Trim/ tilt help

[Dan93]

I am relatively new to working with boats, my background is mainly cars.

Ihave a late 70's Blue Band 70hp Thunderbolt Start with power trim/ tilt that isn't working.
You can hear the remote pump trying when you hit the button to raise and lower but the enginge doesn't move.
I have checked the batteries, checked the amount of fluid in the pump (it's full) and tried to bleed it but when I loosen the nipple and hit the button to raise the engine, nothing comes out.
I don't really know what else to try outside of replacing the lines or entire trim/ tilt assembly itself, which I don't even know if other trim assemblies would fit the engine.

Image attached for reference

 

[Chris1956]

So you loosen one of the bleed screws, run the pump and and no oil comes out? If that is the case, perhaps the motor armature is no longer turning the pump.

You can loosen on the the lines on the bottom of the pump/reservoir and see if oil shoots out there. If not, either the control valve is somehow stuck (not sure how that would happen), or the pump is not being turned. the control valve is easily removeable. Watch not to loose the o-rings.

You can pull the bottom of the reservoir off and inspect the pump. Maybe is stripped? Maybe the armature somehow popper up. Are the motor bolts tight? is the top of the motor bolted to the body?

 

[merc850]

There's a procedure for bleeding [some cylinders use Allen screws] that fitting on the top of the cylinder is a grease fitting, grease it and the lower bushings when you remove the trim cylinder.

The pump has a knob at the front for the reverse lock

 

[Dan93]

So you loosen one of the bleed screws, run the pump and and no oil comes out? If that is the case, perhaps the motor armature is no longer turning the pump.

You can loosen on the the lines on the bottom of the pump/reservoir and see if oil shoots out there. If not, either the control valve is somehow stuck (not sure how that would happen), or the pump is not being turned. the control valve is easily removeable. Watch not to loose the o-rings.

You can pull the bottom of the reservoir off and inspect the pump. Maybe is stripped? Maybe the armature somehow popper up. Are the motor bolts tight? is the top of the motor bolted to the body?

Correct, no oil comes out when the bleeder screw is loosened, even took it completely off to make sure it wasn't clogged and no oil came out when the screw was entirely removed.

The pump/ resevoir was secured tightly when completing this test. I'll try the other steps you mentioned and let you know how we go.

 

[Dan93]

There's a procedure for bleeding [some cylinders use Allen screws] that fitting on the top of the cylinder is a grease fitting, grease it and the lower bushings when you remove the trim cylinder.
View attachment 358056
The pump has a knob at the front for the reverse lock
View attachment 358059

Thank you very much for that mate, much appreciated

 

[QBhoy]

When you say the bleed screw…do you mean the manual release valve on the side ? Make sure that’s screwed in fully and not passing. If it is..the oil just reliefs and won’t give pressure.
Have a good look around the whole thing. Could be wrong, but there is a very good chance that this trim tilt system has been an afterthought. Most of these originally came with just gas assist raising and lowering and trim was locked or adjusted with a pin. Check the pin out too.

 

[merc850]

This is an original trim system with a pump in the boat and 2 rams at the side, the "gas assist" shocks were to prevent the motor from kicking too far out of the water and a mercury switch cut off the ignition for a second while the motor re-entered the water. PT was an option.

 

[QBhoy]

This is an original trim system with a pump in the boat and 2 rams at the side, the "gas assist" shocks were to prevent the motor from kicking too far out of the water and a mercury switch cut off the ignition for a second while the motor re-entered the water. PT was an option.

No doubt you’ll know more than I about it…but just remember as a younger man…when more of these were still common…most or all of them I knew had to be tilted up by hand when going into the shore or beach. By means of what I presumed was called the gas assist system they had. Maybe I have the name wrong. The last one I was familiar with and operated often was an old 50hp around the same age.
The engine featured in this post I’d think is from the mid 70’s. late 70’s at her newest. Power trim on an engine that size and age, would be a rare thing I’d think.

 

[Chris1956]

The OP does have PTT on that motor. It was an option. The manual shock absorbers are replaced by a bracket and longer/larger hydraulic cylinders, plus 4 hydraulic hoses and a motor/pump/reservoir unit in the boat.

 

[merc850]

If he follows the instructions I've posted it should work, I have the same system on my motor and have done the procedure.

 

[Dan93]

Is it possible to swap this unit with a more modern one? As in, can I swap the entire trim tilt assembly for a more modern one?

I cannot manually pull the lower unit out anymore to take the slack out the rams to start trying to bleed.

 

[Dan93]

Or can I completely remove the hydraulics and manually tilt it untl I can swap the outboard?

 

[Chris1956]

You can remove the hydraulics, however, the motor would pop up in reverse, and under deceleration. It would therefore be better to leave the trim cylinders on and remove the rest of the system.

However, I would recommend you find out why the PTT is not working. The knurled knob on the base of the pump is turned CCW? That is for normal operation. Turning it CW will allow you to raise the motor manually, but that is not necessary to bleed the system.

The pump/reservoir is self bleeding, but must be filled to bleed the cylinders manually. Have you done that?

To bleed the "up" side of the cylinders, you must remove them from the engine and face the up bleed screw up, and then run the pump to get all the air out.

Merc850 has posted the exact instructions necessary to bleed your system.