Don't know why I never thought of this

[km1125]

I have raw water cooled engines, so every year I have to deal with the drain plugs. Well, I probably don't REALLY need to, if I wanted to flush enough coolant through there to make sure the blocks got enough. However, I always do. I used to put the antifreeze in first, then pull all the plugs out and recover most of it, but it would also let me know how much antifreeze made it to various parts of the engine and manifolds. Then, I migrated to pulling the plugs first, draining the water, then putting them back in and running the antifreeze through.

The 'outside' plugs on the block are hardest to get to. The fuel tanks are outboard of the engines, so to get to these plugs you have to lean over the engine and reach down and 'feel' for where the plug is and unscrew it blindly.

So, this year I changed the plugs out for hose barbs, and ran a hose between them. I put a hose-barb splice in the middle. To drain the block all you have to do is pull the splice apart, which is right near the front of the engine and both sides drain. Because I used a straight hose barb on each side, you can run a coat hanger or other flexible wire up the hose to make sure nothing (like rust) is plugging it and preventing any draining. It's also so much easier to re-capture if I need to... just put the hose ends in a bucket or tub.

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[Midnightsun]

That will probably be handy in your application.

A couple of things to watch though. Make sure those fittings cannot get too hot as the vinyl hose may not like it and you could have a lot of water to deal with. Another issue is there is always a little sediment and sometimes rust in there so you do want to poke a wire into the hole to open the flow which can get completely blocked.

[km1125]

Source of the post That will probably be handy in your application.

A couple of things to watch though. Make sure those fittings cannot get too hot as the vinyl hose may not like it and you could have a lot of water to deal with. Another issue is there is always a little sediment and sometimes rust in there so you do want to poke a wire into the hole to open the flow which can get completely blocked.

I just used the vinyl reinforced for now because you can see though it and see the 'cleaning rod' to make sure it gets all the way to the end. I ended up making all the hoses the exact same length so that the 'cleaning rod' would be the same no matter which one you are checking/cleaning. My thermostats are 140 and just hit that at cruise. Anything less this time of year and it's hard for my engines to get up to 140 with all that cold lake water.

[Midnightsun]

Looks like you got the bases covered. Nice mod.

[Viper]

I like it KM. The only thing I see being a pain is getting the hose off the barb coupler. I guess in the grand scheme of things, it's easier than crawling around the engine or blindly feeling your way to drain the one side. It you take the same type of fitting you're using at the block end and put another one at the draining end, you could cap the end off with a brass cap instead of trying to remove the hose off the barb. This set up is used to drain oil pans in some applications.

[RGrew176]

If you find a system to do things and it works out well then keep it up. Looks like you have a great way to get the job done.

[km1125]

HA!! Well, a bit of a story to tell here. I put these hoses on just to make the winterization easier for tomorrow morning, as I get hauled out at 'first thing'... 8:30 AM.

But today was a nice day. A VERY nice sunny day.

So in the midst of getting everything else done (winterizing the potable water, etc)... we decided to take a cruise out on the lake. Stopped at the gas dock, put some Sta-bil a a bit more gas in the tanks, pumped out both waste tanks and hit the lake. It was SOOOO nice. The lake was awesome, clean, blue-green color and just a little ripple.. NO CHOP. I was out there just doing little circles running over my own wake. Got the bow pointed up a bit and drew the last few gallons of water out of the potable tank.

I had been piloting on the bridge, but it was pretty chilly in the wind. Went to the lower station and was checking all the guages and stuff, when I -for some reason- decided to pop the hatch and take a peek at the engines.


HOLY SH!!!!T !!! There' a FOOT of water in the bilge!!!!

I quickly slowed the boat down to near idle to get a better look. Got the hatch out of the way and wedged so it didn't fall over.

I put the bilge pump in manual, because I couldn't tell if it was running or not... it was underwater. Couldn't see any obvious signs where the water was getting in... looked at all the thru-hulls and they looked good. Looked at the pumps and the hoses and they all looked good too.

Water didn't seem to be going up or down, which I thought was a good thing... at least it's not getting worse.

Quickly tried to raise the USCG on Ch 22... no answer. I was about 2 miles from their local station. Went back to the bilge and looked around some more. Seemed like I could detect some swirl around the raw water pump on the port engine, so I shut that down. Tried the USCG again on 16, and no answer there either. I had responded to TWO folks this morning for radio checks many miles away, so I didn't really think I had a radio problem. I also wasn't calling 'pan-pan' or 'mayday' either, because I wasn't really convinced I was there yet. If worst came to worse, we still had the dingy o the swim platform and I could have launched that literally in seconds.

With the water still and clear, now I could see though it... and sure enough, the hoses that I just put on had some loose on the coupling in the middle. Checked Starboard and it was the same thing, so I shut that engine down too. Found some clamps and put them on. I had ty-wraps on them and had tested them several times, but when we were on the lake I was pushing the throttles up MUCH higher and there might have been a bit more pressure on the raw water side (what kind of max pressure do you typically see there???)

With both hoses secured, I started the engines to give that bilge pump another volt or two to work with. Took a bit but the bilge pump finally evacuated it all. After I got back, I took some measurement and calculated it was about 1600 lbs of water in the bilge.

Was not really planning on rinsing out the bilge prior to putting the boat away, but at least that task is done!!

[bud37]

Remember you have a thermostat controlling water thru the block so you will get pressure in there from expansion, could be as much as 10psi or more......I thought I read you had valves at the block connections ?

Thanks for posting the result, good on you......

[km1125]

Source of the post Remember you have a thermostat controlling water thru the block so you will get pressure in there from expansion, could be as much as 10psi or more......I thought I read you had valves at the block connections ?

Thanks for posting the result, good on you......

No valves. There was barely enough room for the hose barb on the port side of each engine... the drain is right next to the engine mount.

Years ago I was told not to do valves as there is a tendency for them to open up by themselves. I thought about trying to use some safety wire on them, but that's getting into more work than just the drain plugs themselves, so I just stuck with the plugs.

There's always some bypass on the thermostat, so it shouldn't be able to build much pressure due to heating and expansion. I was guessing about 10 or 15 PSI and because the hose barbs were so hard to get apart I even thought they might be OK without even a ty-wrap, but I put on on anyways.

[Viper]

Hoses should always be mechanically secured. Never even thought of bringing that up, just assumed it would be clamped. We've all learned lessons the hard way over the years. Thanks for sharing KM and glad you caught it in time, it could have been so much worse.