3.0 Cooling Hose Question

[Grady in Texas]

Hi - New here and I have some confusion about one of the cooling hoses. The boat is at storage or I'd go look myself - if I need to order something I like to do it in time for the weekend. The boat is a 2003 Sea Ray 176, owned since new, with a Mercruiser 3.0 0M384901.

Yesterday, while changing the fuel pump, I dropped a bolt in the bilge and while fishing it out from the exhaust side, I noticed a 3/8 ID hose with a broken off (rusty) barb and hose clamp dangling loose near the rear of the engine. The other end of the hose starts on the top of the engine cooling system (mid-engine) and when the engine was running (briefly) water pumped out of the hose end. The hose has not been disturbed so it must connect somewhere on the exhaust side towards the rear of the engine (based on the routing and length of the hose).

I assumed it was connected to the fitting that comes out of the bottom of the exhaust manifold. I removed that fitting (9/16" wrench) which is hollow brass but there is no sign it "rusting" or snapping off. It looks like it might be some type of disconnect fitting. However, looking at engine diagrams today, the filling is described as a bushing/plug for draining the manifold. (I'm 99.9% sure it's original, but I don't know if it is a Mercruiser fitting or a Sea Ray fitting.)

Any idea where the hose terminates and/or what the fitting should look like? Thanks! Grady

 

[Bondo]

I assumed it was connected to the fitting that comes out of the bottom of the exhaust manifold.

Ayuh,..... Welcome Aboard,..... Merc has tried some stupid Ideas for drainin' the manifold, 'n block,.....

Does the hose go to the block drain, just below the manifold drain,..??
Is there another brass plug in the block drain,..??

If by chance this is 1 of the nitwit single point drain systems,......
Junk the entire thing,......
Yer corner hardware store will have plain ole brass 1/4" pipe plugs,.... (9/16" wrench)
Buy a couple, 'n use those,.....

When ya drain it, you can poke a nail or screw in there to knock the sand, mud, 'n rust outa the way, to let All the water drain out,.....
No freeze busted blocks that way,..... Air don't freeze,.....

 

[Grady in Texas]

Ah, Yes, it has some kind on super drain which I've never needed because I'm in SE Texas. The plug in the block looks OK and it doesn't appear that the hose goes there which is why I ass/u/me-d it went to the manifold fitting.

So is it OK to loose the hose and and just plug both ends off separately or does the water need to circulate? Thanks!

 

[TurtleTamer]

Raw water- or freshwater-cooled? If using a heat exchanger for the engine then your hose may have come from the riser, connected at the back of the riser where it's not easily seen. If you're raw water-cooled then it's possible someone rigged up something on your manifold drain. That range serial number should come with a split drain for the manifold--a plastic fitting with two quick-connect nipples. One goes to the drain hose, which attached at the other end at the drain hose holder just to the port side of the forward end of the manifold. The other nipple attaches to a hose that splits off from the main water intake hose coming off the impeller in the lower unit. This hose provides cold raw water to the back end of the manifold for the riser water at all times regardless of engine temp or manifold flow.

Part # 22-862605T 1

 

[Grady in Texas]

Fresh (brackish) water cooled. Thanks for the part number. But I don't think it's my problem. I think I may be dealing with parts 4, 6 & 9 (maybe). More exploring tomorrow. And do I really need this line from the cooling input to the manifold or is it just a drain?

 

[TurtleTamer]

I'm sure someone removed all the EZ Drain stuff and installed that fitting in the manifold. I'd just follow Bondo's advice and repace it with another brass fitting. You don't need the drain but you do need to have that plumbed to the manifold so it gets ambient (not heated by the engine) water to the riser. It'll mix in with the regular manifold water flow right there and cool it. With the boat running you can feel the difference with your hand between other areas of the manifold and that spot.

 

[Bondo]

Ayuh,..... Take #9 outa the block, 'n put in a 1/4" pipe brass plug,....

Remove #10 from the manifold, 'n install another brass pipe plug there, probably also 1/4" pipe,....

At the hose connection, #6, you'll need a plug, or cap to stop the port in the big hose,....

If ya find any remnants of all the junk in-between those 3 fittin's,......
Toss 'em overboard,.... it's Junk,.....

 

[Grady in Texas]

Thanks for the help. The other end (also a snap-on fitting) was OK and the fitting didn't allow for replacement with a barb so I just replaced the manifold end. Water contained. The rest of the quick disconnect/drain system is still in place and I may get rid of it later.