About to Set it on fire (Plz Help)

[Crayfish]

So I have an 89 Maxum with the 5.0 mercruiser in it. Alpha one. Ive replaced coil, altenator, and powersteering pump all in hopes of getting it running before summer is over. Well the motor is solid now and runs good but all of a sudden my trim and tilt is giving me issues. It will go down just fine but I cant get it to come up. I am running ATF fluid in it. When I hit the up button the motor comes on and runs fine but the motor doesnt come up. Ive been told I need to bleed the lines. Could someone please tell me the proper way to do that? Also, after holding the up button for a while the motor will shut off like it gets too hot. Wait a little bit and it will run again. Any help is more than greatly appreciated as I just wanna go to the lake.

[mmwjr]

"About to Set it on fire (Plz Help) "

Do you want me to bring the gas or the matches?

The outdrive trim is a self bleeding system however it takes operating the drive up and down to do so. Since yours won't trim up I would try loosening the trim hoses on the hydraulic trim cylinders to see if that helps bleed the lines. Note you may have bad seals in the trim cylinders causing the problem so if after an attempt to bleed the system it still doesn't work I would rebuild or replace the cylinders.

[mmwjr]

I would also try disconnecting the trim cylinders from the rear of the drive and try operating them to see if they will extend.

[Crayfish]

Bring both please. haha

It was working fine the other day and then stopped working. Itll go up very slowly. What Ive done so far was drop the motor all the way down. Crack the lines and move it until fluid came out. Now were attempting to raise it while another person helps lift it up to hopefully push any air out. I am at a loss.

[Phillbo]

When it catches fire make sure it looks like an accident so you can file the insurance claim

Either the shaft wiper is getting stiff and with the help from the weight of the drive it will go down and not up, or the internal poppet valve on the cylinder piston is by-passing on one of the trim cylinders. The cylinders are double-acting so they will self bleed.

[NickNick]

Hey Crayfish. I thought the Mercruiser systems used some kind of solenoid valve(s) along with the pump to make things work. You could have a flaky valve.
I found this on line which has some testing procedures.
https://web.statler.wvu.edu/~mathews...20Eighteen.PDF

Give this a look just in case.
Nick

[mmwjr]

Originally Posted by NickNick

Hey Crayfish. I thought the Mercruiser systems used some kind of solenoid valve(s) along with the pump to make things work. You could have a flaky valve.
I found this on line which has some testing procedures.
https://web.statler.wvu.edu/~mathews...20Eighteen.PDF

Give this a look just in case.
Nick

The soleniods are purely electrical and provide power to the trim pump motor. The OP says the pump runs in both directions so the soleniods are not the issue. However there is valves in the pump body that can cause issues.

[jparsons121]

I’ve had better luck with 10w30 motor oil. My manual specs called for motor oil over ATF, as ATF can aerate and will take a long time to purge the air, affecting the ability to create pressure.


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[shrew]

If the pump is running, but the trim actuators are not moving, are you puking fluid either inside the boat or on the actuators? The seals on the actuators do go bad.

Have you tried reversing the lines to make the up button go down and the down button go up? In this case, the drive would still only work in one direction, but it would be opposite (down raises outdrive, up lowers outdrive).

If that works then its not the actuators, which would leave you with an issue with the pump itself.

[piermontmaxum]

i had a similar problem on my 2700 and ended up using the trailer trim for up and the throttle trim for down