Any advice on gear oil on a mercruiser

[Bathdave]

New to this boat owning and loving it but still very naive but learning...have a mercruiser 5.0 on a Maxum from 2000.

Had it fully serviced and spent quite a lot a couple of months ago.. Out yesterday and engine alarm went off. No idea initially ( never got an owners manual with it!) but tracked it down to low level of gear oil in reservoir, found half a bottle topped it up, hey presto alarm stopped and ran smoothly home.

So here's the question.. After 2 months and maybe 30 hours, should it have run down that much? Do I need to top it up constantly or is it symptomatic of a bigger ( ie more pound notes!) ?

Appreciate any advice from the oracle that is YBW

 

[dpb]

Not unususal to drop off a little after a service, but if it goes on needing a top off then something is amiss. Now you have refilled keep an eye on it and see what happens.

 

[lovezoo]

Its normal that after changing the oil in the outdrive, the monitor bottle level can drop as air pockets work their way out. The problem arises if it keeps dropping, so I would just keep an eye on it.

 

[markcw]

I would of thought you should not be loosing a drop, my v/p 290 leg does not loose any, I would do you checks and retop it up and then watch it carefully, the other thing is the leak if one could be getting burnt off throught the exhaust side of the system, if your exhaust vents through the prop,

I can recommend marineengine.com and choose the merc forum.

 

[VicS]

never got an owners manual with it!

Appreciate any advice from the oracle that is YBW

Download an owners manual from http://download.brunswick-marine.com/download/main;jsessionid=105vjo07c1lcd?type=corp

 

[paultallett]

New to this boat owning and loving it but still very naive but learning...have a mercruiser 5.0 on a Maxum from 2000.

Had it fully serviced and spent quite a lot a couple of months ago.. Out yesterday and engine alarm went off. No idea initially ( never got an owners manual with it!) but tracked it down to low level of gear oil in reservoir, found half a bottle topped it up, hey presto alarm stopped and ran smoothly home.

So here's the question.. After 2 months and maybe 30 hours, should it have run down that much? Do I need to top it up constantly or is it symptomatic of a bigger ( ie more pound notes!) ?

Appreciate any advice from the oracle that is YBW

Mercruisers have the 'burp' bottle so air can work it's way out after a fill and you can see if the leg is loosing oil.

Yes the level will drop after a service as air works it way out but I've never know the bottle to empty before. Now you have topped it off again, keep a very close eye on it. The level will move a very small amount as the boat is run, but when cold should retrun back to the original level. If you have another serious drop in fluid I would say you have a leak and it must be sorted.

Good luck and let us know how it goes.

 

[lovezoo]

I would of thought you should not be loosing a drop, my v/p 290 leg does not loose any, I would do you checks and retop it up and then watch it carefully, the other thing is the leak if one could be getting burnt off throught the exhaust side of the system, if your exhaust vents through the prop,

I can recommend marineengine.com and choose the merc forum.

Its a Mercruiser not a VP.

 

[VicS]

Its a Mercruiser not a VP.

That's why he suggested the Mercruiser forum at MarineEngine.com

http://www.marineengine.com/boat-forum/forum.php

I'd suggest the Mercruiser form at iBoats

http://forums.iboats.com/forum.php

 

[Spi D]

...found half a bottle topped it up, hey presto alarm stopped and ran smoothly home.

Hopefully that bottle matched the recommended specs for gear oil.

Any grease is better than no grease at all, but except from emergencies oil specs are to be taken seriously.

 

[jhr]

Just to repeat what everyone else has said, this is absolutely normal with a Merc leg after the gear oil has been changed. The first time it happened to me, I absolutely crapped myself, but it didn't need re-filling again after I'd topped it up (it had dropped to about half way down the bottle) and the same thing has happened with each subsequent oil change.

By all means monitor the level - it's good practice anyway - but I doubt you'll have further problems.

 

[lovezoo]

That's why he suggested the Mercruiser forum at MarineEngine.coml

But he was comparing the Mercruiser to his VP which has a different procedure for oil changes and hence can't be compared to the Merc.

 

[MapisM]

Just to repeat what everyone else has said, this is absolutely normal with a Merc leg after the gear oil has been changed.

Just to throw in my 2c, it might be absolutely normal if you guys use mickey mouse mechanics for servicing your outdrives.

The correct procedure is to refill the drive pumping (with a specific pump kit) the oil from the bottom of the drive, and let it work its way up to the reservoir.
This is made specifically to avoid air bubbles to get stuck inside the drive, because if they do, the risk is that they could stay there long enough to damage the drive.
Mercury indeed suggests, after the refill, to use the boat for a while and re-check the reservoir level, just in case.
But the last time I changed the gear oil in a Bravo outdrive, I didn't have to add one single drop of oil afterwards.
The OP surely has an Alpha, considering the 5.0 engine, but the procedure is the same and I very much doubt that the final result could be different, if followed properly.

