Flush neccesary when switching to Amsiol??
 

I currently have Merc HP gear lube in my XZ drives. I'm switching to Amsoil Marine 75-80/90. Can I just drain the old lube or do I need to flush it somehow before putting in the new Amsoil?

I can't believe it, I was just quoted $76.00 for a case of Amsoil Marine Gear Lube! Kinda makes me wonder... does this sound right? Seems way too cheap.

Sounds about right.

I pay $72.00 for a case of six quarts of Royal Purple as a resale dealer.

Anyone? Simple drain or do I need to flush? If I need to flush how do I do it?

If your old gear lube was not to bad I would just refill with new and be done with it.

The oil is good, just doing the annual maintenance and wanted to make sure the two lubes were compatible. I don't want to have sludge or something develop.

If you didnt need to flush the old oil, theres no need to flush when going to amsoil synthetics. It will also mix with mineral oil. Im a 15 yr dealer, your drive will be very happy!!! :D

Thank you for a definitive answer! My local dealers didn't seem to know much about marine applications. Looking forward to trying it out as soon as I get my delivery.

I also use Amsoil products.

Do you guys think their Marine gear oil is better then the Merc HP Syn?

I was told the Syn Merc stuff is the best.

Mercs oil didnt even make the top 5 from independent testing.

My testing was on #3 speedmasters with all large shafts running 1100+hp. With the Merc oil we would burn up bearings and gears under 50 hrs. Changed to Amsoil and NEVER hurt a bearing again 150+ hrs at very high input shaft speeds. 1-1 gear ratio turning them 5700-6000 for up to 25 miles. The merc oil would puke out the vents @ 4-5 miles because of the heat.. Im sure everyone has a opinion but I run amsoil in everything I own, with great results!! The drives are still around :ernaehrung004:

Thanks for the numbers, very impressive IMO. Glad I'm making the switch. I don't punish my drives by any means but I really can't afford to rebuild/replace drives every year or two like a lot of these guys talk about. By the way... nice lookin set up.

Thanks no problem!!! I dont own the drives but there still around and I think up for sale.These are what I run now.

Is the Merc HP Syn gear oil 75w-90 or 50w? I cant find any specs on it. I was told it is a 50 weight oil. Is the 75w-90 to thick for the dravo-1 or the xr? Have you tested the Royal Purple? Im getting ready to install my new xr-upper and the Imco sportsmaster lower. I want the best oil possible!
This is a single engine boat with bravo-1 and I never had any problems. So I put in my new engine, close to 600hp.
I put 9.5 hrs on the new engine and had to put the boat up for winter. Then I went to do all my service work. When I pulled the drain plug for the outdrive the oil had a bad burnt smell.
It had never smelled like this before and its only had the Mercury hp syn.oil in it. I have always changed
the oil every 20hrs. The new engine did it and thats ok but I want the best oil money can buy for my new xr.
Any help on this would be great. Sorry for all the questions but I need some info on this. Thanks, Timmy Farmer.

Looks like Amsoil is going in my B1. I use their gear and engine oil in everything else I own.

Drain the gear oil completely and fill from the bottom up no need to flush but just wondering what were you going to flush with? Hopefully flushing with the new gear oil being used. Run the amsoil severe gear 75w-110 better than the amsoil 75/80w-90 marine gear oil. also Teague runs the amsoil 75-110 servere gear oil. He had a lot of input with amsoil for the devolpment. Alot of stuff today off the shelf motor oil and gear oils are not a true synthetic oil they are just group III's base oils and the additives are thrown into the mix that are counting it as a synthetic. Also I can look up what weight the merc hi-perf gear oil is I had it tested but forgot the specs. Not a very strong oil compare to others. A friend of mine is a oil chemist and a oil analysist for leading race teams around the world plus some teams in the NHRA, Nascar and motorcycle road race teams. No bull so i am well schooled in the oil game. Also the Volvo Penta syn. gear oil tested better than the merc hi-perf . Amsoil use to be one of the best about 10 years ago and back but gone down hill some what but the last 2 years are stepping it up once again. One thing it did was oxidized very easy not very good for wear protection and corrosion protection ( FYI ). Some more info one of the best motor oils that I was testing came from VP Racing the ones who make racing gas, high octane gas and nitro for the top fuel race teams. The problem is they no longer make it as of last year. It was kind of hush info in the racing fields. Also I know this is my first post here but have been in the boat biz since 1991 and around boats, bikes and drag cars my whole life. You got to start some time.

Boats Unlimited, thanks for the info. Glad to have you on the board. As for the flush... everyone tells me I don't have to worry about it (but I would have flushed it with new Amsoil from the bottom and drained) so I'm not going to bother. As for Severe Gear Lube, I don't see that they claim it's for outdrive applications on the Amsoil webpage so I ordered the Marine 75/80-90. If I find out Severe Gear is recommended for outdrives I'll go with it next change.

Thanks again. I would really like to know about the mercury
gear oil weight if you get a chance.
Timmy.

My idea of a simple way would be to change to new oil and run it a short time then change the oil again ...more $$ but what else is cheap in this sport? m

I switched over to 75w90 royal purple, just drained and filled from the drive.....works great !

