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Will the water pump work on a mercury outboard motor 7.5 if the lower unit oil is low

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First things first, never let your lower unit lube be low. It should be changed every 100 hours of use, or at least checked after big trips with prolonged use. If it is low, but does not look grey, milky or burnt, then just add from bottom plug until it comes out of the top plug. Now, the water pump is completely separate from your oil situation. Whether or not your motor has what is called a "pee stream" does not necessarily mean you have a bad water pump. Often times the water flow indicator, or "pee stream" on your engine will be plugged, which is okay, it\'s just an indicator. However, if you were to test run your engine on a garden hose at home, and there was no flow out of the propeller hub, which is actually where the exhaust flow exits as well as your cooling water, then you\'ll need a new water pump impeller and/or possibly a water pump kit. This should be around 40 to 75 dollars in parts, and about 1.5 hrs in labor if you were to take it to a shop.

Posted on May 15, 2014


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SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

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Posted on Jan 02, 2017

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SOURCE: 2008 Yahama 90 2 stroke outboard lower unit fluid leak

Ok by fluid I assume it is gear oil leaking yes?
There is every chance there is the smallest seal leak there that may only be present once the gear case gets a little pressure in it, either through use, or through expansion as the leg heats sitting in the sun even. Have you got a new washer installed under this screw to properly seal it? Usually a nylon type washer is best.

Also, how do you know the lower unit is not leaking or have water intrusion? Have you drained the gearbox oil recently? If so what color was the oil, milky looking at oil or good semi-transparent oil color?

Posted on Mar 16, 2009

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SOURCE: Free wiring diagram for 1978 Mercury Outboard 115 HP boat motor

I have a maintainance manual for this engine (I have the same one) with pages of wiring diagrams. What specific system/area are you interested in, I could scan in the page(s) and email them to you.


Posted on Sep 20, 2009

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SOURCE: wiring diagram for 1982 Mercury 6cyl outboard tilt

go to ebay and buy a manual

Posted on Mar 27, 2010

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SOURCE: suzuki outboard motor 65 hp --oil sensor keeps

assuming you are not out of oil in your oil reservoir you probably have a bad sending unit in the reservoir. never bypass it or eliminate it as you could permanently damage your motor or ruin it if you ran it out of oil.

Posted on Jun 20, 2010

  • 1654 Answers

SOURCE: The low water pressure and

Not seeing anything particular, especially on this motor, there have been overheating on different models but nothing new like yours. Since it is new, please call the dealer who sold this to you, there is factory warranty that you need to use, if you alter anything then the warranty will be void. With that said, always make sure the stern is in the water deep enough to draw the water in, if trimmed it losses its ability to draw water like it should. The Poppet valve could be sticking or the thermostats can be bad, this is not that uncommon. Ther is also the hose that connects inside to the water jacket that may have come loose and not impossible but maybe you sucked up something that hurt the impeller for the water pump. Bad timing can cause this as well as a cylinder not getting the correct amount of oil. These thing can fall under the lemon law just like cars, if the motor had issues when you bought it, the manufacture is required to fix these issues. I wish I had a canned answer to this but there is none. It could be as simple as a bad temp gauge giving you a false reading. Does the motor actually seem like it is running hot or is the alarms just going off? 10 hours isstill a brand new engine and the dealer should have to remedy this. You need to find out if it is overheating or there is some other problem like running lean, as either one will destroy a motor if you keep running it like that.
I assume you checked the intakes for blockage, and the water coming out of the weep hole is strong and warm. You can try cleaning the weep hole with some weed trimmer string to see if something is blocking the exit.

Posted on Mar 14, 2011

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1995 mercury 115hp water pump replacement kit

May 27, 2017 | Seloc Mercury Outboard Engine Repair...


Outboard motors

Keep the gas in your outboard new/clean with new oil every 6 months..Keep your motor covered when not in use, Dirt dabbers (dobbers) will build nest under the hood and break loose and ruin your motor, ,,Change your water pump and thermostate every year when motor is used a lot.....Dont run stainless steel props on small hp motors ,when you hit a log it will bend your prop shaft costing big $$$ to replace..Ck your lower gear oil if water is noted ,replace lower seals...Dont buy used motors unless you run a compression for water in gear case , Dont buy 4 strokes to heavy to slow to many parts AND are being replaced by fuel injection 2 strokes .... Dont buy FORCE motors not made by mercury no parts being made and or extink and pure junk . Etex best motors , .

