Tilt/Trim not working after reinstalling outboard motor

Slacker411

Petty Officer 2nd Class
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Apr 12, 2013
Messages
118
I just replaced the transom, stringers, and deck on my Bonito bowrider boat. The motor works great and cranks right over as it should. Before removing the motor to do the above mentioned work the tilt/trim worked fine. In the nearly one year spent sitting in my garage the trim cylinders with 2 ram arms is not working. The trim/tilt motor is working and sounding pretty much like it used to but after putting 10w30 oil in the tilt/trim motor resevoir it seems like the system is not priming itself with the hydraulic fluid and the engine will not go up or down. Is there a trick to priming the trim/tilt system and bleeding out all the air? I have been able to move the motor up down and placed it in the full up position and put 2x4's underneath too keep it from going down. with the engine in the up position I tried to prime it by pressing the trim "up" switch on my controls. I can not see any signs of leaking fluid anywhere either. This one has me stumped. Any help would be appreciated.

-David
 

Slacker411

Petty Officer 2nd Class
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Apr 12, 2013
Messages
118
Re: Tilt/Trim not working after reinstalling outboard motor

I thought of adding a bit more info:

With the motor in fully trimmed "up" position I have tried depressing the trim "up" button in hopes it would send the hydraulic fluid into the trim cylinders and help keep the motor upright. As soon as I remove the 2x4 holding the motor up..it will go down. Would it make a difference if I had someone press the trim "up" switch on the controls while I physically lift the motor up by hand? Also, my method of trying to bleed air from the system is: Do the above mentioned steps with the dipstick/fill cap off. I filled it up with oil until it was overflowing and would not take any more oil. Try to run the trim switch and the oil level does not drop. To bleed the system of air does anything have to be done to the manual release valve? At one point I opened the manual release valve with the engine already in the down position and then moved it into the up position. I cannot tell for sure but it sounded like air was escaping through that valve as I pushed the engine up. It made a similar noise when I put the engine back down, but I can't tell if it was sucking in or blowing out air. Again, any help would be appreciated. When I get off work in the morning I will try to post some pictures.
 

sam am I

Commander
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Jun 26, 2013
Messages
2,169
Re: Tilt/Trim not working after reinstalling outboard motor

10W30 oil?............No no!

Think I'd start by draining out all that motor oil as best as possible first by removing the manual relief valve, at same time check it's o-rings and that it's not broke, the tip and rings should look something like this.
MRV.jpg

Its been noted here in some resent posts that o-ring "C" can break off along with some of the nylon tip and cause issues.


Then...

Check, Fill and Purge - Power Trim System

TO CHECK:CAUTION

Tilt outboard to full “Up” position and engage tilt
lock lever before checking fluid level. System is
pressurized. Extend trim and tilt rams fully to depressurize
system.

Remove fill plug and O-ring. System is full when oil
level is present at filler hole. Tighten fill plug securely.
NOTE: Automatic Transmission Fluid (ATF) Type F,
FA, Dexron II or Dexron III may be used.


TO FILL:

IMPORTANT: This trim system is pressurized.
Remove “Fill” plug only when outboard is tilted
to the full “Up” position or the trim/tilt rams are
fully extended. Retighten “Fill” plug before tilting
outboard down or retracting tilt/trim rams.
Remove “Fill” plug and O-ring. System is full
when oil level is present at fill hole. Tighten “Fill”
plug securely.

TO PURGE:

IMPORTANT: Fill plug and O-ring must be tightened
securely before purging system.
IMPORTANT: Run Trim System in short “jogs”
until pump is primed and trim system moves. If
trim motor is run without priming pump, driveshaft
failure could result.

Cycle outboard through entire trim/tilt range 4 times.
Check fluid level after purging system.
Push down on outboard when trim rams are slightly
extended. If rams retract more than 1/8 in. (3.2 mm),
air is present in system. Cycle system again and
check fluid level.
 
Last edited:

Slacker411

Petty Officer 2nd Class
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Apr 12, 2013
Messages
118
Re: Tilt/Trim not working after reinstalling outboard motor

Thank you for the info. The hydraulic pump motor I have says on it to use either 10w30 or 10w40 oil. As does my clymer manual. I will try to purge the system in the morning i guess.
 

sam am I

Commander
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Jun 26, 2013
Messages
2,169
Re: Tilt/Trim not working after reinstalling outboard motor

Ahhhhhhh, okay. Wasn't sure of the type, just took a shot and went by my merc manual.

Year and type?
 
Last edited:

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,077
Re: Tilt/Trim not working after reinstalling outboard motor

agreed the 10w30 is the correct oil.- Make sure the manual release is in the correct position.---Crack the fittings on the trim cylinders and see if air is present.
 

Slacker411

Petty Officer 2nd Class
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Apr 12, 2013
Messages
118
Re: Tilt/Trim not working after reinstalling outboard motor

The trim cylinders probably have air in them as when I took the motor off the boat I disconnected both of the lines leading from the pump/motor to the cylinders that raise/lower the outboard. The motor sat with those lines disconnected for about a year, when I finally went to reinstall the outboard I noticed there was oil underneath the motor and stand that must have leaked out from those cylinders. I will post pics when I get off work to help explain. If by chance those cylinders are dry will it just take me longer to prime the system?
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,077
Re: Tilt/Trim not working after reinstalling outboard motor

First verify that the manual release is in the correct position.---------Then crack fittings on the cylinders to see if air comes out.
 

carholme

Rear Admiral
Joined
Sep 4, 2010
Messages
4,845
Re: Tilt/Trim not working after reinstalling outboard motor

As you left the lines disconnected for a year, one would think air may be the least of your problems. It does not take much contamination in the system to ruin your day.


Gerry
 

Slacker411

Petty Officer 2nd Class
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Apr 12, 2013
Messages
118
Re: Tilt/Trim not working after reinstalling outboard motor

So good news and bad news. I figured out what the problem was, but now have another problem to take care of. The dipstick screw on the pump broke off a couple days ago, which I failed to mention. I took the pump apart to be able to get at the dipstick portion sitting in the resevoir and twist it out. Turns out there was a little coupler piece that I didn't realize had dropped out when I split the motor from the resevoir/pump. I found it on the floor of my garage this morning, reinserted it, and PRESTO I was able to prime the lines and get the tilt/trim to work.

The bad news is when I moved the hydraulic pump unit one of the hydraulic lines that is sheathed in woven metal brushed against an exposed electrical wire on the relay which caused a spark/small fire that I put out immediately but this damaged the line and there is a leak in it now. So, now I get to search for a new hydraulic trim line. Anyone know a good source?
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,953
Re: Tilt/Trim not working after reinstalling outboard motor

Slacker, What year is that model? Sounds like 70s or early 80s. Maybe you have MerCruiser PTT parts on it? PTT cylinders that are separate from the pump/reservoir which is what your's sounds like, have a different bleeding procedure than integrated PTT units.
 

merc850

Commander
Joined
Jul 7, 2010
Messages
2,046
Re: Tilt/Trim not working after reinstalling outboard motor

To do a complete job on the bleedingpower-trim-bleeding.jpg, you can find lines on ebay.
 

Slacker411

Petty Officer 2nd Class
Joined
Apr 12, 2013
Messages
118
Re: Tilt/Trim not working after reinstalling outboard motor

Its a 1978 Mercury V-1500 V6 150hp outboard. I could not find the same hoses on iboats but I did find one on **********. Can't wait for it to arrive!
 
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