x-flow water pouring out of midsection

lorax

Petty Officer 2nd Class
Joined
Nov 3, 2002
Messages
134
just got my '79 OMC 140 going after reinstalling powerhead. I started it on the muffs and noticed water coming out between the mid section and the lower unit right next to the lower motor mount.<br /><br />what did I do now?<br /><br />thanks
 

ob

Admiral
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Aug 16, 2002
Messages
6,992
Re: x-flow water pouring out of midsection

I believe there are cavity drain holes behind the mounts.If you had the lower unit dropped while rebuilding ,it could be that the waterpump discharge tube is not sealed well.<br />On a lighter note,I recently installed a new waterpump on a 96' 70 Rude and noticed a bit of water coming from my cavity drains which I hadn't noticed before.The updated pump kit for mine uses a 6 flute impeller instead of the original three and moves more water than before.If engine cools fine and the leakoff is not excessive you should have no worries.
 

lorax

Petty Officer 2nd Class
Joined
Nov 3, 2002
Messages
134
Re: x-flow water pouring out of midsection

thanks for the response.<br />I didn't drop the lower unit or remove the adapter plate. I did, however, replace the thermostats and pressure reliefs.<br />The water coming out is substantial. I'm thinking I better pull the powerhead. :(
 

ob

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6,992
Re: x-flow water pouring out of midsection

If you are running this engine on hose ,You are not using full pressure,right.Probably a rhetorical question as I'm sure you've flushed many times before.
 

lorax

Petty Officer 2nd Class
Joined
Nov 3, 2002
Messages
134
Re: x-flow water pouring out of midsection

I don't think I had the hose cranked open anymore than usual. <br />I'm wondering if I could have screwed up the relief valve installation when I replaced the thermostats. The book says that the relief valves don't open till higher engine RPMs but I'm wondering if they are stuck shut and with the thermostats closed (cold engine) would that cause excessive presure that might leak through(and out) the mid? :confused:
 

ob

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Re: x-flow water pouring out of midsection

Lorax,To be honest with you it is difficult for me to judge what you are describing as a substantial amount of water leaking from behind the mounts from the cavity drains to give a recommendation as to tear down or not. A moderate dribble is acceptable.A heavy stream or gushing would suggest a leaking discharge tube or restrictive back-up in water circuit.What you don't want is more water entering this cavity than can be drained out while running or you run a risk of water backing up the exhaust leg which can reach the powerhead causing substantial engine damage.For this reason ,it is suggested to not use full city water pressure when running on hose,which I think you have established is not the case.<br /><br />If you feel there is a chance that the relief valves were not installed properly ,I would definately remove the cover for a second look.While cover is off ,you can backflush some water down through the housing and down the lower unit ,out the intakes to see if there is an obstruction.If the old relief valves were missing or stuck open ,this may explain the presence of water not seen before exiting the drain ports behind mounts with new seating ones installed.
 

lorax

Petty Officer 2nd Class
Joined
Nov 3, 2002
Messages
134
Re: x-flow water pouring out of midsection

That's helpful OB. Thanks.<br />I've taken the powerhead off. There isn't anything obviously wrong at the powerhead/adapter plate union. I guess my next move is removing the thermostat housing like you suggest.<br />I don't know how to describe the quantity of water except to say I never noticed any water coming from that area before and now it's flowing out at a good rate. Not a drip or trickle but flowing.
 
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