Changing gear lube while afloat

E

Edward Thieme

New member
I take long trips and travel slow so the last trip lasted a year and put 1000hrs on the 135hp Honda. I had the boat hauled once to have the gear lube changed but it should be done about every 100 hrs.

I did this experiment at home to see if I could change the gear lube in the water. With the boat on the trailer I drained all the gear lube then raised the motor almost all the way, turned it left all the way and was able to pump all the gear lube back in without any coming out the top vent. To drain it just turn the motor all the way to the right.

This means on the next trip I can change the gear lube by moving my dinghy under the outboard and draining and filling the gear lube in the bottom of the dinghy. I change the prop with the dinghy the same way so nothing can be dropped in the water. I wish I thought of this sooner, I don't know if this will work with other boats and motors, I have the 25ft C-Dory.

ED on "Rambler"
 
Hi Ed,

If none of the new lube comes out the vent, how do you know when you have enough lube pumped in? Are you just putting in a known quantity?

Have you worked out a way to change the motor oil on the water?

Thanks,

Rob
 
Changing motor oil in the water is not a major issue, since there are many systems which will pump out the oil thru the dipstick or send a small tube down thru the dipstick. This is often done. The filter can be changed with plenty of oil adsorb pads and plastic bags. You may leave a little old oil in the engine, but not a major issue.

The other side of the coin, is the changing of oil or gear lube on the basis of hours at XXXX RPM or the amount of fuel burned. Many engines which are run at low RPM and % or output will use the amount of fuel burned as a gauge rather than hours.
 
Ed,
To each his own but I have always changed the oil in the lower unit as an annual event regardless of hours. Mostly to make sure it had no water in it that would freeze and break the lower unit's casting. If you are just cruising pretty slow I would ask the Honda dealer his/ her thoughts about using a synthetic to extend your oil change intervals. Or if your slow operation would allow for more extended lower unit intervals. If a synthetic gear oil works in a car I can't imagine the water cooled lower unit would be an more demanding except for the gear shifting into forward and reverse. I would however make sure the lower unit has a magnetic drain plug. If you pulled that drain plug and the magnet was just the usual little hair with no feelable chips, I would not worry about it. No milky look to the oil, no feeling of chips I would ride on until you could get to a place where you could do it on the hard. Since most oil levels are based with the motor being vertical or so I thought. I think determining proper levels in both the lower unit and the crankcase might be hard to determine with the boat floating. In our Honda cars I change oil just once a year using Mobil One. About 15,000 miles. I see no ill effects. I don't have to add much, they will use a little more in the winter.
D.D.
 
Sounds somewhat feasible but I would have to test it out to be sure. I was told by a good Honda guy that ours could not be done "well" in the water but could possible be done incompletely on our 90s. He also noted that checking the condition of the oil (water intrusion) could be done at the change interval and the actual change may be extended as needed without undue trouble. He basically said that we could double the interval if the oil looked un-compromised.
 
While it can be done safely, as you change oil over water, remember that any sheen on navigable waters of the US must be reported to the Coast Guard. No matter how much is spilled, or what damage is done, there is potential criminal liability for any spill, no matter how small.
 
After I pumped all the oil that drained back into the gear box and moved the motor vertical, to see if I was at the proper level, I tilted the motor again and after a few more pumps of gear lube it came out the level plug while the motor was tilted. Unless you measure you will put a little extra oil in the gear box. I guess measuring the oil quantity would be the best way to do it.

As far as spilling gear lube in the water, the bottom of the outboard is in the dinghy while changing oil so any spill is in the dinghy. The only problem would be if one of the plugs came loose after I finished but that could happen when the lube was changed on the hard.

I do suck the engine oil out the dip stick, even with the boat on the trailer, it is less messy than draining it and since I never open the drain plug it should never leak.

Ed on "Rambler"
 
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