Replacing bravo 3 out drive.

Oct 14, 2018
57
Boat Info
260 Sundancer 2002, 5Kw Westerbeke Genny,
5.0mpi/new B3 in 2023, Simrad gps plotter/sounder.
Engines
Merc 5.0 MPI, w Bravo III Drive
A month ago or so while towing grandkids around for an hour or so I noticed a slight change in vibration/ noise while in gear up at 2500 + rpms, this along with an oil in bilge issue, which I did solve( seperate thread ) has kept our boat close to our marina. Before I haul her out, I ran in neutral at various rpms, turning wheel lock to lock, definitely a jumping, bumping
Marraca sound when at rpms above 1k , progressively worsening through 3k rpm while in a full port or starboard steering position. Almost zero rumble or vibration at idle or below 1k rpm. This was all in nuters, Local marina mechanic says gimble bearing for Sure...so I haul her out, our vacation trip is up coming.
We managed a week's trip to the BC coast but we didn't haul our boat down to coast.
We stayed aboard my father's 58ft Navigator in the beautiful Desolation Sound area. You know the kind of trip, days of 100 prawn sets, 12 Dungeness crab in each trap, oh did I mention buckets of fresh oysters picked off the shore, a few ling cod, saw some sea otters..gotta love it...bit of Coastal heaven.

Once home after work days I have been figuring out how I can solve the rumble/ vibration noticed previously. Going to teach myself how to Replace the gimble bearing, mechanics I talk with, ( I am a DYS kinda guy) they suggest checking the upper and lower leg while I'm out too..so I do.
I had taken boat out of her slip and put onto trailer while away on the west coast trip so I pulled props to check output prop shafts.
Notice Quite a bit of chatter when spinning prop shafts by hand, so I dropped an ounce of gear oil, found metal fillings. Drained entire leg gear oil...definitely metal..drain magnet was covered as was a separate magnet I dropped into the oil bucket... next step..curse..next step.... get quote on outdrive from mechanic merc dealer, lower unit $6700.00, complete unit $10890.00 plus taxes and 100 to 400 in misc parts depending on how my bellows, shift boot, shift cable etc then labour.. 2- 3 hrs estimated ... no one rebuilds they say.. it's a 17 yr old drive they say....next step.. curse some more..
Then I start looking for reman unit in same drive ratio that is in 150 km radius from home so I can go pick it up.
Finally a bit of luck, 100 Kim away, freshly rebuilt, complete upper and lower unit done with OEM parts in the correct gear ratio, with a 10 month warranty. They will give me 1k off for my old core..so $4500 vs $10890
Local shop mechanic is going to arms length assist me and lend me the specialty tools I will need to do it right....by Sept 10th if all goes as planned I should be ready to relaunch her and get a month or so of boating enjoyment in...will keep you posted..wish me luck.
 
Those B3's run hot as hell, they can easily turn the oil black in a 100 hours. Drive shower and frequent oil changes will keep them alive.
 
Those B3's run hot as hell, they can easily turn the oil black in a 100 hours. Drive shower and frequent oil changes will keep them alive.
My oil would be black when I changed it at the end of the season. I added a drive shower. Now the oil looks like new when I change it out.
 
I wouldn't be too quick to run out and get a new drive just yet:

  • A change in the sound or even a knocking sound is normal when when you turn the wheel hard over. The sound of the u-joints spinning changes in frequency as they are turned in any direction. It's not a good idea to turn hard over at an speed above idle.
  • Bad gimbal bearings make a growling sound that will increase with RPM - it's just like a bad wheel bearing in a car. And unless they have been wet or run totally dry they can last the life of the engine. My 20yr old boat still has the original gimbal bearing.
  • Some amount of metal is normal in the gear oil - looks like a "fuzz" on the magnetic plug. Sounds like you might have a little more than normal though.
  • Turning the props or running the engine on muffs produces a lot of noice that you don't hear when the boat is in the water. Outdrives are noisy things.

You could very well have a problem, but BIII issues usually start with shifting problems - ie the cone clutch going bad. The gears in those things are beefy, they don't just break unless there is some other issue - water in the gearlube etc.

