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Mariner 8hp water circulation

"hi,
i installed a new water


"hi,
i installed a new water pump kit, thermostat and cleanned the system as much as possible.
water circulates but I am not sure if the circulation is strong enough. the circulation is lower at idle but it doesn't seem to change from throttle opened 1/3 or full throttle.
is this ok? how can i check if i have water circulation problems?

thanks"
 
"German, as long as you have a

"German, as long as you have a decent tell-tale stream, it doesn't feel warm to the touch and the motor itself doesn't get so hot that you can't keep a finger on the waterjacket, the cooling is probably fine.

The water pressure is pretty low on these little motors - about 1 - 2 psi (max at idle) and 5 - 7 at wide open throttle..."
 
"hi graham,
actually the wate


"hi graham,
actually the water coming out from the tell-tale is very warm, maybe even hot. is there anyway to know if the motor is over heating?
thank you
german"
 
"anything over 140 is to hot,

"anything over 140 is to hot, lay your hand on the top of the engine, if you cant hold on then there is something wrong"
 
"German, you haven't liste

"German, you haven't listed a model or serial for your motor. I mention this because, the little Mecury built Mariners (and little mercs themself) have a common issue with the waterpump covers.

It's not exactly a problem, just that upon changining an impeller, alot of guys either get the seal wrong or alternately fail to notice that the seal is in fact bad.

So if you have a Merc-Mariner as opposed to a Yamaha-Mariner, I can give you something to check....."
 
"hi,
it is the japanese marin


"hi,
it is the japanese mariner
s/n: mariner8 677 S 030085
which part of the engine should I touch to see if it is indeed overheating? next to the plugs are?
thanks again
german"
 
"German, yes, anywhere that yo

"German, yes, anywhere that you can safely put your hand - down near the plugs is fine. It should be warm to very warm, but you should be able to easily keep your hand on it.

If you can't and you suspect then that the water is not pumping correctly or at suffient pressure, I would first pull the lower unit again and inspect the pump seals - 90% of the time that is where your problem will lie.

Usually, when a motor is pumping "some" water it can often be traced to either a bad seal or broken/missing gasket at the waterpump end of things. Or alternately, sometimes, upon install, the impeller will slip the little key that drives it. Friction will allow it to pump a little, but at higher rpm it simply slips...

I will post a diagram. #36 in the picture (the rubber seal where the water-tube enters the waterpump cover) is a common point of failure. Additionally, ensure that the waterpump is tightened down suffiently.

114569.jpg
"
 
"hi graham,
I checked the mot


"hi graham,
I checked the motor again.
I can hold my hand on the cover of the thermostat, but if I put it next to the plugs, it will be ok when idling by if I open the thottle half way, in gear, it will burn my hand after a few seconds.
I removed the water pump again. The key is in place and the impeller is rotating well. the water tube sits fine in the rubber seal (#36), but I suspect that might be a hole or a leak somewhere in the water tube. is this possible?
When the water circulates, appart from the tell tale, a little bit of water comes out from the rubber plug which hides the shift rod connector, and also from a hole above the vent slit, just above the cavitation plate.
how difficult is to change the water tube?
Is there anyway to test if indeed the tube is the problem?

thanks again
german"
 
"German, from what you describ

"German, from what you describe, you are not getting enough water up to the head.

Yes, I have personally changed a couple of water tubes that were burnt/rotted right through. In both cases the motors had been run in salt water.

It is not an overly difficult job, but may require the removal of the powerhead (as a whole unit). This would look to be the case with your motor as well because of the apparent way the water-tube is fastened at the top of the exhaust housing.

If you are going to attempt this yourself, ensure that you get a manual.

I don't know of an easy way to assess the water-tube other than taking it off and looking at it...."
 
"hi graham,
i have the seloc


"hi graham,
i have the seloc manual, but it doesn't talk about the water tube at all.
I noticed that the water tube has two parts: one short section of a cupper (i think) tube that connects to the water pump and on the other side to a longer and wider tube that goes in the the power head. do you think the problem could be the short tube? is that possible to remove the short tube without removing the whole engine from the shaft?
I have only repair water pumps and carbs. Can I damage the engine by removing the powerhead, if I have no experience doing it? is there something in particular I should be very careful about ?

thank you

german"
 
"german, hook a waterhose/faus

"german, hook a waterhose/fauset on the tube, turn it on slightly and look for a leak in the tube or up by the powerhead. you can also use low pressure air"
 
"hi jb,
I tried the water hos


"hi jb,
I tried the water hose, but it is hard to say, because I have no perfect adaptor to connect the hose to the water tube so some water is leaking at the connection and there is no much room to look inside.
how do i know if there is a leak by the powerhead?
should i remove the thermostat and see if water is coming out from there?
when i bought the motor, the thermostat housing was very dirty, is it possible that it's still dirty inside the powerhead? is there anyway to clean it without opening?
using a salt off solution might help cleanning it?
i also noticed that the first part of the water tube (the cupper one) is not totally round at the bottom end. can this cupper section of the water tube be removed and replaced or should I replace the whole tube up to the power head as one piece?

thank you
german"
 
"the hose must be reduced in s

"the hose must be reduced in size to a point far enough away so you can tell whats leaking. That being said I don't think your water tube is supposed to be flat at all. Lets remove the thermostat completely and check for water flow and temperature. these engines really don't need the thermo unless used in water temps less then 50*f. I would also try the low pressure air to check for obstructions. Vinegar is a good cleaner that won't harm anything, rinse with water.
Graham might have to help with the water tube since I don't know if it can be removed without disassembly."
 
