worried about my mercruiser trim pump fluid

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cjones50

Cadet
Joined
Aug 16, 2009
Messages
9
hopefully you guys can help me out. the other day my drive got stuck down, and i was worried i wouldnt get the boat out of the water. not sure if it was wiring or battery or pump or some sort of safety device. but i drove around for ten and it started working again, and worked for the rest of the afternoon. just kind of creepy. i checked the fluid and it looked like a vanilla milkshake. look like its time to change it and i was wondering how to do it correctly. i know i'm capable if it, know where everything is, just want to know the steps to do it right the first time, and not skipsomething and waste new fluid or get the cylinders stuck. thanks everyone

1994 bayliner capri
mercruiser 3.0 135hp
alpha 1 gen 2
quicksilver command 3000
 
QC

QC

Supreme Mariner
Joined
Mar 22, 2005
Messages
22,783
Re: worried about my mercruiser trim pump fluid

Moved this to the I/O section . . .
 
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bigbrownbuku

Master Chief Petty Officer
Joined
Sep 17, 2004
Messages
885
Re: worried about my mercruiser trim pump fluid

sounds like you have water in your trim system, this is bad. find out where its getting in and repair it.
 
erikgreen

erikgreen

Captain
Joined
Jan 8, 2007
Messages
3,105
Re: worried about my mercruiser trim pump fluid

FYI, the most likely place is the seals on the trim cylinders, followed by the screw connections at the base of the transom housing.

It's not good to have water in there, but as far as I know it won't destroy anything quickly. Just fix the leak, then replace the fluid (my fluid is 5W-20 oil, yours may be something different).

Erik
 
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cjones50

Cadet
Joined
Aug 16, 2009
Messages
9
Re: worried about my mercruiser trim pump fluid

thanks guys, but thats why im on here. i deffinately want to reapair any leak. what i need to know is how i go about changing the fluid so i dont burn anything up or leave a bubble and get the system stuck. thanks
 
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gatesmoonwalker

Cadet
Joined
Sep 18, 2008
Messages
20
Re: worried about my mercruiser trim pump fluid

Never fear being stuck in the water with trim problems. Just pop the clips and pull the shaft out of the cylinders. Lift the outdrive up by hand a tie it up for a quick fix to get you home.
 
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cjones50

Cadet
Joined
Aug 16, 2009
Messages
9
Re: worried about my mercruiser trim pump fluid

thats a good idea, i woulda been kickin rocks if i didnt think of that. but back to my initial question... can anyone tell me how to properly drain and fill the fluid? or a direct link to a site or someone who does.
 
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gadget73

Petty Officer 1st Class
Joined
Jun 20, 2009
Messages
308
Re: worried about my mercruiser trim pump fluid

Last I changed fluid in mine, I pulled the whole pump assembly out of the boat and turned it over to dump it. There are a lot of baffles inside that reservoir so it makes sucking the fluid out pretty difficult. Its possible to seperate the reservoir from the pump for better cleaning. Theres a small screw on the bottom side of the plastic tank. If that screw looks really rusty, you might not want to play with it because theres a chance it could snap. If you do pull it, I'd suggest using the extra access to clean up all the electrical connections on the pump assembly. Pull off the wires from the solenoids and clean them up, and clean the buss bar between the solenoids up.

As for fluid, mine (1993) seems to indicate power steering/trim fluid according to the fluid chart on top of the engine cover, but the owner of the local marina told me to just use transmission fluid which seems to be doing just fine. Apparently the manual indicates motor oil, so I guess it doesn't really matter all that much. Its just a hydraulic system, so in reality any fluid will do the job, though it should be made from some sort of oil for lubrication reasons.

Typical leak spot for the trim system is the end seals on the drive lift cylinders. If you have some random metal and maybe rubber bits hanging on the shafts, then the end seals are toast. If you don't have parts hanging out, I'd still bet thats the source of the water.
 
erikgreen

erikgreen

Captain
Joined
Jan 8, 2007
Messages
3,105
Re: worried about my mercruiser trim pump fluid

As far as draining the system... either pull the pump, or you can use the pump to push most of the oil/fluid out by disconnecting the cylinders and running the pump. Start with the cylinders retracted (drive all the way down) or there'll be a lot of oil in them that you won't get rid of.

Erik
 
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