4hp Mercury cooling system??

Tronald

Seaman
Joined
Nov 9, 2009
Messages
58
Hi everybody, I'm new here and I have a question. I just bought an old Mercury 4hp 2 cylinder (internal fuel tank) outboard at a garage sale and I went about changing the impeller. My question is: WHERE is the water outlet (pee-hole). I can not find it anywhere. I do not want to fire this thing up and not know whether or not the cooling system is working.

Any help is appreciated,

Regards,

Joe
 

Tronald

Seaman
Joined
Nov 9, 2009
Messages
58
Re: 4hp Mercury cooling system??

Anyone?? I was thinking that maybe it sends the water down through the exhaust port??
 

dan2sv650

Recruit
Joined
May 24, 2012
Messages
3
Re: 4hp Mercury cooling system??

i have a 1969 4hp merc 40

cannot find tattle tail/pee hole?

bought service manual and no luck. replaced impeller with whole kit and oil in lower unit. motor hasnt run in 20+ years. fired up after the above and new spark plug, fresh mixed gas and a few extra pulls. no shut off that i could find so choked it out after i didnt see a tattle tail. im running it in a 50gal drum with plenty of water .

any help is appreciated!

-Dan
 

micromercury

Recruit
Joined
Jul 25, 2012
Messages
3
Re: 4hp Mercury cooling system??

Dan,

I'm interested in knowing the same thing for a later model 4.5 mercury outboard.
I have no idea where the "return" water goes, but the pee-hole isn't producing
squat on my motor. I ran it a very short time, pulled cover, spit on head and it
sizzled.
No more testing on my end until water circ. verified!

:eek:
 

dan2sv650

Recruit
Joined
May 24, 2012
Messages
3
Re: 4hp Mercury cooling system??

any help?

i disassembled lower unit again copper tube was seated properly in the water pump housing.

i get some exhaust out the center rear hole on the bottom cowl.... im guessing this is where the tattle tail should be?
 

micromercury

Recruit
Joined
Jul 25, 2012
Messages
3
Re: 4hp Mercury cooling system??

Found the issue. Impeller worn away. Put new one in today. We'll see what happens.

any help?

i disassembled lower unit again copper tube was seated properly in the water pump housing.

i get some exhaust out the center rear hole on the bottom cowl.... im guessing this is where the tattle tail should be?
 

Fishin Magician

Petty Officer 2nd Class
Joined
Aug 7, 2012
Messages
123
Re: 4hp Mercury cooling system??

Dan,

I'm interested in knowing the same thing for a later model 4.5 mercury outboard.
I have no idea where the "return" water goes, but the pee-hole isn't producing
squat on my motor. I ran it a very short time, pulled cover, spit on head and it
sizzled.
No more testing on my end until water circ. verified!

:eek:

hey guys..I have a couple of the 4.5 hp merc OB's....

There is 90 degree fitting at the top of the head right next to the spark plug....that fitting has a small hose on it that drops down ( 6inches ) throught the cowling and exits the engine coolant path......comes out strong and very noticable.. approx 8 inches... behind the forward reverse shift lever on cowling...no water coming out go to impeller and check friction plate...maybe melted....hope this helps...http://www.sterndrive.info/mercury-outboard-parts/id39.html check out the parts list

FM
 
Last edited:

dan2sv650

Recruit
Joined
May 24, 2012
Messages
3
Re: 4hp Mercury cooling system??

hey guys..I have a couple of the 4.5 hp merc OB's....

There is 90 degree fitting at the top of the head right next to the spark plug....that fitting has a small hose on it that drops down ( 6inches ) throught the cowling and exits the engine coolant path......comes out strong and very noticable.. approx 8 inches... behind the forward reverse shift lever on cowling...no water coming out go to impeller and check friction plate...maybe melted....hope this helps...http://www.sterndrive.info/mercury-outboard-parts/id39.html check out the parts list

FM


thanks for the help....

i got a temp gun, my marine mechanic said as long as i dont get over 150deg F on the head it is ok.

ran it and never got over 130 deg, ran for about a minute and the pee hole started producing a stream of water.

when looking at the rear of the motor, it was on the left side tucked up under the corner of the bottom cowl, bout an 1/8in hole.

motor runs great, but im already thinking in need a 10hp to get where i want to go! pretty slow going in a 12' boat with gear.
 

Fishin Magician

Petty Officer 2nd Class
Joined
Aug 7, 2012
Messages
123
Re: 4hp Mercury cooling system??

glad your pumping water now!..however mine squirts almost immediately..upon starting...maybe you just had a little booger in there..hehe..anyway
yeah it's a slow go with a 4.5 hp ...that's why they call it a "pusher" or a "kicker".....my buddy has a 7.5 hp on a 12 foot fiberglass and runs circles around me......
I'm in no hurry....
FM
 
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