"thanks jb,
the water tube is


"thanks jb,
the water tube is not flat at the end, but it is not perfectly round, more kind of a bit oval.
I tried to use one of the compressed air cans but it is hard to tell where the air is escaping from.
how should i pure the vinegar? shall I fill the t-stat housing with vinegar and let it sit for a while?

thanks
german"
 
"if you don't plug the low

"if you don't plug the lower water tube the vinegar will run right out, maybe even find your leak if you have one. I have never had one so bad as to have to use some sort of cleaner, you are on your own. But I would remove the t-stat and poppet valve if equipped. A shop vacuum would work for low pressure air if you want to go that route. I would put the lower back on and run without the t-stat to see what happens."
 
"Don't want to jack your t

"Don't want to jack your thread but --- I just replaced the water pump on my 1988 merc 9.9 and can not get the pump outlet to line up-connect with the motor inlet pipe. I lose sight of this connection as foot closes, got any ideas?

thanks,
Richard"
 
"I don't think so, when I

"I don't think so, when I removed the old pump the #36, rubber part that connects pump to engine was stuck to engine side copper pipe and took a LOT of pull-twist to remove."
 
"richard,
you can't see w


"richard,
you can't see while pushing the lower unit into the shaft. I used my finger to feel it. put your finger so you can touch both groumet and cupper pipe in such a way you can align them while pushing the lower unit in. is sometimes easier to do it when the motor is on the floor laying horizontally instead of being hanging vertically.
another tip is to lubricate both the gourmet (#36) and the cupper pipe so it will slide in easier.
how long is the cupper tube in your case? how is it connected to the water tube (also with a rubber gourmet?

german"
 
"JB,
7.pdf didn't display


"JB,
7.pdf didn't display anything?

german,
not at home now but feel there is not room for a finger on mine, water pump is in the way, but I'll sure try.The copper pipe is just long enough to touch pump 1/2" before foot closes.
Richard"
 
"<center><table border=1><tr><

"<center><table border=1><tr><td>http://www.marineengine.com/discus/icons/mime_pdf.gif""" align=left alt=""application/pdf"">
[url=""][b]19708.pdf[/b][/url] (49.0 k)</td></tr></table></center> this might be better"
 
"Richard, I own 3 of these mot

"Richard, I own 3 of these motors and have changed countless impellers on others. Parts 29 and 32 on JB's pic often times remain attached to the water-tube when you take off the lower unit.

Number 29 pulls right out of the waterpump cover and must be seated (pressed back in) properly or it will cause all end of problems for you.

And yes, you don't have alot of space to play with to get the water tube back in the guide tube (#32) but should be able to barely get a finger in between the lower unit and the leg to get them lined up and then just hope they stay lined up as you bolt it all back together


With the water tube roughly lined up and just touching the guide tube, I usually move the prop by hand to get the drive shaft to mesh up at the top end (with the gears in reverse) and slip in, then the water-tube has nowhere else to go except into the the pickup tube on the cover..."
 
"Didn't see this post yet,

"Didn't see this post yet, hope its not delayed and you get it twice. Does part #32 come off the water tube? That will really help. What is #95 2-4-c ?
Richard"
 
"Richard, yes, 32 comes off th

"Richard, yes, 32 comes off the water tube. You put it back on the stub of 29, and then guide the whole thing back into the water-tube upon reassmebly (if it is remaining on the water tube that is probably why you noted "no finger room").

It's job is act as a guide tube during reassembly.

And yes 2-4-C is just a teflon lubricant

JB, you are worrying me now - trying to move in on my picture action - but mine are still prettier
biggrin.gif
"
 
"hi graham,
i just remembered


"hi graham,
i just remembered that once i change a water pump in a johnson 6hp outboard. between the cupper tube and the main water tube (the one attached to the shaft and goes all the way to the powerhead) was another gourmet (like #36) which was broken and obstracting the water flow.
is there anouthe gourmet also in the mariner or is just one piece to the powerhead? to replace this top gourmet took me a long time in the johnson. do you know the dimmensions of the cupper tube? maybe i should take it out and replace it.
thanks
german"
 
"hi graham and jb,
today I ch


"hi graham and jb,
today I checked the water tube by flowing water from the thermostat housing. the water seems to flow well going out through the end of the water tube without any notice of any leaking. the same thing happens if I connect the hose to the end of the water tube,
I will try the vinager tomorrow.
when I touch the motor, the t-stat housing doesn't get warm, but the plugs get really hot. the power head (next to the plugs), when in gear it gets hot, i can leave my hand there for about 20 secs. I can leave my hands as long as i want on any other part of the motor.
Is there any other way to more acuaretly know if the motor over heats?
on the lower unit, bellow a screw which says "wash" there is a hole, when the motor is pumping water, some flows out through that hole.
it doesn't seem that a screw is missing. what's the purpose of that hole? I tried to put my finger to see if blocking it will improve the water circulation through the power head, but it doesn't.

thanks
german"
 
"German, it sounds like it coo

"German, it sounds like it cooling about right. The plugs should get hot, there secondary purpose (after sparking) is to dissipate heat from the engine - so I expect them to be hot.

I would still go ahead with the vinegar but sounds like things are ok now..."
 
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