B.S or not

[Thalasso]

Buddy just had his Bravo111 worked on and the shop said they replaced a pump (or something to that effect) that keeps the drive from coming up when backing down.
Never heard of this. Is there such a thing?
Knew it used to be an issue with outboards but never heard of this in a i/o

 

[Bt Doctur]

The newer mercruiser trim pumps have internal valves to prevent the drive from raising up while in reverse

 

[Thalasso]

The newer mercruiser trim pumps have internal valves to prevent the drive from raising up while in reverse

This is a 05. That's what i would think that it's in the trim and not internal to the drive

 

[Fun Times]

Can you get ahold of the parts invoice for a part number/description?

There have been a few recent postings lately on (other forums) suggesting that the Bravo drives are floating up....A few mentioned while in reverse gear while one said it happens while getting up on plane but I thought he said he had a left hand prop.

The valves inside the pump hold the drive down unless there is an impact.

Drive Unit Impact Protection:
The Power Trim hydraulic system is designed to provide impact protection for drive unit. If a submerged object is struck while boat is moving forward, the hydraulic system will cushion the kickup of drive
unit as it clears the object, reducing damage to unit. After drive unit
has cleared object, the hydraulic system allows drive unit to return
to original operating position, preventing loss of steering control and
engine overspeed.
Use extreme caution when operating in shallow water or where underwater objects are known to be present. Use extreme care to prevent striking submerged object while operating in REVERSE. No im-
pact protection is provided in REVERSE.
If drive unit should strike a submerged object, stop engine as soon
as possible and inspect drive unit for damage. If damage is present
or suspected, boat should be taken to an Authorized MerCruiser
Dealer for thorough inspection and necessary repair. Operating a
damaged drive unit could cause additional damage to other parts of
drive unit, or could affect control of boat. If continued running is necessary, do so at greatly reduced speeds.
IMPORTANT: Impact protection system cannot be designed to
ensure total protection from impact damage under all conditions.

 

[thumpar]

Was there an issue with the drive going up in reverse? The only pump that has to do with that would be the trim pump. I would figure out what they replaced.

 

[Thalasso]

Was there an issue with the drive going up in reverse? The only pump that has to do with that would be the trim pump. I would figure out what they replaced.

I asked to see the invoice as i didn't think there was anything internal as i understood there was.

 

[Thalasso]

Can you get ahold of the parts invoice for a part number/description?

There have been a few recent postings lately on (other forums) suggesting that the Bravo drives are floating up....A few mentioned while in reverse gear while one said it happens while getting up on plane but I thought he said he had a left hand prop.

The valves inside the pump hold the drive down unless there is an impact.

Even if it was left hand while going forward it wouldn't come up. My guess is my friend misunderstood him but i am going to look at the invoice

 

[Fun Times]

While we're waiting on the invoice, figured I'd just pass on the info from the other 2 topics I recalled reading. I was mistaken about one of them having a left hand prop.. I may have mixed up the posters port side drive as being left hand prop or possibly just "assumed" he had a left hand prop which like you mentioned shouldn't have much affect on the situation.

The first two quotes is the one I read first but there is no solution mentioned while the last quote below turned out to be an internal issue with the cylinder rams on an older Alpha type drive.

Lower unit seems to be drifting up under power:.
I have a 1996 32ft Baja with twin 454s with Bravo drives. When I hit the throttle out of the hole, my port side lower unit throws a rooster tail and reves motor. Does not do it all of the time. I stop and make sure lower unit is down, which it always is, hit the trim button down again and most of the time that corrects the problem. Trim fluid is full. I'm thinking that either my trim rams could be weak, which they don't seem to be, or that my trim pump valves could be pushing fluid back into pump while under power. Any advise would be appreciated. Thank you

What baffles me is when I look at lower unit, it is in the down position. If the trim was moving up , the lower unit should also stay up when I stop. Another marine tech is the one that told me about the seals in the pump. He stated that although the prop is pushing a lot of water (as you stated) but he said there is a lot of pressure on the lower unit moving forward? Also on the rod that ties the lower units together, the rod end got bent on the lower unit in question???

http://www.riverdavesplace.com/forums/showthread.php?148491-Trim-pump-question&highlight=Trim+pump

Turned out to be more then just a seal kit. The internals had some issues with the sleeves and the little Pistons which was causing internal leaks. We made sure that the pump was matched up correctly to these trim cylinders and I mentioned how I could lift the drive with my hand and he said ya it was definitely the trim cylinders. All said and done he charged me 287 which seemed a little pricey for what it was worth but oh well if it fixes the problem boats good to go.