change gear oil mercruiser alpha one

roffey

roffey

Junior Member
I will be changing the gear oil in my out drive this weekend. There looks to be some sort of reservoir? From what I read on the net I think I have to remove both the fill screw and the vent screw, let the oil leak out. Put the bottom screw back in. I fill the reservoir until it leaks out the vent then replace that screw and keep filling the reservoir to the full mark?​
 
Sounds like you are talking about trim fluid rather than gear oil,correct?
The gear oil for the outdrive would be in the lower unit itself.The trim fluid resevoir would be mounted inside the transom. The trim fluid if i recall is 5-30w oil (you had better check on that) and then gear oil for lower unit.
 
Liam said:
Sounds like you are talking about trim fluid rather than gear oil,correct?
The gear oil for the outdrive would be in the lower unit itself.The trim fluid resevoir would be mounted inside the transom. The trim fluid if i recall is 5-30w oil (you had better check on that) and then gear oil for lower unit.
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No, I did mean gear oil in the outdrive. There is a what looks to be a reservoir for gear oil. I found this

http://www.mercstuff.com/reservoir.htm

it looks to be close to what I have. Just not sure how to fill it, from the top or bottom.
 
take both screw plugs out, remove the top of the resevoir. Fill from the bottom plug, you'll have to get a pump when you pick up the gear lube, don't worry, its cheap. You fill from the lower drain hole till it comes out of the upper vent hole, then put that vent screw back in and fill till you have the level in the reservoir. If it doesn't want to fill the reservoir after you got it to the vent, you can just top off the reservoir, you will need to add some more after you run it. Biggest thing is to fill the drive from the lower drain hole, that keeps it from trapping air in the drive. You only have to be 6 or 7 ounces down to wipe out teh upper unit, that's why they added the resevoir
 
so is that kit an add on? or was it standard equip on certain years ?
I have a pre alpha, "R" drive i believe, and it does not have the resevoir.
Is it worth adding,it screws into the upper vent i presume or is there an additional hole drilled in the gearcase?
sorry for misleading you
TIA
 
This is my first season with the boat. I found the reservoir when I started to take boards apart when try to troubleshoot a trim problem (yahoo, a $80 switch will fix that problem). Thanks spareparts, I thought filling from the vent is a no no. You told me what I thought was the way to go. Correct me if I am wrong but the reservoir is an add on and is there to insure oil is always on supply.
 
the reservoir was an add on on the alpha gen 1 set ups, its standard on gen II and bravo drives. You can add it to any drive. It used to be available, I haven't looked lately to see if it still is. I used to build a bunch of out drives, till the reservoirs came out(especially with the alarm), it really cut down on how many out drive failures there was
 
spareparts said:
the reservoir was an add on on the alpha gen 1 set ups, its standard on gen II and bravo drives. You can add it to any drive. It used to be available, I haven't looked lately to see if it still is. I used to build a bunch of out drives, till the reservoirs came out(especially with the alarm), it really cut down on how many out drive failures there was
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Not all BRAVO's had it. I had an 89 BRAVO that did not have the factory reservoir plumbing in the outdrive. I want to say it was 91 they all came with it. And like spare said ONLY fill from the lower drain plug. Your going to need about 3-4 quarts to refill it.
 
Its funny you mentioned you're doing that. I pulled my Alpha lower unit yesterday and replaced the water pump impeller and refilled the unit with new oil. Pumped it in from the bottom hole, held alittle more than a quart. Good luck with yours!
 
My fix for the trim tabs will not be as smoth as I thought. My parts people called me back to report the part is no longer available... I am going to see if I can pick up a used one, my switch has 4 buttons on it... I guess the new ones are a rocker switch.
 
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