Jrock

This is a bravo 1 single application.

I've been fighting with this for over a month. Need advise from the OSO.

The problem is, the drive trim operates normal until I reach 4000 rpm. After that, the trim appears not to work. Can't get the boat on it's pad. I can't hear if the pump is working,( very loud exhaust ). I can set the trim at any position below 4000 rpm's, put the thottle to the boards and she'll ride on the pad.

I have replaced the trim pump assembly, both trim cylinders, and tried reversing the hydraulic lines at the pump.

No change! Any ideas? PLEASE HELP.

Turbojack

Have you tried using the trailer button instead of the trim button? The trim button is made to only let the drive only go so far up. Could it be that this trim wire get pinched somehow? Using the trailer button will tell if problem in switch or wiring for trimming.

Jrock

Tried that. Held the trailer switch in for 15 sec. Trying to get the prop to blow out. But nothing. You can hold the switch in as long as you want. And nothing will happen, as long as it's above 4000 rpm.

floatingphil

Find a Merc manual for your drive and check the trouble shooting section. I recall that outboards won't trim out beyond 20 dergees (the limit of the trim rams) above 2000 RPM and that the trailer cylinder doesn't work above 2000 RPM either.
The Bravo may have a similar limit built in to it's trim system.

HiPerf2000

Have you tried running at 3500 - 3800 and start trimming up while pushing the throttle past 4000. If the trim stops when it hits 4000, i would have to say it's some type of electrical problem.

What year motor, what mods, etc.

FloridianSon

With the boat out of the water can you use the trim switch and get the ram to go to it's max of 21 3/4 inches center to center of the bolts and does the trailer switch over ride that and bring up the drive? If you can get it to do that my guess it is a pressure problem.

Jrock

Everything works, the way it should, up to 4000.
As I'm cruising, lets say around 3200 rpm, I can trim up and blow the prop out. Or put out a nice rooster tail.
If I want to run somebody from that cruising speed, thottle up past 4000rpm and then start to trim her out. She stays flat in the water. But if I bring it down to 3500 rpm . Trim up to where it should be on the gauge, thottle up, the drive will stay in that position. And she'll be riding on the pad with a nice rooster tail.

Thanks for all the imput I have received.

Turbojack

Here is shot in the dark. Since you replaced pump & all the parts, & we know the electric switch for trailering works. The ? is why over 4K? We all know the faster you go (4K) the more the load is on the outdrive. I would look for the gimbal ring or one of the other parts are loose when the drive gets loaded & it is binding up & trim can not overpower the bind. Is the trim gauge working? I am not sure but does the drive spline move in the coupling. I have grease fitting on the back of mine. Have you greased that?

blue thunder

Simpleton I am... is it possible the alternator belt is slipping?

BT

Turbojack

Another question along Blue Thunders line. Do you have volt gauge on dash. Does Voltage change when trying to trim? Or above 4K?