Bravo 3 drive noise in upper end

TikiHut2

I had a mysterious mechanical sound in my '04 Bravo 3 Merc drive so I pulled the drive last month and replaced the 9y/o Gimbel bearing. The gimbel bearing had one small spot when it was turned by hand that would seem to be a bit rough so I thought that'd do it, but it didn't. The U-joints were fine and we checked the alignment. While the tool didn't turn with two fingers for an ideal alignment it seemed fairly easy and not worth disturbing the motor mounts. There's no debris or water in the drive oil at the drain plug.

I ran the boat a few hours and it needed 2oz of drive oil but I figured it was just purging air/leakage in the line from removing the drive. Now the noise is persisting and sounds even more pronounced, especially in the top end of the drive. It's definitely a mechanical/gear sound in neutral or drive that I'm starting to feel queezy about the cost and whether I'm being over protective/paranoid or is it standard drive noise on a B3.

Any insight from those who've noticed OD gear noise when flushing a Bravo 3 drive on the hard?

Thanks, Mike

212rowboat

what kind of oil did you use?

TikiHut2

Always use OEM Merc gear oil.

Black_Diamond

The guy at All American Drives is good. I know he recommends a syn EP type oil (I use it in mine). He calls the Merc drive oil 'blue death'. lol. Check your drain plug for chips..a tell tale sign of trouble.

TikiHut2

Blue death....that's catchy.

Drain plug sample is free of debris and water but I'll check again tonight.

I've sent an email to the guys at All American Drives so we'll see if they have anything.

Black_Diamond

No debris is good.  I know spinning mine the upper is quiet so noise is not a good sign.

The Blue Death does have a nice ring to it

TikiHut2

U-joints were fine when I pulled the drive and the previous noise persists even after an oil change and new gimbel bearing. The noise even resonates when below in the cabin while I'm rinsing the engine on the muffs but it's not noticeable standing at the helm. I'll see if i can get a brief video right next to the top end when it's idling.

212rowboat

I don't know outdrives, Tiki, but I have a grip on ring and pinion relationships..

when there is wear enough to alter the contact, gears will howl and/or whine.. that speaks of evil things taking place in your rig... but, I mentioned oil because it will also cause a howl/whine if it's not getting in between the contact surfaces (yet)... thicker oil can cause this, but it generally loses viscosity as it warms, where as thinner oil will maintain viscosity better, but maybe be too thin on the top end..

is there any possibility you bumped that thing good enough to alter a shims position? they will hold fine as can be whilst under pressure, but will often dance when the input shaft (pinion) is moved laterally.. and it only takes a little bit of wallow to unseat a shim.

another thing, though, is that (my observation) parts aren't made to be the quality they have been in the past.. that 9yo gimbel bearing is likely better quality than the new one... same w/ u joints.. there is a chance you replaced a heavily worn part(s), with a product that is out of balance.. 

TikiHut2

I'll be sure to post the cause when I solve the current mysterious illness. Makes me glad I only own a single engine boat.

Black_Diamond

Write a check for 1 or 2 outdrives, really just as painful..just different numbers.  lol

TikiHut2

Just talked to the drive guys at All American and he said it sounds like an early transition of a gear failure. He said if that's what it is that it'd be significantly less expensive to pull/ship/test/check tolerances and do a seal set ($1300 test/seals or 4200 with gears), than to have a gear failure under load that could (of course) be significantly more expensive ($6200). Price includes shipping with a 2week turn around. He also said that the B3 is usually good for well over 500hrs with reg maintenance where mine has been coddled and only has about 250hrs.

My local mechanic said if there's no metal on the drain plug and the oil looks good that I'm just being OCD. Normal noise in the drive is pretty typical. I may trailer it down and have him listen to mine running on a set of muffs.

I'm open to other insight since I just pulled this thing off last month. I'd just hate to lay out that much cash and effort if there's something I'm missing. Wish I had somebody down here I could use with an ear for this stuff. The upside is similar to my recent seawater pump trial, I can get it off pretty easily now.....and I still have my shop for a few more months. And of course it comes on the heels of a $5000 paycut at work 2wks ago. #:-S  Cmas will be unique if this little surprise from the Grinch of gear sets turns out poorly.

Thanks, Mike

212rowboat

Mike, get a powerful pin magnet.. the kind that telescope.. Lowe's has them for $5 or so for picking up bolts.. the face is about the diameter of a pencil.. drain and collect oil.. stick that magnet up in there and see if anything comes out with it.. it won't suspend as easily without the oil.. then (if clear), swipe that magnet through the oil a few times, wipe face on cardboard like its a marker and you're drawing about a two foot line.. use a flashlight from different angles and look for shine..

There is no way gears are wearing without leaving behind evidence...

