[burnsy111]

I bought a used 15 hp 1985 from someone who I thought was trustworthy.
He said engine iwas serviced and ready to run, I did start and test in tank in neutral only. I checked lower unit oil to be on safe side and realized it was not at top of vent plug. I removed drain plug and discovered that the hole was basically welded closed or filled with an epoxy. My guess is that previous owner stripped threads and did this as a cheap fix. 2 Questions
Can I fill unit with oil through vent plug?
Did running it for 5 minutes in tank in neutral cause damage to water pump or lower unit since it had no oil.?
I took it to a local mechanic and he said my only option would be to replace lower unit since filling from vent hole would not allow air to escape.
Appreciate any advice
Thanks

[WillyBWright]

I'm not particularly concerned about the water pump. It's separate from the gearlube altogether. This'll be terribly inconvenient but it will work...you can remove the gearcase and remove the driveshaft to both drain and fill the gearlube. Remove the upper vent screw as well. Invert the gearcase to drain it and then put it back upright and fill through the driveshaft hole til it comes out the vent. You'll need a foot of small hose attached to the gearlube bottle to guarantee that you get the gearlube down inside the bullet. Put the hose down into the driveshaft hole til you know you're well down inside and force the gearlube through it til it comes out the vent. Put the driveshaft back in, put the vent plug back in, and reinstall the gearcase. Service the water pump at the same time. If you're in there for the water pump anyhow, it's not such a big deal. But it sure is a lot to just change the gearlube.

To facilitate a quicker drain, it might be necessary to crack the shift pivot screw. It's a phillips-head screw down by the drain. Do NOT remove it, just back it off it's threads and leave it in there. It'll allow air in as the gearlube drops out. Otherise it might take hours to fully drain all the gearlube out. Don't forget to tighten it back up after it's drained.

[F_R]

Heck, just put a Heli-Coil (thread repair) in the screw hole. For just one repair, it would make sense to take it to an automotive machine shop and have them do it instead of shelling out the $ to buy a whole kit.

As for the 5 minutes, how long did the previous owner run it that way?

[burnsy111]

Thanks for the advice, I agree that would work but I want to avoid dropping lower unit if possible. I did crack the pivot screw and blew compressed air into the vent hole at the sam time. Air came out of the pivot screw hole with no sign of any gear lube. I think the lower unit is bone dry. Therefore I only need to add, not drain. Can I do your suggestion and just insert the tube through the vent hole as far as I Can and wait until I see lube come out the pivot screw hole, then tighten that and keep adding until it comes out the vent hole. About how much gear lube should the lower unit take?
I figure it might be worth a try as I will have to replace the lower unit and water pump anyway if prior owner ran it without lube in there.

[F_R]

You can use a pump type oiler can and just put it in the top plug very slowly. It will run downhill by gravity and fill from the bottom. Don' know the capacity offhand, but would guess it to be on the order of 10 oz.

I still say go get a heli coil put in it though. No need to drop the lower unit.

[burnsy111]

Originally Posted by WillyBWright

I'm not particularly concerned about the water pump. It's separate from the gearlube altogether. This'll be terribly inconvenient but it will work...you can remove the gearcase and remove the driveshaft to both drain and fill the gearlube. Remove the upper vent screw as well. Invert the gearcase to drain it and then put it back upright and fill through the driveshaft hole til it comes out the vent. You'll need a foot of small hose attached to the gearlube bottle to guarantee that you get the gearlube down inside the bullet. Put the hose down into the driveshaft hole til you know you're well down inside and force the gearlube through it til it comes out the vent. Put the driveshaft back in, put the vent plug back in, and reinstall the gearcase. Service the water pump at the same time. If you're in there for the water pump anyhow, it's not such a big deal. But it sure is a lot to just change the gearlube.

To facilitate a quicker drain, it might be necessary to crack the shift pivot screw. It's a phillips-head screw down by the drain. Do NOT remove it, just back it off it's threads and leave it in there. It'll allow air in as the gearlube drops out. Otherise it might take hours to fully drain all the gearlube out. Don't forget to tighten it back up after it's drained.

Can I just add lube through the vent hole without dropping lower unit since I dont have to drain because there appears to be no lube in there?

[WillyBWright]

No. You'll always have a bubble of air below. I suppose it's possible, but it could take hours or even maybe days.

[F_R]

Yep, a few drops at a time. That's why they put two plugs in it.