How does the transmission work?

rasbury

I have an issue and a thread going on a bravo III/350 MPI. I have had some sort of failure that most likely is a coupler. I brought the boat home last night and I am going to start doing a little look over before I take it to a shop. I have little to no experience working on motors and such, handy at best with general maintenance. Anyway, while I have read a lot I'm not convinced on the coupler and in all the responses to my posting, no mention of all as to how the transmission fits into the drive line equation.  I did find it in an engine manual.

When my failure happened, I was low speed and heard this awful metal on metal turning/scouring noise for two seconds. I quickly shut the motor off. I restarted (why I did that I'm not to sure) it cranked but no response when shifting. I also don';t recall that the engine RPM responded to moving the shifter forward and back but I was pretty freaked out. So, shut it off and anchored waiting for sea tow.  So, just brought it home and will look at all the cables and hook ups to those as well as inspect to see if the drive shaft is turning by turning the props by hand. I know the coupler is mounted to the flywheel, input shaft from the out drive goes into the coupler- where does the transmission come into play?

pault1216

I think there is only a clutch mechanism in the lower unit for forward-neutral-reverse and that is all. If the cables are all functional then my guess is coupler. The mechanic noted mine was almost shot during routine maintenance when he pulled the drive and noted the splines were damaged on the coupler. Good luck. I am sure an expert will chime in after morning coffee!   -Paul

rasbury

Coupler is the main suspect, on my way out to take a look. There is a transmission of some sort, even shows where to check the fluid...will go out and take a look.

Handymans342

There is no transmission. You have outdrives. Transmissions are only on shaft boats, understand?

rasbury

Ah,thanks @Handymans342 ..looked before and could not find anything!

Handymans342

I wish I had a tranny so I could spin my prop faster without any more motor RPM

rasbury

Yep, Iget that...

212rowboat

there is no transmission in the sense you're thinking- there is a simple coupler, which bolts to the flex plate and has a splined coupler in the center the shafts slip into... the rubber of the coupler is the connect to the engine.... 

now what there is, that is actually a transmission- is the outdrive.. that makes the prop the differential- and you're just gonna have to make do without tires... the upper turns the torque 90*, and the lower turns it 90* again... the magic of reduction and sun/planet gears happens there- which is witchcraft and black arts which I recommend you leave to those who've already lost their soul.  

i think i mentioned before about a ujoint yoke possibly snapping, and that may still be the case.... that could happen if there was crazy angles requested of it and then stiff torque applied- it literally takes the slack out of the joint, makes some more, and then BANG it snaps... I may or may not have encountered this phenom before, but not in this application... 

Black_Diamond

If the u-joint snapped, it would be flailing around and make a not so nice noise. The splines shearing on the coupler/shaft would make a nasty metal to metal grinding noise until it wore bad enough it was just free spinning. 

Either way, looking down with a flashlight at the coupler, look for shredded rubber, metal flakes etc. have someone spin the prop by hand with the drive in gear...should not turn. If it does see if the shaft to the coupler spins or not. If not, the issue is in the drive. If so: coupler/shaft splines. 

There is a HD coupler to upgrade what you have. Worth the few dollars. 

rasbury

So, I took it ba k do where I store if and they also does work- have a friend that highly recommended him. He advises there is another coupler of sorts between the lower and upper part of the drive that has failed. So, I have asked him to go ahead and pull it and to see what the issue is. Once that happens I will update the findings. I think it a plus that the motor does not need to come out?

Black_Diamond

Yes, there is a vertical shaft connecting the upper to the lower. I think you can upgrade that shaft to from the one in the BravoIII-X too. 

pault1216

Motor needs to come out if it is the coupler. I think he is referring to the u-joints which would be easier and cheaper to replace.  -Paul

rasbury

Sounds like my issue is lower unit. I'm just not sure I would not trade a coupler problem for a bravo lll problem as the couple would be pretty straight forward a repair...going into that lower unit bothers me foe sure!

