help water coming out of propeller 65hp 74 mercury 3 cyl.

[jldsomething]

i started my boat up this year with the muffs on and it wasnt peeing much water out then i noticed a stream coming out of the middle of the propeller. i also noticed it dripping from the left side of the engine where the thermostat is and spitting out of the exhaust ports. i tested compression and it was good on all three cylinders so i took it appart and noticed a striped stud on the water pumper so i used the tap and die kit and fixed it and put it all back together i think its stoped coming out of the prop i stuck it in a barrel of water this time thinking maybe the hose was just giving it to much pressure. i still have it coming out of the exhaust just like spiting. also it was running kind of bad i was guessing water was blocking exhaust port and not allowing enough air flow usually it runs like a top.

my guess is blown gasket between the exhaust and water ports on the left side where the thermostat is iv already got all new stuf on order for that but i was still worried about water coming out of the prop. its not now but is that a normal thing ? should i replace some seals in the lower unit or anything? i cant find any real info to help me out hoping someone could help me i just dont want to mess up the lower unit iv put to much in this motor anyways. thanks.

 

[Moody Blue]

Re: help water coming out of propeller 65hp 74 mercury 3 cyl.

water thru the prop exhaust is perfectly normal. Most of the cooling water is expelled out the prop with the exhaust gases. A little water is bypassed for the telltale. Water will exit the exhaust relief ports when back pressure is too high (motor running in the water but not moving).

Check your telltale output. Mine sometimes gets plugged with mud dawber wasps. A piece of grass trimmer line works well to clean out the telltale.

 

[jldsomething]

Re: help water coming out of propeller 65hp 74 mercury 3 cyl.

ok well i never seen that but the only time i guess i would is if its running on the muffs and maybe the pressure was just to high this time. the engine wasnt running well for some reason either but it could just be gas or carbs from sitting all winter. so if the exhaust is the prop what is the 6 lines in the shell below the block theres where im getting some water spitting from. my guess right now is just from a bad exhaust gasket between the exhaust and where the water runs through on my engine do you think that would cause my engine to run bad? i had it started a few days before this and it ran great no problems and the only thing that changed was where water is leaking now its prolly original gaskets on a 74 engine so its not that unexpected stuf like this will happen.

 

[merc850]

Re: help water coming out of propeller 65hp 74 mercury 3 cyl.

Water also exits out of the slots above the anti-cavitation plate and I'm not 100% but I don't think that year had a thermostat - my 1975 850 doesn't have one. Don't crank that water hose too high, just enough to create a flow.
I'd like to post a diagram but the attachment window isn't working.

 

[jldsomething]

Re: help water coming out of propeller 65hp 74 mercury 3 cyl.

mine has a thermostat i know that i ordered new gaskets and stuf online theres a bumb in the plate where the thermostat goes and its dripping water out of the hole in the middle of it and spitting out them slots its never done that before either and thats when it was in a container of water insted of the muffs. im not sure but i really think one of the gaskets is bad and is leaking water in the exhaust causing some flow problems and making it run a little bad. but like i said im no boat mechanic thats why i figured id pick some brains and ask on hear.

 

[merc850]

Re: help water coming out of propeller 65hp 74 mercury 3 cyl.

Run the engine for a min. or so then stop and check the plugs for water drops this would indicate a bad water jacket/gasket.

 

[Moody Blue]

Re: help water coming out of propeller 65hp 74 mercury 3 cyl.

im not sure but i really think one of the gaskets is bad and is leaking water in the exhaust

Water is intentionally mixed with the exhaust gasses at the exhaust plate at the base of the powerhead. The water helps to cool the exhaust gasses as they are expelled down the exhaust tube and out of the motor.