noise bravo three upper end

A

aerobat77

Active Member
Aug 12, 2014
815
germany
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Boatless
hallo gents !

i have somekind of a rattling / rumbling noise on my upper end of the drive with engine running in idle and no gear engaged .

i have heard it also last season and told my mechanic who pulled the drive and verificated for sure during winter inspection that :

- gimbal is in perfect shape
-u joints have zero play
-no metal debris on the oil screw
-no water in gearoil
-props spin free without any noise by hand

he told me that i should take a pill against paranoia and just go boating what i did . i just finished summer holiday on the sea and heared the rattling idling at the dock , engaging gear will cut this noise immediately . the drive shifts smooth and performs well so i did not care .

after hauling the boat and running on muffs to get the saltwater out the block i now realized the rattling sounds really not good and definitly comes from the top of the drive and i do not believe its normal !!

two years ago i had the cone clutch and shift cables replaced by a mercruiser certified dealer , the drive has 280 hours , boat is a 2006 240 sundancer with a 5.0 mpi / bravo III .

what is your opinion , i fear big money to spend soon and also a drive failure being underway.

thanks for any inputs !
 
If it doesn't sound right to you, get a 2nd or even 3rd opinion from other mechanics. If you run it until the bad parts fail, it is likely to cost much more to fix.
 
that are my thoughts - not to run it until fail . on the other hand mechanic tells me ( until now by phone ) nothing is bad when i do not have metal debris on the oilscrew , might be some play on the cone clutch .

a question to b3 owners : your drives run free of any mechanical noise hooked up on muffs in neutral ?
 
They should make no noise. I just did a repair on a drive that was also making a clunking in neutral. It was the pinion assembly that was loosening up. It ground up the beveled washer and the pinion nut was loose. New washer, set the preload and all was good.
 
thanks scoflaw ! how much worktime did you need for this repair ? i looked at the repair manual and it seems to be not that hard to do
 
Real simple. You'll need that special spanner tool to get the big retaining ring off, then the assembly just pulls out. My problem was obvious, so I didn't press the big pair of bearings off the pinion. Nut gets torqued to 200#'s
 
ok ! i have some fair knowledge on taking hand on mercruiser and volvo engines but never had hands on a b3 beyond pulling the drive so please excuse should i give a stupid question :

you are talking the nut of the pinion gear on the u joint assembly , correct ?

am i right that after removing the retaining ring the u joint assembly will come off without first removing the clutch assembly , so no need to open the drive from the top ?

an hour ago i had a friend who is a retired volvo penta mechanic and we ran the boat at the muffs . we actually again removed the oil screw to check for debris but there is zero debris . oil also perfectly clean .

putting the drive in gear with engine off there is maybe half an inch of play and you hear a metallic clunk from the clutch area moving the prop against the gear and back .

but he is not sure if thats normal or not .

he said he is a volvo guy so no experience on a bravo and how it should sound but he agrees it sounds a little strange - but says if i would have some major problems on a bearing or the pinion the WOULD BE FOR SURE metal debris .

what is your opinion ?
 
aerobat77 said:
ok ! i have some fair knowledge on taking hand on mercruiser and volvo engines but never had hands on a b3 beyond pulling the drive so please excuse should i give a stupid question :

you are talking the nut of the pinion gear on the u joint assembly , correct ?

am i right that after removing the retaining ring the u joint assembly will come off without first removing the clutch assembly , so no need to open the drive from the top ?

an hour ago i had a friend who is a retired volvo penta mechanic and we ran the boat at the muffs . we actually again removed the oil screw to check for debris but there is zero debris . oil also perfectly clean .

putting the drive in gear with engine off there is maybe half an inch of play and you hear a metallic clunk from the clutch area moving the prop against the gear and back .

but he is not sure if thats normal or not .

he said he is a volvo guy so no experience on a bravo and how it should sound but he agrees it sounds a little strange - but says if i would have some major problems on a bearing or the pinion the WOULD BE FOR SURE metal debris .

what is your opinion ?
Click to expand...
no metal made it to the magnet on mine. Should not clunk. The pinion assembly pulls straight out without removing the 2 covers. I would pull both covers and have a look at the fork and the clutch. Basic hand tools are all you need. I would flip the clutch over while you are there, there will be more wear on the forward clutch
 
please let me puck up my old thread .

i finished the 2017 season with the described problem but now i removed the drive and the driveshaft with u joints and pinion assembly . the gears look brandnew . no wear .

i have set preload on the pinion and nor reassemble the drive . what i found : when turning the driveshaft by hand forth and back ( drive is in neutral ) i see a little bit of play / gearlash . is this normal ?

best regards
 
What did you do for a repair ? Don't have my manual here. Every gear set should have some backlash. Question is how much do you have ?
 
well , up for now i found the pinion preload was to loose . now i,m wandering if that was my only problem . i will reassemble and run it on the muffs to hear if the rattling is gone or not
 
Did you check the tension between the 2 pressed on bearings that are on the pinion shaft ? They should have a slight drag when you rotate them in opposite directions. The bearing cups shouldn't rock
 
honestly not, i just have set the preload to specs according to the manual . it was a little loose . all bearings and gears are in very great shape , next days i will try running on muffs and splash the boat . fingers crossed my noise will go away.
 
Except those 2 big bearings you can't see cause they're covered with the cups, but oh well... good luck
 
spinning the pinion inside the bearings gave absolutely no noise or roughness or tight spots. so i hope the bearings are ok . i,m not sure now if my gearlash in the upper gears is ok . i guess 1/3 inch of play there when turning by hand .

btw ... torquing the retainer nut to 200 gives you the impression you will break the entire housing every second ... scary
 
1/3 sounds like a lot. Does Merc give that spec.? With a car ring and pinion .010" is a good backlash.
 
Does the rattling go away or change when moving trim or steering?
 
hey gents ! after adjusting the preload on the piniongear and torquing the retaining nut to specs the rattling went away , dont ask me why .

on dissasembly i noticed two things :

the preload was to loose a little bit
i had to get 200 lb in torque on the nut significantly more force than was needed to loose it . i guess it was torqued to less than 200 previously .

hopefully no more problems !
 
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