Anyway, in the OP boots, if as I understand the maintenance history is unknown, I would change all the drive oil ASAP (and obviously with the proper procedure), and keep it monitored after that.
3 liters of oil is a cheap insurance for an outdrive, even if afterwards a leak would become evident, requiring to throw it away.
Btw, not only is unnecessary, but even not recommendable to use the specific Mercury green stuff which they sell at stupid prices.
An oil change is a good opportunity to switch to a good synthetic oil with proper specs (I used the Mobilube 1 SHC 75W-90 for instance).
Still not cheap, but more reasonably priced and actually better.

 

[volvopaul]

New to this boat owning and loving it but still very naive but learning...have a mercruiser 5.0 on a Maxum from 2000.

Had it fully serviced and spent quite a lot a couple of months ago.. Out yesterday and engine alarm went off. No idea initially ( never got an owners manual with it!) but tracked it down to low level of gear oil in reservoir, found half a bottle topped it up, hey presto alarm stopped and ran smoothly home.

So here's the question.. After 2 months and maybe 30 hours, should it have run down that much? Do I need to top it up constantly or is it symptomatic of a bigger ( ie more pound notes!) ?

Appreciate any advice from the oracle that is YBW

After a service the level will drop slightly, I often revisit the next day to check, or be there at boat launch to see all is well.

If the level keeps dropping you have a problem. Not necessarily with the seals on the leg as I've replaced many plastic through transom shield feed pipes as they go brittle after a few years. Also the pipe is often held in place with aplastic tie wrap! Pants idea I know.

Take a look at the drive in still water to see if any oil droplets float to the surface.

Buy merc oil or a good fully synthetic oil.

 

[Jurgen]

Had to top my oil reservoir up after a 5 hour trip from Southampton back to Brixham. The alarm was going off but after speaking to the engineer who serviced the leg prior to departure I was re assured.

After topping up the problem has gone.

Be warned though, DO NOT OVERFILL I have seen the results of this and it's not pretty lol

 

[Bathdave]

Thanks guys some pretty consistent and encouraging advice...I did just have a full engine and drive service, so I will talk to the engineer who did it as well to get his take on it it, but as I said in My original post, I am new to this and very unsure of all the technical stuff, so it is really helpful to get the input of the experienced salts who frequent these pages.

I will definitely monitor closely before each trip!!

 

[rafiki_]

I have had my Merc Alpha drive's serviced twice, and never had to top up the reservoir on either leg.

 

[MapisM]

Glad to hear that someone else shares my experience.
I began wondering if there isn't any difference between Bravos and Alphas when I saw the reply from volvopaul, because I know he's not the type of engineer who would use a wrong procedure to refill a drive.
Incidentally (and I'm speaking to him, since he included the Merc oil in his recommendation, while I suggested the opposite), I understood from a US performance boats forum that the Merc oil is also known as "green death".
The main reason is that it tends to develop muddy residuals which can lock the bottom of the reservoir, hence making the reservoir itself useless, because in case of a leak, its content doesn't flow down and leaves the drive quietly draining the oil without any warning.
Of course, this is even more critical when the drive is mated to crazy power supercharged big blocks (as they often do in the US), but it's still something I'd rather not have in my drive anyway. Actually, I thought they were exaggerating a bit when I first read those reports, till I checked my reservoir and found what you can see in the pic below.
That's the reason why, when I changed the oil myself ('cause my Merc engineer refused to do it with anything else than Merc oil), I used the Mobil 1. Never had any problem with it, in spite of the fact that the boat was run pretty hard, 'cause she was kept on a lake and only used for the occasional blasts...

 

[rafiki_]

Interesting MapisM. My techie will only use Merc parts, but is more casual about the oil. I will have a closer look at the reservoirs this weekend, but can't recall them looking like yours. How old is the drive?

 

[paultallett]

Interesting what you say MapisM.

I've got Bravo III drive and have watched my tech fill it before, using proper pump and taking his time so allowing the air to be forced up. Always after the first run out the bottle will have lost 5mm ish of fluid, but then once topped up stays still.

I've never lost a lot of fluid and the alarm has never gone off. What else would you suggest to make sure the fill is fully done with all air expelled??

 

[MapisM]

Interesting MapisM. My techie will only use Merc parts, but is more casual about the oil. I will have a closer look at the reservoirs this weekend, but can't recall them looking like yours. How old is the drive?

The drive was (boat now sold) a Bravo I XR, mated to a 496HO, and at the time I took the pics it was 3 years old but with only 100 hours or so.
Mind, other than the muddy deposit, the oil actually looked pretty good, not milky at all, and I didn't find any metallic bits when I changed it, so I can't say it didn't do its job.
But surely the bottle bottom did look scary.