If it were me, I would check the gimbal bearing and replace it if needed, change the gear lube and run it another 10-20hrs and check it again. Then asses if you really have a problem. If the drive is going south, you don't have anything to loose.
 
Last edited:
I agree with BillK

Had issues with ujoints several years ago, thought the whole drive was bad.....
 
I’m Curious.
How many hours on your 260?
Bought boat at 680 hrs last September, all checked out ok currently 725 hrs on her.
 
Those B3's run hot as hell, they can easily turn the oil black in a 100 hours. Drive shower and frequent oil changes will keep them alive.
Drive shower? I'll have to Google/ YouTube that one, wouldn't that be more for a racing drive, high rpm systems.
 
Drive shower? I'll have to Google/ YouTube that one, wouldn't that be more for a racing drive, high rpm systems.
Not at all, what color is your oil at the end of the season ? If it's not the color of fresh oil it's running hot.

I mention this because your drive is failing. There should be no metal in your oil or fuzz on the magnet if you properly maintain it and the props should turn with no noise in neutral.
 
Up date to the Bravo III saga, I pulled the drive late last week to replace the Gimble bearing with a new one, local merc service shop sold me an OEM non greasable unit, said thats all they sell now. Once drive unbolted and removed I found out where the 900 ml of Gear oil I had added since May splash day ( 30 hrs running )..Ive never saw any oil in water around boat during that time. Gear oil was all in the drive shaft bellows and poured out on drive removal, the upper drive drive shaft seal and bearing have failed, pieces migrated in oil down into lower unit and scored the lower bearings ( chatter while spinning in neutral) ...totally toasted...rough day finding all that. With the upper and lower unit off the boat, I checked out all bellow water rubber parts, they are in excellent shape, I know the Po had said they redid the steering pins 3 years ago so that all looked as expected.. I then drained all the gear oil from my drive again,( I had done this a week ago following BillK s advice and added 5 hours of low and mid throttle running time , the oil was still very dark ) found loads of metal flakes attached to both upper and lower drain /fill magnetic plugs. the drive shaft universals where all smooth as silk on removal. I replaced my old greasable gimble unit and inner grease seal with the new ones and plugged the grease passage off with the supplied plug, the old bearing is also smooth as silk so it definitely was NOT causing any additional rear drive noise. ( may have wasted the $$ on that one, but at least I KNOW its new)
Heading to shop tomorrow, to pickup a newer 2006 BIII upper and lower reman unit ..then the install and back into the lake for what I hope is 6-8 more weeks of use before the winterization begins. Shop is willing to give me 10 months warrenty on the reman drive, so we will run the bejesus out of it till warrenty expires and then get many years use going forward, I hope... Also I am Seriously looking into installing a drive shower onto the reman drive unit.
 
Well, at least you now know you didn't jump the gun, you have the evidence that it was at the end of the road. Just not worth putting any $$ into it and you couldn't continue running it with it spewing oil out of the upper seals. Look at it this way - it was 18yrs old, it really didn't owe you anything - we would like things to last forever, but they just don't. Plus, the newer units have additional anodes, so you did get somewhat of an upgrade. Swallow the pill and go boating!
 
