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Ranman
07-23-2010, 09:59 AM
Bravo drive will trim up all the way to trailer position just fine. Will not trim down properly. It starts off fine then after an inch or two quickly slows down to a snails pace. The trim pump "whine" has a weaker sound to it with maybe a slight chatter.

Fluid level is OK and everything has worked flawlessly until now.

I'm guessing either a bad ram or some chit caught in the pump valves.

I know there's a screen on the pickup tube, but it seem like if that were clogged, the drive would go down and not up (up takes from the reservoir and down puts fluid back).

ANything I can check/try before having the boat hauled out for diagnosis and service?

BUIZILLA
07-23-2010, 10:42 AM
do you have to haul the boat to remove the pump?

Ranman
07-23-2010, 10:53 AM
do you have to haul the boat to remove the pump?

No, I don't think so, but it would be nice to determine if the issue is a pump or ram. For sure have to haul out to replace a ram. Maybe have to haul out to diagnose... Not sure. Would hat to needlessly R&R the pump for no reason. It's back there in a tough spot.

MOP
07-24-2010, 06:15 PM
Before you tear into it remove the aft trim pin, lift the drive up and down by hand to see it moves freely. If the bushings and pivots are dry it can make it hard to move, the pumps push more then they pull.

Phil

Pismo
07-25-2010, 01:58 PM
Air in the system possibly.

Carbo
07-25-2010, 05:47 PM
Common is lift kept salt water boats.......The pump has a ton of pressure going up but limited going down. I bet you will see black streaking on the chrome part of the rams. This is the seals and wipers in the ram end caps. They have gotten salt and corrosion in the end caps and have clamped down on the chrome surfaces. Spraying lubricant externally on the rams will help but they will freeze again. Fix is to remove rams and replace endcaps and seals in the end caps. Not a bad job, endcaps screw in with a spanner wrench. If you going to do it yourself I could talk you through it. Retail on parts is about $75 cap and $20 seal kits each side.......you can get them at a discount online and I could give you part numbers if you need.

You can have someone stand on the drive (not running)hit the down button and the drive will go down for now....

Ranman
08-03-2010, 01:58 PM
Still trying to diagnose this issue and have some additional information that may help.

The drive still trims up without issue but will only trim down about half way. I I stand on the drive and someonehits the button, it'll go down the rest of the way (until I trim it up again).

Also, I've found out that there's nothing holding the drive down. In other words if I reach into the water and pull on the fully lowered drive, it will freely raise up to the "trailer" position. If I put the boat into reverse, the props will suck the drive up to the surface. The drive drops back down with a thud as well.

The Merc Service manual says for a drive that will not lower and one that "Trails" out on deceleration or reverse is most likely issues in the pump valves and seals.

It also says there's a possibility that the trim rams are leaking internally. I'm thinking that if they were leaking internally, the drive would not stay in the up position for long and would gradually fall.

Not sure, but I think I'm going to try pulling the pump and seeing if I can find the issue.

Anyone have a tip or trick on how to contain the trim pump oil when disconnecting the lines from the pump? The boat is in the water so disconecting at the rams is not an option. Thanks.

Carbo
08-03-2010, 04:59 PM
Sounds exactly like I described above....any black streaks on chrome? Any squeaking? Ton of pressure up..little down. The reverse going up and thunking down is strange though..that sounds like air but they self bleed to the reservoir though...strange......When they are tight in the end caps I do not think they would trail up in reverse. And if you get the drive all the way down fluid leaking will be minimal when you take the lines off the pump....leave the drive up and you will have a mess. If you took the lines off the pump with the drive up you would see if it is free to go down but you would have to catch the fluid.....messy.