Lower Unit Oil change Question

[Daddydonjuan]

I want to change the lower unit oil -- I bought the oil and the pump kit.

I am having trouble finding the lower plug. I found upper oil vent screw but for life of me can't find the botton plug.

Is there somewhere to look - I have ordered the seloc book for this engine but it is not in yet. -- I figure this can;t be that hard to do please help~

Here is my info:
1998 Mercruiser 4.3 liter V6
Alpha one out drive

Oil vent on top is on left side of outdrive if your looking standing at the back of the boat.

 

[Fishermark]

Re: Lower Unit Oil change Question

The lower drain is on the same side - port side. Near the front of the nose. (At the bottom. )

 

[Fishermark]

Re: Lower Unit Oil change Question

 

[Daddydonjuan]

Re: Lower Unit Oil change Question

perfect -- Great Picture -- thanks for the help

 

[Muqwump]

Re: Lower Unit Oil change Question

Remember that this is also your fill plug! Not just your drain. I would run it for a little bit first the drain it. It makes that thick oil drain faster.

 

[imported_erick]

Re: Lower Unit Oil change Question

Any chance you can point out the upper screw? Also, what is the method? Open both then after it drains pump it in until it starts to come out the top?

Thanks

 

[OhWellcraft]

Re: Lower Unit Oil change Question

The upper screw isn't in the picture but it is straight up from the lower plug, same side and about 2-3 inches down from the very top of the drive, mine even says "oil vent" cast into the drive. Method = remove lower drain plug with drain pan under skeg and outdrive tilted down all the way, loosen cap on drive oil indicator bottle in engine compartment. Let indicator bottle drain out all the way then remove upper vent plug to drain outdrive section. Sometimes if you remove upper vent plug too soon all of the oil in the indicator bottle will drain out of it and make a big mess so keep an eye on it. Let it drain for awhile with all of the plugs out and cap off of bottle. once all drained out hook up pump to LOWER plug hole and begin pumping. 1 quart won't fill the drive so you will need two pump all of the first quart in change pump to next bottle continue pumping until oil starts to run out of the UPPER vent plug, stop and screw plug(with NEW washer) in good and tight. Then have someone in the boat keeping an eye on the "fill to this line" line as you continue to pump stop about 1/4" from line as it will usually come up a bit on its own once you are to the line screw cap back on indicator bottle. Now comes the tricky part have the lower drain plug with NEW washer sitting right close by or in your hand, with other hand unscre pump hose end and quickly replace with lower plug screw in good and tight. Check indicator bottle and top off if neccessary. keep the balance of the second quart in the boat and check bottle once in a while keep up to line. If when you drain the old stuff water comes out even a little bit or the lube is milky looking, you have water getting in somewhere and need to find out where very soon. Good luck once you do it the first time its pretty cake after that. Just keep in mind that you can't fill it from anywhere but the bottom plug, other than to add a bit once it's already filled.

 

[bamadave]

Re: Lower Unit Oil change Question

One thing that hasn't been mentioned, you need a impact driver to loosen and tighten the plugs, but easy does it.

 

[OhWellcraft]

Re: Lower Unit Oil change Question

I agree with the impact if they are super tight its the only way to get them off. But unlesss you have some experience with them I wouldnt tighten them in with one. Make sure you have a good large tipped screwdriver that has a square shank on it, tighten as tight as you can with your hands then put a cresent on the shank and give it a BIT of a SNUG then stop. If you strip the threads in the housing you are screwed. The plugs are alot harder metal than the housing so don't go nuts, but you do want them tight. Water intrusion through the drain/vent plugs is quite common and should be the first thing checked if you have water in your drive.