Finally got the rebuilt upper and lower unit for the B3 outdrive last week, one month after expected due to bo parts..total price after core exchange was $4200 cdn rebuilder is warranty whole unit for 12 months since the next 6 months she will be sleeping in winter storage. Did the full main engine winterization on my own plus all systems done...only hiccup and it is a big one..
I learned to NEVER USE HOSE WATER PRESSURE to flush generator.. last year I was still in the marina and warmed it up just by starting it , then changed oil, filter plugs then disconnected raw water feed hose and plumbed in a 3/4 inch line feeding -100 merc anti freeze... Bob's your uncle..done. flashed right up this spring.
This year with the late arrival and installation of rebuilt out drive I boat was not in water but in storage yard on trailer so I set up the genny same systtem as I have used to flush & warmup main engine..big no no.. especially with water hose turned on BEFORE GENNY ACTUALLY FIRED UP.. instantly hydolocked cylinders..#$%€..
Motor never started ..but was cranking when lock occured..I was quick enough to realize what happened so pulled plugs right away..drained water out of cylinders by cranking over on starter, then with shop vac, drained oil 2 times, new filter 2 times , then set up a gravity flow feed system into raw water pump which allowed me to start engine and warm genny up. It started and ran with a few sputters first. Shut down and drained oil and replaced filter again, ran again, drained again..
Finally ran for 30 minutes, drained and replaced oil and filter again. Then ran 20 ltrs of antifreeze through raw water feed while warm and running. While it was running after all oil flushes and filter changes there was no noticable change in noise or vibration.. so I think I dodged a bullet..
I guess I will know more if any internal damage after a few hours running next spring.. would be sad If I have buggered it ..it only has 405 hrs and purred like a kitten..fingers crossed. I Will be wondering all winter..but Lesson learned..
On top of all this thieves broke into a few boat, including mine in the secure ??? Storage yard stealing 3k worth of personal stuff from my boat.
Insurance will cover to replacement values less 250
Deductable...
 
Continuing saga of my B3 outdrive issues, finally launched on May 15th. Everything at marina held up due to covid19 this spring. I had towed boat home late april from winter storage to recomision leading to may splash day, did full hull scrub, wax polish and bottom repaint.
Started Maine engine with muffs in yard on trailer, this was the first time it ran with rebuilt upper and reman lower drive unit. Drive trim set at 3/4 down.
Engine fired right up, sounded normal, let her warm up for 10 min or so then shifted into forward....smooth as silk, sounded good, shifted into nuteral.. then into reverse...All good. No unusual sounds, so I'm really happy, the install of the upper and lower unit was a first for me.
Next step, launch,
May 15th, engine fires right up while backed into lake but still on trailer. Engine trimmed down 3/4 way. Warm up for 5 then into reverse and back off trailer, maneuvering over to my slip and I trim down further on drive, right away there is a rattle that starts, coincides with rpm, changes volume as I turn helm port or starboard from center. I trim up and it disappears as I get to 1/2 trim on gauge.
I'm wondering if this is caused by me maybe not getting the new gimble bearing and engine aligned properly, I had used the merc alignment tool I rented from marina shop.
The tool showed splines evenly scored in grease and it looked centered in driveshaft tunnel..so I'm stumped.
Other thing I think it could be is worn u joints. The upper unit was a reman unit, I remember that the ujoints seemed smooth and not sloppy at all before I installed unit last fall..
Any thoughts or suggestions for possibility causes would help ...I'm thinking I will have to remove the drive...again...even at the old drives worst it didn't make this new rattle sound..
 
I forgot to say, I have run motor for 1 hour since my launch. At different throttle positions in gear up to full throttle cruising with trim set at 1/ 2 on gauge while maneuvering boat at different helm positions and there is no rattle...but any trim position below 1/2 on gauge and even with a centered helm causes the rattle..much worse at trim full down and hard to port or to starboard helm positions.
 
Gimbal bearing and then alignment is in your near future
I think he states he replaced bearing and used tool to align.

Fwiw - I had a guy work on my b3 trying to address some knocking noises - said he could fix any b3. A year later it blew up - so I bit the bullet and bought a new drive. No more problems. Hope you have better luck.
 
I think he states he replaced bearing and used tool to align.

Fwiw - I had a guy work on my b3 trying to address some knocking noises - said he could fix any b3. A year later it blew up - so I bit the bullet and bought a new drive. No more problems. Hope you have better luck.
reread post 14 said he didn't get a new gimbal bearing
 
Is it possible there is a trim limit insert and it is installed in the wrong position? Not sure if it can cause an issue like yours but have seen it referred to in the B2 manual and is reversed for B3 applications to limit trim in.
Proper engine alignment is important.
 

Forum statistics

Threads
112,872
Messages
1,420,835
Members
60,871
Latest member
cbrcassio
Back
Top