Lower unit lube

J

Jon - CLou

New member
What's your favorite brand of lube for lubing your outboard lower end unit?

Currently I'm using Mercury high performance lube, but I would like to know if there's better.

Thanks, Jon
 
I'm using the same lube, the bluish colored fluid. I've had good luck with it, and the Merc dealer where I buy it in PA says it is great at keeping water damage to a minimum if you do have a seal failure. I change it twice a year.
 
I suspect that all of the "Branded" lubes are made for the specific engine manufactuer by one of the oil companies. I have generally used either the engine specific lube or Pennzoil brand lower unit lube. Pennzoil has a variety of lower unit oils. There is the GL4 Ourboard Gear Lube, the High Viscosity Lower Unit Gear Lube (GL 5 & 90 Hypoid oil spec) and Pennzoil 100% synthetic Lower Unit gear lube. Some of the older lower units used ATF.

Currently I am using the Suzuki brand, since the engine is under warantee for 6 years--I prefer to document that I have used their product. It probably is more important that the oil be changed regularly and checked for water, than the actual brand, as long as you have the proper oil.
 
I am a real bug about using ONLY the lubs packaged by the motor maker. The small difference in cost is not worth the worry of do I have the right stuff.

My two conts worth.
 
I learned some thing this week about the lower lube. when you go to repace the lube in the lower unit of the honda, there are nylon washers on all the drain plugs. These are not to be used again. they are one time use items. they do not reseal very well. I had done my own service up until this point and when I sent the boat in to les his guys fond a little ,very little, water in the lower case lube. hes said it was because of me reusing the washers. so repalce your washers.
 
Very good point, Tom. Also pay attention to your torque values when tightening the lower unit screws and oil drain plug. I have a bad habit of over tightening bolts and screws and paying for it later.

Today I purchased a torque wrench and it's amazing how little torque you need on these under water fasteners.
 
Notes on gearcase oil changes:

I agree with most of the above posts.

I would use the manufacturers lube if they package their own and if they have a 'synthetic' or 'extreme service' use that.

Otherwise, use Pennzoil or other top brands matching the recommendation from your owners manual.

Yes, do get new plug gaskets and use a torque wrench.

Use a gear-oil pump (Lubrimatic, fits a 1 qt bottle and has a screw-in fitting on the end of the hose), and fill gearcases from the bottom till the oil runs out the top hole(vent). Then put in the top(vent) plug, remove the pump fitting, and put in the drain plug. By putting in the top plug first, very little oil runs out while removing the pump and installing the plug. Then torque both plugs.

It is important to fill the gear case completely from the bottom to purge any air. If the gearcase is not filled completely the top bearing on the driveshaft can run dry and fail.
 
At least the Suzuki and Yahama 4 strokes have washers on the engine oil which also need to be replaced with each change, as well as the lower units nylon washers. I buy a dozen at a time, so I will always have new ones. Agree with Torque wrenches for tightening.
 
I'm preparing to do the 20 hour maintenance on my pair of BF50 Honda outboards. Does anybody know what size nylon washers the BF50 requires on the lower unit plugs? Also, how much torque should be applied to the plug screws when re-fitting them?

Also, I'm curious about what sort of store will sell the gear oil I require. The local West Marine (Edmonds) just has their own brand, and I'd really rather purchase either Honda specific gear oil or something by one of the well known manufacturers. Any suggestions?

I've got a service manual on order but any info anybody could give me on these items would be greatly appreciated. Thanks!

Alec
 
Do the torque wrenches come with screw driver tips or just socket type? THe Honda's don't have a hex hed type screw but do have a philips head. Makes it hard to loosen them it seems.
 
theres better /without gettin to techinical i'll just say AMSOIL i've abused a lot of lowers and have seen differences when tearing down for re-builds.i swear by it .not knocking mercs oil but u asked for better. ..john
 
Alec,

Why don't you have your dealer do the 20 hour service?

If you have any warranty problems later it will be much easier to deal with if you have proof that the dealer did the service..

The dealer service techs know what to do and what to look for on the 20 hour service. That service is a chance for the factory trained techs to verify that your motor is operating properly.

If you are still going to do your own service, buy the oil and plug gaskets from the dealer. Also buy a gear oil pump and fill the lower unit from the bottom up. Find out what the correct torque is for the screws. Don't forget to buy a torque wrench!

If you strip the drain and fill plugs, that's not a warranty item and could cost you a new lower unit housing and the labor to install it. If that happens, you will only have a shop warranty (maybe 90 days) on the rebuilt lower units. If you don't tighten the plugs enough, and water gets in, you have to pay for the repair. (your failures are not covered by warranty)

Have I convinced you to have the dealer do the service? In my opinion, the amount of money you could save by doing your own 20 hr service is not worth risking damage to the lower units and not having warranty coverage.

Larry H

Retired outboard mechanic.
 
Spencer,

Torque wrenches have a square stud either 3/8in or 1/2in onto which you install the correct socket. Sockets are available with screwdriver tips, both phillips and straight. Check a good auto parts store or Sears. Buy a quality socket. Cheap ones will strip themselves.

Be sure that the tip fits the screw, too small a tip can strip out either the screw head or damage the tip.

PS: See the post above to Alec.

Larry H

Retired outboard mechanic.
 
