1983 Mercury 7.5hp "Pee Hole" Question.

[waytooruff]

Hi all. I think I have a very simple Noob question for a lot of you knowledgeable boaties.
I have owned the above motor since new and have always noticed the small stream of water that comes out the outlet in all operating conditions.
Last week whilst fishing, the stream stopped, I turned off the motor and pulled the hose off the fitting to check for a blockage. Hose was clear, but the tiny outlet hole was blocked.
While I had the hose off, I started the motor again to find a great flow of water from the hose. So all good with the impeller and waterpump.
Is there any issue with running the motor with water just coming out of the hose, or must it go through the tiny pee hole opening . Can I just drill a bigger hole to improve the flow or does there have to be some back pressure by going through the smaller opening.
Thanks heaps.

Kev.

 

[Texasmark]

I wouldn't have a problem with it as this is dump water from the powerhead and when it gets in that line it's done it's job and is headed out of the engine; don't have to worry about any back pressure at the source or any of that. If it didn't go out there it would go out at the bottom of the block into the mid section then out the prop.

If you are really worried about it, take a drill bit and clean it out with a drill motor. One thing that will do is give you a place to secure your hose and keep it from flopping around unless you push out the connector and run the hose through that hole and it's tight enough to hold it in place.

 

[waytooruff]

Thank you Texasmark for the quick response.
Hole is now drilled and hose reconnected. No dramas seeing the water stream now. I have got a very impressive stream

 

[tpenfield]

The pee hole on my Merc 7.5 would constantly get clogged. I finally drilled the hole out to 1/16" larger than original. Work fine now with no adverse affects. It's purpose is just to let you know water is running through the engine. I don't think it has any other bearing on the cooling efficiency.

 

[Texasmark]

Glad you got her fixed. I liked the assurance of seeing the stream myself BUTTTTT all it does is to tell you that the water pump is pumping. If it's plumbed off the exhaust manifold like my last 90 hp, you have no idea as to what's happening withing the engine cooling water jackets. The exhaust manifold has to be free flow since hot exhaust is there as long as the engine is running. On my 90 I had a thermostat and a high rpm pressure relief valve and even though I had a reliable tell tale, when my thermostat stuck shut I didn't know it until my over temp alarm sounded. Not sure where your's is plumbed and not sure if you have a stat that might stick shut or not.

 

[waytooruff]

Thanks Texasmark and tpenfield for your input.
I have been away for the past week but hope to get out onto the lake this week to give it a good run. I'm sure it will be just great with the bigger hole .