Merc 40 hp Lower Unit, only one opening?

[aviansam]

Forgive my ignorance, I have Merc 40HP Outboard,purchased in 1991 but not sure what year.<br />I can only find one screw labeled "vent" for the lower unit. Should there not be another screw opening higher on the unit. If not how do I fill from the bottom? I shamefully admit this is the first time since 91 that I hove opened this thing and it is dry as a bone!!! And smells like metal on metal, no duh!!!???<br />Thanks for your help!<br />Sam aviansam@aol.com

 

[jim phillips]

Re: Merc 40 hp Lower Unit, only one opening?

Look lower on the foot the one marked vent is the top plug. Go to wal-mart ,k-mart .boat yard and get a pump to fill the l/u with

 

[aviansam]

Re: Merc 40 hp Lower Unit, only one opening?

Thanks Jim I am sittin down and shuttin up!

 

[jim phillips]

Re: Merc 40 hp Lower Unit, only one opening?

This is what the board is for. I had the same question when i started that is how i could answer yours. welcome to the site and please feel free to jump in any time. If you do a search for chats you will find a link to a chat room that sbn set up on yahoo alot of us meet in there and you are welcome to join us.

 

[TELMANMN]

Re: Merc 40 hp Lower Unit, only one opening?

Once you ask a question, realize you can do it, start getting info, manuals, etc you are now heads and shoulder's above alot of people who claim they 'can't do it'. This is a great board.

 

[Bradster941]

Re: Merc 40 hp Lower Unit, only one opening?

Sam, the question should be, where did the fluid go.<br />If it were mine, I would take it to a shop and have them pressure and vacuum test it.<br />You probably have a bad seal that needs to be replaced before you run it again. <br />Also, let me guess, you haven't had the water pump replaced have you? ( a yearly requirment )<br /><br />Have your mechanic do the test 1st. Then have him tear it down. Chances are good that the gears are scorced and need replacing.<br />Sorry for the bad news, but it is better to find this out on land than on the water!.. <br /> Brad

 

[aviansam]

Re: Merc 40 hp Lower Unit, only one opening?

Thanks for all the help guys, got that baby drained,filled and gonna put her on the water today and see what happens, gotta save a few bucks before I can do that water pump thing though!<br />Mercury is an amazing product, 12 years of abuse and zero maintenance and she has only quit one time, it was some computer board chip thing, when I loaned it to a buddy to fish a tournament.<br /><br />This board is GREAT and you guys are the best!

 

[jim phillips]

Re: Merc 40 hp Lower Unit, only one opening?

If you have not replaced the impeller DO NOT RUN IT untill you do it could cost you your motor I can not express this enuff.

 

[aviansam]

Re: Merc 40 hp Lower Unit, only one opening?

Okay Lucky Jim, nest dumb question, what is the impeller, I am a veterinarian and should not work on things without heartbeats!!!<br />Sam

 

[roscoe]

Re: Merc 40 hp Lower Unit, only one opening?

The impeller is a rubber paddlewheel, inside the waterpump, that cools your engine. Kind of the heart that allows your engine to continue beating.<br /><br />They get old, brittle, dried out, and break. Then your engine overheats and blows up. You have to remove the lower unit to access it. You will need a repair manual, or hire the job out.<br /><br />Many of us replace the impeller annually, or bi-annually. The part is about $12.

 

[aviansam]

Re: Merc 40 hp Lower Unit, only one opening?

Thanks Roscoe:<br />GUy at the boatshop had some aftermarket manuals, I guess they are accurate and consistent, probably would help if I could tell you their title or who they were made by, was gonna pick one up Staurday but the did not have the one that included the year of my motor, Any comments on these, that is if you can tell what the flip I am talking about..........

 

[aviansam]

Re: Merc 40 hp Lower Unit, only one opening?

Just wonderin would the water pump still be suirtin out water if the impeller were dysfunctional?

 

[Fouled Plug]

Re: Merc 40 hp Lower Unit, only one opening?

Water pump can be working fine one minute, and fail without warning the next. Very few outboards wear out...usually fuel or cooling issues that kill 'em. It's false economy to continue to run it as-is. Replace the impeller for a few bux now, or possibly fry the motor later. An ounce of prevention.....