Still having issues and getting really frustrated

[cherokeeguy]

OK so i have recently purchased a 1984 270 Sundancer and throught out the past weeks have come to severly hate the dealership that i bought it from basicly everything they were supposed to do didn't happen and what they did do they have assed enough to make it through sea trials, any how the boat has a Merc 330 with a borg warner trans and a TRS out drive, it runs, drives and shifts awsome no complaints there the problem i am having is with the trim system, the out drive goes up and down just fine all the way and can be trimmed up while moving at a idle for going into islands and seams to be holding possition very well under the boat is under a load at cruising speed then the outdrive can't maintane the trim it just drops right back down, so far i have changed the relief valves, springs and o-rings in the pump, sucked out what looked like horible chocolate milk fluid and changed the fluid in the trim system, verified that there are no leaks and any trim lines inside or out, and blead the air out of the system and everything i do has no results at all could there be anything else I am missing, Also if this makes a difference or not (I think it is just the boat but this is my first 270) when you engage the 4 barrrels it actually torques the boat to the left untill the prop speed and the boat speed equalize.

 

[Four Suns]

You said all that in one sentence.... impressive.

 

[midway]

Are you bypassing fluid inside the rams, if the piston seals are weak you may be bypassing from the up side of the piston to the down which allows the drive to come down.

 

[Presentation]

You said all that in one sentence.... impressive.

Gary, I do agree with you.

By the third line I gave up trying to follow it.

If someone can translate this to English we can try to help.

 

[Morpheus]

Gary, I do agree with you.

By the third line I gave up trying to follow it.

If someone can translate this to English we can try to help.

What I got out of it he drives around with the drive up isn't that bad? No wonder the drive goes back down it doesn't want to be abused like that. If you need to trim the drive up to get where your going maybe you shouldn't be going there.

 

[fc3]

I think I understood what he wrote. Sounds like he needs a through rebuild of the pump and trim cylinders. Cylinder rebuilds are easy if the cylinder bores are OK. Pump isn't too hard to rebuild, either. Like any other hydraulic system, keeping it clean is important. No dirt at all.

Best regards,
Frank

 

[cherokeeguy]

Thanks for all the great advise, however i will go back over the situation so that mabye I can get some different ideas,

So far
The out drive pump has been rebuilt with new o-rings, seals, bypass valves, and springs
I have pulled the boat from the water and verified there are no external leaks in the system

The problem, The trim works fine going up, down and trailer mode when in the up possition or trailer mode and not under power the trim holds it's possition fine and all is well when under a load (useing to trim to equallize the boat and emprove gas millage) the trim can't hold position and always returns to the fully down possition

Due to the frequence of use, and distance driven it would be great to have this problem solved. Any imput is greatly appreciated

 

[midway]

The cylinders have to be bypassing fluid internally which allows the drive to drop, rebuild the cylinders.

 

[jg300da]

I have pulled the boat from the water and verified there are no external leaks in the system

The problem is an INTERNAL fluid leak. Either a faulty check valve or dirt lodged holding the check valve open in the trim pump unit causing the fluid pressure to bleed down. A common problem and as Frank mentioned, easily repaired/rebuilt.

 

[fc3]

The trim cylinders are leaking internally. These are for an Alpha, but yours are similar.

See parts b, c, k, l, i

See parts i, j, k, r, s

Best regards,
Frank

 

[rondds]

gary
stop scaring away the newbies!

my 10th grade english teacher, mr orsini, used to give us an exercise called "massive sentence combining." that sentence would have gotten an A for size but an F for syntax!

 

[cherokeeguy]

Just wanted to thank everyone for all the help. The boat is officially fixed, slowed down and took anouther look at everything and ended up finding the ball valve inside the valve body was leak past, I replaced the pump assembly and all is well. Thanks again for the help

 

[geriksen]

yup
rebuild or replace the trim cylinders
the milky fluid also points to the cylinders

 

[geriksen]

I would still rebuild hose cylinders if you get a chance
water in the fluid (the milk) is probably what caused the ball to stick initially

 

[cherokeeguy]

Yeah i was thinking that, so as a procaution I change all the fluid in the system so it is completly new (had this idea when i met the mechanic from the dearship that i bought the boat from and without knowing who I was he explained to me how they don't buy fluid but just reuse what comes out of the boats they scrap) luckilly i found the out when i only had about 3hrs on the boat so i pulled it and drained flushed and changed all fluids. Since there is no more chocolate milk in anything.

 

[RazorRobb]

Must be an english professor at Michigan. I've run across them before.:smt101:smt043:lol: