TOPIC: 1967 Mercruiser 160 Trim Problems

Howdy all,

I am having trouble with the trim on my boat not holding. My 1967 Gulfstream has a Mercruiser 160 I/O on it. I figured someone here has a way better understanding than I do on this sucker.

Here is what's going on.

* When motor is trimmed up for trailering it will bleed down in about a 5 hours. I have noticed this while she's on the lift.

* If I grab the sterndrive and lift up and down I can get it to move about half its full travel in either direction. I can hear what sounds like air being bled when I manually lift the stern drive.

* I checked the fluid and it appears to be low.

What should I do? Just add hydraulic fluid? Do you think the system has air in it and needs to be bled if so how?


Any help is appreciated.


Hec
Please note: although no board code and smiley buttons are shown, they are still usable.

refill and check for leaks. it should bleed by running it up and down a few times. recheck the level.

1. Could be the the "lower down" valve / screw backed off. The knob located on the hydraulic unit make sure it's turned all the way clockwise.

2. Could be the packing (seal) on the hydraulic cylinder piston. A simple way to check this without a gauge is to raise the engine all the way up and loosen the top hose then try and raise it again. If you have hydraulic oil coming out of the cylinder then the packing on the cylinder piston is leaking. NOTE: When you loosen the top hose have a drain pan / bucket under the unit to try an prevent a mess (good luck).

3. Like Mr. Bernard said the unit may be low on oil and air is compressing in the system.

4. Holding valve.

Let us know what you find and if its the holding valve I will let you know how to check that.
Pete a.k.a. DelRay

DelRay,

I will check it out tonight. What type of fluid should I be using in the hyraulic system? I have been using the Mercruiser Trim fluid sold at the Marina. I have heard to use anything for 30 wt oil to tranny fluid type F.

Hec

dave bernard,

Thanks I will try this tonight!

Hec

You have a MerCruiser 160. In 1967, there was power TILT standard & a power TRIM option. Which system do you have?

Are there 2 lines to each cylinder or only 1 line?

Regardless of trim or tilt, the unit should only move very slightly by hand. You do have air in the system. And unlike stated in an earlier post, the system will not self bleed its self. There is a procedure for removing the cylinders at the aft end and then holding then horizontal or letting them droop down to bleed.

Also, there is no mechanical bleed down screw on the black high pressure pumps with TRIM. I don't remember one on the TILT pumps either, but I am not sure.

Jim

jimandros

I have the power trim option. There are two lines on each lift cylinder. Any idea of what type of fluid to use?

Hec

Seems hard to find a pint of hydraulic fluid anymore but power steering fluid will work or mercron (chevy) trans fluid

DelRay,


I found a little sticker on the pump that sez,"Use only SAE 20 wt motor oil" I don't think I can get 20wt at the parts store. 10W30 will have to due eh?

Hec

Old school in hydraulics was 10w motor oil. I think you need to see what other people might say about this.
Pete

Did you get it working?

DelRay,

Not yet. I was planning on taking my boat up to Lake Ottertail, MN for Labor day but the weather report was crummy. So we left the boat home and therefore I did not work on it. We got back late last night. I will tinker with the trim this weekend though. I will keep you posted. BTW I found my Mercruiser Service Manual and it states to use either 10 W 30 wt or 10 W 40 wt oil for the trim. So I picked up a quart of 10 W 30. Lets see what happens.

Hec

Thanks for the reply. I will be out of state this weekend so if you get a reply from me I will monday

DelRay

This past weekend I filled up the hydraulics resevoir with 10W30 oil. I cycled the lift up and down about 10 times. There was still air in the system. So I proceeded to bleed the air per the mercruiser manual. I first unhooked the two lines on each cylinder. In doing so I noticed that the up port on the Port side cylinder had stripped threads. So I am in a holding pattern until I replace the cylinder. I will probably replace the pair while I am at it. There is a guy on E bay selling a pair with hoses for $225. I will probably go that route. Once the new cylinders are on I will bleed the system as planned on and hope for the best.

Hec

Got Back in last night from Bentonville Arkansaw....almost Tulsa Oklahoma.
Thanks for the reply. Striped out huh? The threads in the cylinder? Do you all have a hydraulic repair place local? Like Areoquip hydraulics or Parker Store? They might be able to repair the cylinder. I have been in the hydraulic repair buisness for many years Bulldozer, backhoe, forklift etc...its common to repair cylinders is it the end where the chrome rod comes out or the end thats caped (no rod coming out)

You may have one cyl or the other. that is leaking internally. If you still have this problem after the rest of the checks these fine gentlmen have given. This should be checked by your Marine Tech he has the right equipment for the job.

DelRay,


The hydraulic port closest to the transom has stripped threads. This port is for the "UP" circuit.

Hec

Del Ray and others,


Well the winter season is over here in Nebraska and it is time to get the boat ready for another season. As we left off last year, I was having hydraulic issues. The outdrive would not stay up or would come up if the boat was in reverse. I purchased a new used set of hydraulic rams and proceeded to bleed the system per the Mercruiser Manual. By the way I am using 30 wt oil in the system. I am still experiencing the outdrive dropping after it has been trimmed up. I poked my head around the engine compartment and found a fresh oil leak coming from the reverse lock out valve. I removed the reverse lock out valve and dissassembled it. I found an oring with a piece missing in it. I have compared the pieces that make up the reverse lock out valve against and exploaded view diagram and found another O-ring to be completely missing. I guess this valve is supposed to keep pressure from bleeding down in the rams and allowing the out drive to come up while in reverse. This may explain why the out drive comes up in reverse but I don't think this explains why the outdrive bleeds down and lowers? I have orderd all the O-rings and washers to reseal the reverse lock out valve and I have ordered a new trim valve assembly. I am guessing there is pressure being allowed to leak from each side of the two circuits through the trim valve assembly.

Am I on the right track?

Hec

could be air in the system from the leak.