I agree with Larry especially on the 20 hour service. I had a local dealer do it and they changed everything but the gel coat. It was close to $400. There are a lot of things the tinkerer link myself wouldn't notice and the security of knowing someone knowing what to look for is worth the extra expense and inconvenience. Future oil changes I plan to do myself. In the Suzuki owners manual it suggest changing the oil filter every other oil change. Does anybody actually change the oil without changing the filter. I'm also a big fan of Amsoil first because I think it's a very good product and secondly it's so easy to get. Just a phone call and it's at my door in usually two days. Expense is about the same.
 
Hi Larry,

Larry H":18lmksnh said:
Alec,

Why don't you have your dealer do the 20 hour service?

If you have any warranty problems later it will be much easier to deal with if you have proof that the dealer did the service..

The dealer service techs know what to do and what to look for on the 20 hour service. That service is a chance for the factory trained techs to verify that your motor is operating properly.

If you are still going to do your own service, buy the oil and plug gaskets from the dealer. Also buy a gear oil pump and fill the lower unit from the bottom up. Find out what the correct torque is for the screws. Don't forget to buy a torque wrench!

If you strip the drain and fill plugs, that's not a warranty item and could cost you a new lower unit housing and the labor to install it. If that happens, you will only have a shop warranty (maybe 90 days) on the rebuilt lower units. If you don't tighten the plugs enough, and water gets in, you have to pay for the repair. (your failures are not covered by warranty)

Have I convinced you to have the dealer do the service? In my opinion, the amount of money you could save by doing your own 20 hr service is not worth risking damage to the lower units and not having warranty coverage.

Larry H

Retired outboard mechanic.
Click to expand...

Well, aside from knowing what failures to look for on the 20 hour service, you really seem to be recommending that I have all of my services done by a dealer mechanic, since failure to tighten the plugs properly is something that has nothing intrinsically to do with the 20 hour service. While I respect your clearly expert opinion, $400/engine/service is a pretty steep price to pay for an assurance that the Honda warranty specifically says I do not need:

(Quoting the Honda warranty):

As the outboard engine owner, you are responsible for the performance of the required maintenance listed in your owner's manual. American Honda Motor Co., Inc. recommends that you retain all receipts covering maintenance on your outboard engine, but American Honda Motor Co., Inc. cannot deny warranty solely for the lack of receipts or your failure to ensure the performance of all scheduled maintenance.
Click to expand...

Which essentially says that as long as you do what the service manual says, that is not grounds for denial of warranty coverage. I've been doing this sort of outboard maintenance on my engines for ages, so I'm not concerned about being able to do the work properly. Really just wondering about things to look for (like the nylon washers, other lower unit lube changes I've done have only encountered O-rings, which are generally good for more than one installation).

However, I think your general point is to not cut corners, use all of the right tools for the job, and use factory-approved parts and materials, which is all extremely useful and relevant advice.

In terms of what to look for and check, this is the sort of information that exists in other outboard shop manuals I've gotten in the past, and am quite sure it will be present in the Honda one when it arrives. However, the primary reason for the query here was to find out what pitfalls others have run into when performing these services on their Hondas. I've found a lot of great info in old threads (like this one) but if there are any other things to watch out for that would be much appreciated.

Thanks!

Alec
 
I also do all my own serviceing including valve adjustments and carb synchronization. I took mine in for their first service (15-20 hrs) because they hook it up to their computer for one thing and examine the running characteristics for anything out of whack. It was useful and reassuring even though no problems found.

They also said I could save some $$ by skipping the spark plug changing and a few other items, they can actually wait till the 100 hr service. But DO have them change the lower end oil, not many hours, but will uncover what could be a serious water leak that could ruin your day. My bill was about $150 total for BOTH engines (5 yrs ago). My 2c.
 
Dora~Jean":1k9iukt1 said:
I also do all my own serviceing including valve adjustments and carb synchronization. I took mine in for their first service (15-20 hrs) because they hook it up to their computer for one thing and examine the running characteristics for anything out of whack. It was useful and reassuring even though no problems found.

They also said I could save some $$ by skipping the plug changing and a few other items, they can actually wait till the 100 hr service. My bill was about $150 total for BOTH engines. My 2c.
Click to expand...

Hmm, perhaps I'm being misled on the costs. $150 for both engines for the 20 hour service seems quite reasonable. I should talk to some other dealers about what it would cost, because you all do raise good points about making sure it's all working. Can anybody share with me what they've paid in the past for the 20 hour service on a pair of Honda BF50A engines?
 
Alec,

No slight intended on your skills.

The motors are yours and you should do what you think best.

I wanted you to be aware that if you make any errors, warranty probably won't cover the results.

$400 per motor for service seems high. That would be about 3 hours at $100 per hour plus $100 in parts per motor. $400 total for both motors still seems high, I wonder what the mechanic would do for those 3 hours?

You might want to give E Q Marine a call. Les has a good reputation.

Larry H
 
I don't think Amsoil sells from stores but if you goggle it you'll get and on line distributor in your area. http://www.amsoil.com/ You sign up for a preferred customer account which I think is about $10 a year which saves you a little on your purchases. I use it in all my garden equipment, home generator and motorcycles and have been using it in the Mercury outboard. When I put in and order it usually shows up in two or three days. They have special grades especially formulated for outboards (according to the advertisement) with corrosion inhibitors. I don't know if it's any better than any of the other synthetic oils but the convenience factor of having it delivered to your door is nice.
 
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