Mercury Lower Gear Oil

[cieranc]

Hi all, just got hold of a service manual for my 1973 Mercury 500 blueband. It's extremely comprehensive, tells you everything you need to know, except where the bloody engine dipstick is??? Anyway, does anyone here know what specification the Mercury's lower gear oil may be? I have access to oils and greases to just about every specification around, hydraulic, power steering, auto transmission,cutting,high temp,extreme pressure oils. In fact a full range of oils from WRC rally cars to 220ton earthmovers, with everything inbetween. So I'm hoping I can save a trip to a dealer by finding the same spec oil at work.
Cheers all,
Cieran

 

[Its_Only_Money]

If its a 2-stroke it won't have an engine dip-stick will it? /forums/images/graemlins/confused.gif

 

[BarryH]

As Simon says.....sorry couldn't resist, The engine is a 2 stoke so won't have a dip stick.
The gear case oil has two threaded plugs. The lower one is the fill/drain while the upper one is the level. So fill it from the bottom and wait util you get a steady stream from the top. Fit the level plug then fit the lower one.

You'd be best getting your gearcase oil from a dealer as they come in handy tubes or a pump bottle that makes filling so much easier.

 

[plk987]

just changed the oil on my mercury blue band...it's a really messy job. It's good to have a spare pair of hands to put a thumb over the top hole while you try and change oil bottles or get the bottom plug in. If you don't all the oil just pours out.

And be very careful with the bottom drain plug, it is very soft and can be easily damaged or threaded

 

[cieranc]

2 stroke?? Hmmm.... Someone here told me it was four. Its a Belgium build, serial number 9007542. Suppose I'll find out when I run it! Any ideas what grade/spec of oil may be for lower unit?

 

[ares_apollo]

Someone is trying to pull a funny here! Naturally, the laws of physics show that the bottom plug is the drain and the top one the fill. and you should fill it until it starts to come out there.

 

[BrendanS]

well you do it your way, and the people who know what they are talking about will continue to fill from the bottom hole. It's your choice

 

[VicS]

Brendan

You are quite right as always BUT I have a brass syringe with a capacity I suppose somewhere between 50 & 100 cc with a long delivery tube of a small enough OD to fit through the "level hole". My prefered method now is to use that, after warming the oil a little, to fill through the upper hole. It saves fumbling with the drain plug, while oil is trying to run out, with the risk of getting it cross threaded and generally means a lot less mess to clear up.

So I will continue to do it my way.

 

[BrendanS]

The difference is that you know the correct method, but choose not to follow it for your own reasons, rather than try to claim that the correct method is in fact incorrect

 

[plk987]

The service manuals recommend the quiksilver gear lube which I got from Gaelforce, but our local marine engineer recommended a standard gear oil...I think it had 80 grade on the front. I don't think there is anything special.

 

[BarryH]

You would have thought, but its oil were talking about so doesn't flow like, say water, so the bubbles will rise with the filling oil. If you filled from the top you'd get air pockets. So even if the oil was coming out of the top hole you would not have enough oiul in there.

Quicksilver do a very handy pump that fits theirs, and others, oil containers. The screw fitting is the right size and thread for the gearcase hole. It makes filling easy and clean. Once the oil is up to the correct level you refit the level plug then unscrew the pump fitting from the lower hole and then refit the plug.

 

[cieranc]

Cheers PLK, I'll use a standard automotive gearoil, perhaps an EP oil as its a sealed unit, and may add a small amount of duckoil or similar penetrating oil to act as a water dissipant. I can sharp knock a hydraulic pipe up with a fitting to suit the fill hole, and attach the other end to a grease gun. Cheers guys, thats another little query answered! Where might be the best place on t'internet to get a new plug, the old one looks well busted, will probably have to drill it out. My buisness demands mean I won't really get opportunity to get to my nearest dealer.

 

[jfm]

Hmmmm. I'd use proper mercury oil. It is designed to run very cold unlike normal gearoils. The lower unit is heavily water cooled. It also contains additiives designed to allow it to work ok-ish with a fairly heavy water content, without which your engine will be more likely to be a write off if you get seal failure. As others have said you must fill from the bottom else you will get airpockets trapped

The fill plug is available from various online parts places. If you are making a filler gadget the thread is imperial (as is the whole engine)