin good. So now I can flush the motor out without having it run and annoying my neighbors. The whole thing cost me about $30 if you include the garden hose fitting that I already had.

It is too bad that the water pump isn't a little bit higher so the flushing port would be above the cavitation plate. If it was up higher I would just leave a standard nylon bolt in the flushing hole while I was running and since it would stick out about 3/4" from the motor I could just grab it with my hands and unscrew it. This would eliminate the flathead screw driver from the equation but now I am just getting too lazy

Thanks again for the ideas,
Zac