Lower End - What Weight Oil

[Ed Haugh]

I do not have the factory manual for my 1999 150XR6. What is capacity of the lower unit and recommended oil weight?



Finally, does the motor have to be completely vertical to change the oil? I just winterized the motor, pulled the batteries, etc. The motor is tilted up on a transom saver right now. I need to put a battery back in, to change the lower unit oil, don't I? :huh:

 

[Bob G.]

I use Mercury gear oil, it takes less than a quart. Get the quart bottle, a pump and new washers. You'll want a battery in so you can raise and lower the motor. Vertical would be best for draining and filling.

 

[Bruce Freeman]

Should be vertical. For drain and refill so you get it filled propery and if it's outside it should be left that way so that it does not collect rain or snow. I think it calls for 75w90 Hypoid gl5?

 

[Berry Lindley]

There are a couple of types of this, it will list on the bottle what to use it in. Be careful to NOT to mix types of gear oil.

 

[mike daniels]

I drained my 2000 merc 90 lower unit. You probably have the same one.



I got the mercury oil and Attwood oil pump from Walmart for a good price and did it myself.



I did get the motor as verticle as I could by lower the tongue of the trailer as low as possible then trimming down. I barely fit my oil pan below the motor.



Take out the bottom plug first, then the top and you get a lot less mess. Inspect the oil for water (milky look). Let the oil drain for about 30 minutes to an hour. I did a vacuum check with a mighty vac pump from Autozone that I use to bleed my brakes in the car. They had a succion cup end that works fine the the lower unit ports. Make sure it holds vacuum for at least 1 hour and that will tell you if you have a seal leak. Whtever you do don't put too much positive pressure in the lower unit (Over like 6psi) or you can blow out the seals.



attach the pump with both both ports removed and fill until it comes out the top port. Then leave it that way for a while (I did 1 hour) to allow bubbles to migrate to the top then pump the last little bit in until it comes out the top again the put the top screw in. unscrew the pump and quickly put the bottom plug in....



Tadaaaa!!!!

 

[Bob Bourget2]

+1, Bob G, Bruce and Berry. Mike, it is not the same gearcase, although draining and filling is ALMOST identical. Merc gearcases are designed to handle 15psi to check for any leaks with any seals, o-rings, bushings, etc. Merc hi-perf oil, premium blend, AMSOIL, are my favorites, and all I use.