The Merc Hi-perf gear oil is a 80w-90 weight and has a viscosity of a 30w or 40w but i do not remember and this is going off the top of my head. I will try to find it and post it for sure. I had a ton of motor and gear oils sent out for testing new and used with the same amount time on them. I filed all the reports away. As far as using a recommended gear oil that does not say marine on it i will post some info about that later. Most recommended oils are going to do a good job on stock and medium horsepower applications so if you are using a name brand sure its going to work but most likely you are not sending samples off to get tested by an oil analysis expert who does this day in and day out. Another thing I see so many pics here of peoples boats and motors using Fram oil filters. Sorry people one of the worst cheapest quality oil filters you can be using for any motor more or less a marine motor. #1 these filters are not made for higher RPMs motors unless you are using their HP filters but even then they are changed after every race or in between rounds in the racing world something non racers should have to do. #2 cut a fram filter open, cut a wix filter open, cut a Amsoil EaO filter open and then get back to me. You will throw that Fram in the trash I promise. Fram uses cardboard end caps instead of steel also the filter media is not uniform are the 2 biggest reasons among some other things which I do not want to make this a story book. If you have an engine buider or engine guy and he is using Fram oil filters he needs to do some more home work period. Like I said buy as many brands as you want cut them open at the base pull them apart and will thank me for adding some longevity to your motor. Off The shelf motor oil filters Amoils EoA and the EoA brand is important. This is one of the best. Wix is good and Baldwin not bad either. Mr. Dock Holiday I hope you are not using those Fram oil filters on your new motors? your old motors said Fram all over it. I SEE NOW WIX good for you. Anyways NICE MAKE - OVER a job well done. I did not send in Royal Purple gear oil but I did send in their motor oil. It was just middle of the road not bad but not strong either. Also not a full syn either falls mostly under a conventional oil. Their Racing oil is different but you would need to change it every 10 to 25 hours at the least because it does not use a full additive package for extended use (FYI ) Yes I know this my second post so most of you 6,000 posters are going to throw that out there. I have lurked on this sight for years and years, met the first start up/owner of OSO at an APBA offshore race many years ago. Just because you have 6,000 post does make you an expert about anything. I see this thrown around here alot also about someone who has very low posts.

here is the techical report on Merc Hi-Perf gear oil. Kinenatic Viscositics CST 100c = 15.1 so that means by SAE standards its a 90w gear oil which also compares to a SAE 40w engine oil. So to answer your question 40w. also Mercruser 25w-40 engine oil also compares to a SAE 40w. The SAE tests for this is, oil is heated to 212 degrees fahrenheit (100c) compares and times its flow rates to determine its weight. This is a very very short explaination of how and determining oil weghts are down.

Here is a comparitive viscosity table. If you have any questions, ask.

Ken

I have been using the amsoil marine lube for the last few year trouble free. I did not flush the drive and I did not have any problems. I became a dealer a few years back and I use it in everything.

I also put in 600 hp motors and have the same problem with oil smelling burnt after a few hours. Will amsoil alleviate this problem?? I am also pursuing better drive showers.

See post 10 and let me know!! :drink:

Which weight do you recommend?? I'll try it!

worth every drop!!!!

post 15 amsoil SG 75w-110 a little better oil for abuse.

Over kill for 600 HP.

I just got hooked up to be a Amsoil dealer.
I couldnt find one in our town so it looks like Im going to put it in everything.

Smart move and you might make some$$$ 15yrs and I even run it in mowers!! :D

Searched Amsoil flush and found this thread.
I used to try to run my boat before a yearly drive oil change to warm the oil before draining it and someone on the sandbar said once switched to Amsoil that wouldn't be necessary...any thoughts?

what's is everyone running for motor oil in a HP500 EFI

I run AMSOIL 15w-50 Dominator Racing Oil in my 496ho's.

I am new to performance boating, but I am reading so much about all the gear lubes and I have a serious question that comes to mind. As I understand the bravo has cone clutches. I had installed a auburn diff in my mustang and it had cone clutches in it, Auburn says they will not warranty the diff if used with any syn gear oils. They claim it polishes the clutches to a point they will not grab. I always used royal purple throughout and ran my car very hard eveytime I drove it, was a second car. I ran that car for over 140,000 miles no problems. So are the clutches in the bravo subject to the same polishing effects?

Sorry it was not the cone clutches it was the harden gears Auburn gear claim it polishes.

I switched to Amsoil in my motors and love it. Question....how does the Amsoil severe oil compare to the Torco oil recommended by Merc and Imco?

Imco recommends Amsoil severe gear in the SC'c, unless they changed there mind in the last few months. I can call to see what they recommend in the SCX's. But would surprised if its anything but Amsoil
Torco in the 6 drives not bravos

A friend of ours got the SCX uppers and in bold red letters on the paperwork it says to use Torco or high quality synthetic gear lube.

Update...Spoke with IMCO yesterday and they recommend TORCO in their SC and SCX drives. They said AMSOIL can be used as well.