Handymans342

Try to get us some pictures

212rowboat

there is witchcraft and sorcery on the other side of that casing.... enter with caution.  in all seriousness, it can be done- we have the technology- but would you rather not allow someone else, who does many of these a year, to do it?  If you get it wrong- shim incorrectly, or the backlash is off- pattern is wrong- you'll be right back in there.  from what I understand about BIII's this is easy to do.... from what I understand about B2's and Alphas, it happens...... 

yeah, a coupler is simple... drop drive, pull engine = an hour... swap coupler sink engine = another hour (time is for back yard mechanic's, the whiz-bang mechanic here says he can have a boat fresh out of the water with the engine hanging on a hook in twenty minutes, and I believe him)- alignment and reinstall of outdrives half an hour... it's literally a late afternoon job.  

best of luck, sir- but as a parting comment/advice:  I'd locate a specialist and let them open that case- their magic is powerful too, and capable of containing the sorcery planted there by merc.  

rasbury

I hopefully have found someone that knows what they are doing. I spent many years working around tool and die people and machined parts. This is way over my head.

Handymans342

Any word yet Ras?

earl1z19

Had a similar issue last year with my bravo 3. Was at about 4000 rpm and heard a loud thump and the starboard motor shut off. The engine would crank over after that and actually started but it sounded awful. Ruined the top half of the lower unit but the coupler was good. Replaced the whole drive because metal shavings were spread throughout. Hope yours inst that bad caus it aint cheap..

Handymans342

What was the bill Earl?

earl1z19

Ended up being 2 drives in all for a whopping $11558.95. Its a story that involves a bad maintenance procedure from the dealer that i bought the boat from that effected both drives. The dealer covered the repairs though!

earl1z19

BTW, I had the repairs done at a top notch 3rd party business just to be sure it was done correctly

Dream_Inn

I'd been in the same place as earl...twice (once for each outdrive).  Definitely best to replace the entire unit, then you know what you have and it takes longer (usually overnight) to get the drive than it does to replace.

earl1z19

It was literally overnight. At least you know that the weakest link on your boat is as strong as its ever going to get when it goes back in the water!

Black_Diamond

Been there. 2x B-3 were almost $9k. Brutal. 

Handymans342

Dream why didnt you replace with B3s?  Just wondering

rasbury

Have to quit following this until I hear...he thought he'd get it pulled this week..

212rowboat

i can't answer for DI, but.... those stupid yoke's/transom plates are STOOPID expensive, and there isn't that much to them... you'd have to fill some holes and drill some new ones, too... that is spooky, to me, at least... 

Handymans342

The inner plate was $100 I think 

Dream_Inn

Handy, one of the reasons I didn't replace with B-3 was each drive went at different times.  So, when I replaced the first, I had no idea I'd be replacing the other a year & a half later.  Second reason, I'm very happy with the performance of the B-2 drives.  Third is cost.  I'd have to not only pay for drives, but 4 new props.

@alswagg, are you saying you can buy a new B-3 for 3k?  Is this a brand new one?  Whole drive, lower and upper?

@black_diamond, 9k total for both drives replaced? 

Why am I seeing a 5-5331600TP Bravo II DRV 2.00 online for at least 6-8k??  Please send me a link for a brand new OEM Bravo 2 or 3 drive for under $6k?

ok, maybe I am paying too stinking much around here!  For one B-2 drive last year, I spent almost $7000.  Also had everything else in there replaced since drive was off (bellows, gimble brg).  Also included haul-out, blocking, installation labor and initial labor tearing old one apart to diagnose.

Handymans342

Well on the SEI website its 5900 for a B2 but that is a reman

rasbury

He has not pulled it yet, was going to do it sometime this week but have not heard...

Handymans342

What? You could have towed it up to Als shop by now

Dream_Inn

Ok, BD, understood just a rebuild of everything.  I ended up completely replacing mine with brand new ones, just connect up. 

Sorry Ras, don't mean to make you feel like that is going to happen to you.  At least you only have one engine

212rowboat

Black_Diamond said:

Winterizing....scary word already. 

say it ain't so!!! I'm just getting my gal dialed in!!! (but I can cruise into November, here)...  

randy56

Gee Al how many boats are you planning to winterize? I did see a lot of them up there.

rasbury

@212rowboat- waiting to hear the news. The drive may be fine, not so sure anymore since I felt what would appear to be coupler material at the drain so we will see when he pulls it...

Black_Diamond

$9k for rebuliding both B-III drives. Basically total replacement of the guts.