Bravo 3 Power trim unit fluid - recommendation & question

[Wired2Cruze]

Hello all,

Got my boat ready for splash yesterday, and noticed the power trim reservoir was empty.
I usually keep an eye on it during boating season, and refill when necessary, if the audible alarm doesn't let me know first.

I've been using Hi-performance gear oil (the kind you use in the outdrive, recommended by P.O.), and used my last to refill the reservoir.
So I'm not sure what happened over winter, but I plan on asking the dealer who winterized the engine (includes "Check all fluid levels"). I'm hoping they just forgot to refill, but I'm not sure why they would drain the system in the first place, even when they were changing the gear oil in the outdrive.


I searched thru this forum on the subject, and found this response from 2009:

A couple FYI's:
-- There should be ATF in the steering pump and straight 30-weight oil in the trim pump.

-- Merc's brand Trim and Steering fluid will mix with any fluid already in there. It can also be used completely by itself, but it gets expensive for the application.



So, I have some questions.

1. Is it customary to drain & refill the trim pump oil when draining/refilling the outdrive oil?
2. What fluid should I be using in the trim pump?
3. If is should be using something other than gear oil, is it ok to just add it, or should I drain & refill with the correct stuff?


Thanks for any responses

 

[Bt Doctur]

So, I have some questions.

1. Is it customary to drain & refill the trim pump oil when draining/refilling the outdrive oil?
2. What fluid should I be using in the trim pump?
3. If is should be using something other than gear oil, is it ok to just add it, or should I drain & refill with the correct stuff?

1 no, they are 2 different systems
2 10W-30, 10W-40
3 the monitor bottle takes the gear oil. it is usually changed when the drive oil is changed

 

[Bt Doctur]

http://www.b,o,a,t,f,i,x.com/merc/Techbk/94/94hsco.pdf this link should explain everything, you need to remove the comma`s then copy and paste the link

 

[Lazy Daze]

Right, usually just straight 30 in the trim pump - not sure why that system would even be touched during winterization. You need to check into that - if they didn't touch it, then there's a leak. If you put gear oil in the trim system, then you need to have someone flush the system for you.

BUT... something has me wondering... you mentioned that you "keep an eye" on it and fill when necessary. Sounds like you have a known leak - it shouldn't be changing levels, other than with the normal "up/down" of the drive. The second thing is that you talked about an "alarm" - there is no alarm associated with the trim system. That alarm is with the gear oil system -- are you sure you have your terminology correct and/or are talking about the correct system?

 

[Wired2Cruze]

BTDoctur,

Appreciate the link, but it just gives me a pdf of the table of contents to the manual, no actual contents, nor links to the rest.


Dennis,

It's very likely I'm mixing terminology here, and perhaps confusing my recollections of prior problem-solving.

So I'll start over.

You're right, the audible alarm system is for the outdrive oil. When it goes off (usually after punching through rough seas for a while) I refill the little reservoir with hi-perf gear oil, and that resolves the alarm.

When I put in yesterday, the trim pump worked, allowing ,me to lower the drive.
I heard the audible alarm for a few seconds, then it went off. I figured that's just the gear oil being distributed through the outdrive, after winter layup.

When I tried raising it at the dock, the pump didn't run, I just heard clicking (kind of like the sound a bad bendix spring in a starter makes).
Both the trim switch & the trailer button gave the same results. I figured both solenoids were bad.

That reservoir was empty last nite after running for awhile, but no audible alarm sounded after that 1st few seconds.

BUT - After I refilled the reservoir using the gear oil, the trim pump issue was resolved.
It sounds like this may be coincidence, rather than related actions.

When I turn the key to acc, I get an audible alarm after a few seconds, but I know the alarm sounds for 3 different events
Engine water temp, oil pressure, & stern drive oil.

I'm now wondering whether the sensor for low outdrive oil to the audible alarm is not working correctly; it seems to me I should have heard it if the reservoir was completely drained.
Is there a way to test for this?

And I'm wondering if the solenoids just can work intermittently like that, if they're near the total failure point.

 

[Lazy Daze]

Just to be clear, the trim pump was never empty? It is "typically" normal practice to change the gear oil during winterization, but not the trim fluid.

Yes, solenoids can be flaky... Intermittently working/not working.

Test the gear lube float switch two ways (both with the engine running):

1- manually push the float all the way down
2- disconnect both bullet connectors and short them to each other

Both ways should kick the alarm on.

FYI: the alarm initially sounds when the key is put to the run position because the engine is not running, therefore zero oil psi.

 

[Bt Doctur]

dosent matter, you already know the drive is leaking oil and need to be hauled before you run out of oil
this is power trim

this is outdrive oil

 

[Wired2Cruze]

I verified the locations of both reservoirs yesterday. The Power trim reservoir (red 12v & blue & green wires) was at an acceptable level, I have never had to refill it.
So the outdrive reservoir was empty after running on Sunday, I will need to monitor that. I won't be able to perform the audible alarm tests for a few weeks (vacation plans).
I have a bottle of SAE 10W30 for the engine oil, and it's good to know I can use it for the trim pump reservoir if needed (haven't had to top it off in the 4 yrs I've owned the boat).

Thank you much Lazy Daze & Boatdoctur for your help!

 

[Lazy Daze]

OK, so you need to verify if the bottle went down simply from air bubbles in the system after a gear oil change or if there was never gear oil put back in or if there is a leak. While it's normal to get some air bubbles, they should work themselves out within a short period of running and the level should eventually stabilize. Leaking is not good at best, and very bad at worst. Having no gear oil (or just the tiny little bit from filling the bottle) and running the boat is just plain bad.

 

[Bt Doctur]

What amount of service in those 4 years was given to the outdrives?
not to mention destroying a perfectly good drive. and what they cost Part Number: 1589-863836R50
Description: REMAN D-HSG BRAVO BI BII BII (Mercury/Mercruiser)
Price: $ 4638.50
Retail Price: $ 5018.71
Weight: 73.0

 

[dan313]

I have the same issue with my drive. I had the drive pressure tested and it check out ok. I used the boat yesterday and the reservoir was full when I left the dock. When I returned the oil level was down. I have lived with this for the last 4 years. I have researched this and some say it is normal for the drive to blow oil out of the seals when underway. Dennis if you have a fix for this please let me know.

Thanks,
Lenny