Can't Identify mystery hose

[scb1712]

Hi,

I've got a Volvo Penta GS-PEFS 3.0l engine. There is a small water hose (maybe 1/4 in. I.D.) that comes off of a brass fitting on the manifold right near the carb. On my boat the hose just hangs into the bilge and has a bolt stuck into the other end. I know its a water hose as water came out of the fitting when i was flushing out the manifold from the water intake recently. Looking at the schematics online at marinepartsexpress.com, i don't even see this fitting or hose listed with the replacement manifold.

Can anyone tell me what it's for or where it should run to? Could it be used as a tell-tail to determine if i'm getting water throught the exhaust?

Thanks,

Steve

 

[isleno1]

Re: Can't Identify mystery hose

Is it on the bottom of the manifold?

 

[scb1712]

Re: Can't Identify mystery hose

No - the fitting i'm referring to comes out of the top of the manifold. It's a brass elbow that sits in about the centre point of the carb (between the two mounting "feet"). It is on the starboard side of the manifold between the carb and the valve cover.

 

[Don S]

Re: Can't Identify mystery hose

Can you post a picture of it?

 

[Maclin]

Re: Can't Identify mystery hose

I have posted a link to a drawing below. The part identified as #3 just says "Plug" for a description. It seems to be where you describe the fitting that your mystery hose is connected to. It may be a previous location for a temp sensor or something. Maybe it is a poor man's hot water tap now?

Your pics would be invaluable though as far as helping figure out what a previous owner rigged this for.


http://dougrussell.com/partscatalog/volvo_omc/index.cfm?fuseaction=comp&group=3160&GroupList=3179,3178,3153,3156,3157,3162,3152,3151,3150,3177,3158,3169,3168,3161,3159,3170,3172,3160,3155,3154,3167,3165,3166,3163,3164,3175,3182,3173,3174,3176,3181,3180,3171

 

[Don S]

Re: Can't Identify mystery hose

The PEFS model didn't have the fitting in the exhaust tube, and I didn't find anything in the manual except the fitting in the elbow. Nothing showing where it hooked.
Here is the part diagram for the EF model.

 

[scb1712]

Re: Can't Identify mystery hose

Okay - here is a photo of the manifold with the fitting. Unfortunately it isn't on the engine right now, but the hose just hung down and into the bilge off of this fitting, with a bolt in the opposite end. While i'm at it - i noticed that in the diagram, there is a plate between the manifold and the riser which seems to restrict water to only one of the passages. What's the purpose of this restrictor plate as my boat didn't have one when it came apart?

 

[wellcraft19]

Re: Can't Identify mystery hose

This might be a wild one, but could it have been that the previous owner in some way used the hose as sort of a "bleed" hose to ensure that he actually had circulation in the raw water system? We all know that a "well maintained" engine does not need it, but I sort of like the trickle (a small stream) of water coming out of outboards and older diesel engines - just for the purpose to at least tell you that you have some water flow...(not necessarily adequate).

Or, as a way to easier flush out the exhaust manifold of sea/salt water (but probably not much of the salty stuff in and around Ontario). Looking at the pictures, the exhaust ports looks a tad rusty on a few cylinders.

 

[scb1712]

Re: Can't Identify mystery hose

It was originally a Florida boat, so using it as a flush hose wouldn't be that wild a guess. However, given the state of the riser, manifold and bellows, i don't think maintenance was a top of mind concern. We've got good compression in all the cylinders and the oil isn't at all milky which are good signs. I also wish that these i/o's had some kind of tell-tail water stream to know that the cooling system was working. If we had one, we likely wouldn't have overheated it on our first trip out.

As for the bleed hose - it's not a bad idea, but i'm wondering why you wouldn't just remove the bleed screw on the riser to see if you've got water flowing?

 

[mlpaskett]

Re: Can't Identify mystery hose

Maybe it was PO source for hot water for transom shower...

 

[ta79pr]

Vacuum port for tuning the carb maybe?