on Mar 16, 2011 | Boating


Changing oil in lower unit on an outboard motor.

the oil in the lower gear case in a outboard motor should be changed every fall when you take the boat out or once a year if you live where you can boat all year. when you look at the lower unit down by the propeller you will find two screws one lower and one upper. take the upper one out first and check the nylon gasket and replace if worn. put a coffee can or and oil collector under the moter and take out the lower plug. if possible do this after the moter has been run recently, but never run an outboard out of the water unless you have the garden house hooked up to ear muffs over the water intake sites!
the oil will slowly drain out. if the oil looks like chocolate milk it probably has water in it which means its leaking at the upper or lower seals and needs a pressure check and possibly seal replacemant. after all the oil is out (30 minutes or so) its time to refill it. for less than ten bucks you can but a simple device that lets you pump the oil in instead of squezzing it out of the tube. you attach it to the lower drain plug hole and the to a quart of the proper fluid for your motor. make sure you buy the oil to match your type of outboard.
pump the oil or squeze it it from the bottom until it starts to come out the top hole. make sure all the bubbles are out then put the upper plug back in with good gasket, remove the oil tube or appicator from the bottom hole and quickly relace the bottom plug as well with a good gasket.
thats it and you are good to go for the season. if you see oil leaking out the prop shaft or at one of the plugs you need to attend to that soon. tip remember chocolate milk oil or actual water means a seal leak and must be may just be a .25 nylon seal for one of the plugs is bad! any unusual noises of difficult or loud shifting can also means problems with the lower unit gears etc and its always cheaper to fix the problem sooner than later.
happy boating!!!!!!!!!!!!

on May 16, 2010 | Boating

1 Answer

I have a 1978 merc 85 hp outboard with a bad pump i purchased a used one that works mine has 4 hoses

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How do I winterized a 40hp evenrude 2stroke

There are videos all over YouTube that cover this subject quite nicely.
winterizing an outboard motor YouTube

Nov 15, 2014 | Boating

1 Answer

Oil pump check

Those motors have a sensor on the oil pump drive gear that senses the oil pump drive shaft spinning. That sensor could be going out giving a false code. You can take off the oil line exit on the pump and crank the motor up for no more than a minute to check for oil flow. It won't be much at all....a dribble is all you can expect on idle. The most common problem is the oil tank on the motor itself or the sensor probe in the tank. The float can fall off giving a false signal as well. Make sure the cap and hoses are tight on the remote oil tank as the motor pressurizes the tank to push oil to the motor reservoir.

Aug 19, 2017 | Mercury Outboards - Zinc Merc Outdrive

1 Answer

Oil dirps out of water pump hole setting with motor not running

Depending on the size and make of outboard you will notice oil out of the prop exhaust. This would be different on a 4 cycle engine, because the oil on a 2 cycle leaves the engine in the exhaust.

Depending how the pump pickup is made, the bottom of the motor draws water from close to the exhaust.
You can check the lube in the lower unit to see if it is milky or low on lube as it may be cracked internally. Then you can check whether your plugs are oil-fouled.

If you still need help add the type of motor(2 or 4 cycle) and brand and HP.

Mar 18, 2010 | Boating

1 Answer

Where is pee hole on 1980 Mercury 4 HP 2cyl 2 stroke

Hey I just got the same motor and actually have the same exact concerns. Have you found any answers?

Aug 30, 2009 | Boating

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Gear box oil leak

Here is a website where a manual for you outboard may be purchased.  Outboard Marine went out of buisness in 2000 and thus no parts of origial manufacture are support is available . Therir are secondary markets .    THe Lower case splits in half and their is a seal around the prop shiftm which is pressed in. The seal between the cases are cut o-rings which are placed and glued into place with gasket seal.
The water pump is located where the case splits a little bit higher. You must open the little port on the side and take out one of the screws to the connecting shift linkage to split the case. After splitting the case the drive shaft and water pickup tube(s) wil come out of the powwer head or the tubs may stick into the power head which is ok. Place the lower skag into a vice and remove the 4 or 5 screws to the water pump housing. Remove and replace impellor and impellor plate if available. If part(pieces) of the rubber impellor is missing flush out the tubes and the power head to remove them.   When reinstalling the lower unit use a flash light to make sure that the tubes return  to the proper place in the power head and the shift lever is resecured. If you need more assistance, just write back. I was an Outboard motor mechanic for five years about the time of your motor.  

Dec 23, 2008 | Boating

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