Small, almost paste debris is certainly wear... It just may be time for them.. chunks that you can pick up between fingernails? Ruh Roh.. something is amiss.. I'm hoping you're out of alignment due to a slipped shim, which can be corrected.. and you may be able to do it yourself- it just takes ridiculous patience to do it.. take out, observe pattern, adjust, reinstall, remove, observe pattern, adjust, reinstall, remove, observe pattern, adjust, reinstall, remove, observe pattern......... Grrr..... Beer is not an option while doing R&P work....

TikiHut2

Off to the house and I'll give that magnet test a try tonight. Thanks

Black_Diamond

Re-doing a B-III on your own is a danger game.  There are all kinds of special tools, slider parts that can be rarely saved (any scratches/galling ruin them)...I watched mine being taken apart, just a can of worms if you are not trained to do it.  That from someone who likes to take things apart..and put back together   Al made mention about this on another thread too...use merc certified people.

At least with All American you get a 2 year warranty.  Ask about using the neosynthetic oil he recommends...

TikiHut2

Didn't have ANY intention of pulling the gear sets apart to tweak 'em with my non-existent drive train experience. The All American guys would/will be the guys to delve into that drives innards.

Tonight I pulled the bottom magnetic drain plug looking for metal debris or water and it was completely free of anything foreign. I then pulled the top magnetic vent plug and it was also clean. My neighbor with 30yrs experience as a Mercruiser mech for a major marina in town thinks I'm hearing normal gear lash/interaction. He said if there's no debris on the plugs, it shifts fine, and no grinding when I spin the props with the motor off then it's most likely just in my head.

Soooo....Maybe it's just me being at a sensitive spot for big bills and just OCD paranoid with my $6000 drive. I guess I'm going to run it and keep an ear/eye on it to see if it gets worse or pukes.

Wish me luck and in the mean time I'll go see a therapist..... or start saving for a replacement drive
 

Black_Diamond

Have a cold one, save the therapist $.  Always good to have an ear out for strange sounds, better safe than sorry.  I know when I pulled the drain plug when mine went bad, it was like pulling out chips from a lathe and grinding swarf.  But already knew it was toast.  I was very happy with All American..2 year warranty and driveable for me helped too. 

TikiHut2

I assume yours was/is a B-III. How old and how many hrs did yours have on it when it went south? Was there any warning or indication it was failing prior to the end? Hopefully it wasn't something you struck underway.

Taking your advice, I'll be seeing a local therapist who specializes in calming frayed nerves called Captain Morgan with his two assistants, a splash of coke and a twist of lime......

Black_Diamond

About 240 hours on my B-III's. It actually ran ok, started using oil..over 2 qts in the end just sitting in slip, looked like the Exxon Valdez when I backed out for pullout in the water. X_X it was the lower end that went bad, but everything was ruined by then. You could move the props ~3/8" back and forth. Amazing it even worked really. Never hit anything I know of...except my wallet!

TikiHut2

OK that's not reassuring but tell me. What year were they and were they making noise or was it just the oil slick that gave it away. Mine doesn't seem to be leaking oil but I swear it's oddly noisy.

What do you mean you could move the props 3/8"? When in gear? separate from each other? 3/8" doesn't strike me as much slop.

What was your eventual solution and approx cost per drive?

omg where's the Captn Morgan.....

Black_Diamond

The props moved axially 3/8"...which is huge!  The inner prop wore into the housing, lucky it was salvageable and I did not wreck the prop set too.  It's been 3 years now, so not so clear on the noise..but yes you could hear something (I just didn't know what at the time)..I'm always listening now  Drives were 2003, I figured I blew an oil seal but at haul out I saw a nice shiny ring on the case from the prop digging in and I knew I was in trouble.  I pulled both drives figuring if one was bad, so the other might and I was right.  not as bad but on its way.  I think I was in for 8-9k when all said and done, both drives reworked, did some upgrades they recommended, new paint job on both and the better oil.  Never got a real reason why other than it looked like the drive service I was paying for was not quite being done either (drive oil changes).  The year before a coupler died on the same side too and they said it was from being out of alignment..never mind I paid to have the drives pulled and serviced annually (including alignment).  Needless to say I now do a lot more on my own so at least I know it was done!

I invented this little item to flush out the reservoir and tube  worked like a charm.  Both lines were filled with chunks and thickened oil.  It lets you pull in or out oil/cleaner of the tube.  Just bolts on when you take the drive off and opens the push button valve.

Michael T

Geez BD, I smell a patent coming! Nice! MT

TikiHut2

Yeouch. 3/8" axially is unbelievable that they hadn't come completely unglued. I was thinking something like 3/8" of a turn on the prop for slop....

Thanks for adding your painful details. I hope mine is merely in my head but that is almost exactly how old and how many hours I have. No debris in the oil at this point and since we trailer I'd know immediately if it was leaking. Keeping my fingers crossed.

Interesting tool too. Thanks, Mike