Can I use 75w-90 oil in the gear box?

[dannieboiz]

Do I have to use mercury 90 oil or can I use standard automative 75-90 or even 80-90 oil in the gear box of my 02' 15hp?

 

[Texasmark]

Re: Can I use 75w-90 oil in the gear box?

Depends on you, your engine, and your future desires. If you are lucky and can keep all water out of your LU then why not. If you can't and a little gets in and the engine sits for awhile then maybe not as the water will mark parts of the drive bearings and shafts causing LU noises and other problems. If you are unlucky and get water in your LU frequently and don't change your fluid regularly then no.

Lower unit oil has special additives that allow it to stick to the metallic parts thus providing a seal against water.

Your call, but for a few bucks you could be setting yourself up for a real problem. Remember sir, LUBE, proper lube at that, is your cheapest investment, regardless of the equipment.

HTH,
Mark

 

[Capt Ken]

Re: Can I use 75w-90 oil in the gear box?

Oh yeah. Plus if water should get in the lower, it turns to vanilla jello and near impossible to drain.

 

[Laddies]

Re: Can I use 75w-90 oil in the gear box?

Any GL 5 rated oil will work but marine gear lube contain extra additives

 

[dannieboiz]

Re: Can I use 75w-90 oil in the gear box?

Thanks guys, it wasn't about the few bucks, the closest west marine tobne is almost 20 miles away. I was just being lazy. I think I'll have to get my *** in the car.

 

[emckelvy]

Re: Can I use 75w-90 oil in the gear box?

Do you have a Wal-Mart nearby? Most stores have a small marine section within the hunting/sporting goods area, and they sell quart bottles of Hi-Vis marine gear oil, cheaper than a dlr, too.

NAPA usually has a small marine section as well, and if they don't have the oil in stock they usually can order it for you and have it the next day if it's in the warehouse.

You can also get a pump which will screw into the quart bottle, makes it a lot easier to do the refill.

HTH............ed

 

[Maxz695]

Re: Can I use 75w-90 oil in the gear box?

I use 90 weight Valvoline from Wallmart with no issues to date.

 

[dannieboiz]

Re: Can I use 75w-90 oil in the gear box?

I'll try Wally wotld and Napa first both are next to home. I think I'll try yo stick with marine grade.

 

[tazrig]

Re: Can I use 75w-90 oil in the gear box?

I'll try Wally wotld and Napa first both are next to home. I think I'll try yo stick with marine grade.

Worst case... iBoats delivers!

 

[wired247]

Re: Can I use 75w-90 oil in the gear box?

Thanks guys, it wasn't about the few bucks, the closest west marine tobne is almost 20 miles away. I was just being lazy. I think I'll have to get my *** in the car.

20 miles? The closest Marina to me is 75 miles. Wal Mart is 20 miles away but it and every other store in my town carry marine gear lube. Its more expensive than it should be but its worth the extra five bucks.

 

[oldman570]

Re: Can I use 75w-90 oil in the gear box?

I use strickly marine grade oil in my LU's . the regular automotive oil will expand when it get warm or hot and will put pressure on the seals and can blow them out. There is no vent to the outside and as the oil heats up it dose expand. This is why autos and trucks have breather vents on them. Marine grade oil has additives that inhibit the expandison of the oil. JMO
Oldman570

 

[Star]

Re: Can I use 75w-90 oil in the gear box?

Danny,
If that is a 02 15hp 4 stroke mercury you better use the best you can get!!!! The main drive shaft bearing dezign is weak with bushings and tiny needle bearings on the bottom. If it is not well lubricated it wipes out the gear and the lower case. It cost me close to $1000 to replace it. I am now changing out my oil 3 times a season.

 

[dannieboiz]

Re: Can I use 75w-90 oil in the gear box?

Thanks for the heads up. I only put maybe 30 hours on the motor a season. So I do it once a year