50 Hp Merc, What year? Also Changing lower unit oil?

[BigFish7]

I just bought a 50 hp merc 500 series, only #'s are 3170606 (serial #) can anyone help me find out what year the motor is? My motor has two screws. One silver (vent) and black plastic plug (flush) Is the flush where you fill it? But the flush is above the vent plug?

 

[Barnacle_Bill]

Re: 50 Hp Merc, What year? Also Changing lower unit oil?

1971

 

[BigFish7]

Re: 50 Hp Merc, What year? Also Changing lower unit oil?

Bill, how can you tell its a 1971? do you know anythingabout my oil question? Thanks Ray

 

[jajeeper]

Re: 50 Hp Merc, What year? Also Changing lower unit oil?

There are several web sites that have charts showing what year your motor is by the size and serial number. Check out the first forum listed called Engine FAQs to find out more about that.<br /><br />Concerning your lower unit oil. There are two plug screws. One near the bottom on the lower unit and one near the top of the lower unit. Both are on the left side of your outboard if you are facing it from behind your boat. The bottom is the drain/fill plug and the top is the vent plug. Remove both plugs to drain. Refill from the bottom until oil oozes out the top/vent hole. I find the turning the prop once the oil reaches the top usually allows the oil to settle down so i can add a little more. Put the top plug back in first while still holding your new oil container in the lower hole. Then remove the container and quickly put the lower plug in. Check it again after first use to ensure it is full. Most stores have a neat little kit that comes with a quart of lower unit oil, pump, and tubing that will screw right into the fill plug for easy filling.

 

[BigFish7]

Re: 50 Hp Merc, What year? Also Changing lower unit oil?

THANKS FOR THE INFO, FOUND A WEB SITE THAT LISTED THE SERIAL #'S. FOR THE OIL CHANGE, EVERYTHING YOU ARE SAYING IS CORRECT, EXCEPT THE BOTTOM PLUG IS THE (VENT)IT IS LABELED, AND THE TOP SAYS FLUSH. THANK YOU FOR ANY MORE INFO.

 

[jajeeper]

Re: 50 Hp Merc, What year? Also Changing lower unit oil?

Regardless of what the label on that plug is, the correct procedure is to fill from the bottom.

 

[BigFish7]

Re: 50 Hp Merc, What year? Also Changing lower unit oil?

SHOULD HAVE MENTIONED THIS BEFORE, TRIED TO FILL FROM THE BOTTON, (VERY HARD TO SQUEEZE QUART OF OIL) DIDNT REALLY WANT TO GO IN? ANY MORE SUGGESTIONS? I HAVENT DONE THIS BEFORE,IS THAT NORMAL? THANK YOU VERY MUCH

 

[jajeeper]

Re: 50 Hp Merc, What year? Also Changing lower unit oil?

Buy a pump that fits the oil container or go buy the kit I mentioned that has the oil and pump already for $10. It is nearly impossible by just squeezing the bottle, but needs to be filled form the bottom to avoid air pockets which will make you think it is full long before it really is.

 

[BigFish7]

Re: 50 Hp Merc, What year? Also Changing lower unit oil?

Thanks JaJeeper, Like I said I have never changed lower unit oil before, and I was not seeing the bottom screw. I was taking out the vent and Flush screw. Do you know what the flush screw is for? I put oil in there by accident and seemed to drain through the prop. The oil is draining now and I should have no problem filling it up afterwards. I did go out and bought the fill tube with the pump, (alot easier)

 

[andrewkafp]

Re: 50 Hp Merc, What year? Also Changing lower unit oil?

http://www.brokeboats.com/lulube3.html <br /><br />Remove top and bottom screw (and plastic shim) Drain oil out overnight. Fill bottle to the top and start squeezing (Don't let air back in bottle) If it goes dead flat, put finger over hole and add more oil to bottle.. squeeze til oil comes out of bottle and put it back in bottom fill hole. Keep squeezing til it runs freely out of top hole and air bubbles vanish . It's a very easy job and you don't need a pump.. I've done it a few times this year by using a 750ml squeeze bottle.