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Johnson 70hp 1986 trim and tilt issue

F

Fungussface

New member
After my last boating outing I arrived back at the ramp to find tilt would not work. Trim tilt and raise we're all working when we went out. Motor noise but no lift when we arrived back at the ramp. Managed to get boat on trailer using release screw. When home checked fluid level and found full. With motor supported up running tilt pushes out the two trim rams very slowly. When motor is lowered manually onto them it is supported but no matter how long I try the tilt ram will not rise. If I try reverse the trim rams lower normally. There are no visible leaks on any rams. Can anyone help? I had the unit rebuilt 4years ago when the rams were leaking. The shop is now closed so can't ask them. Thanks. Colin
 
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It does sound like a low fluid level problem... strange if the fluid level is indeed where it belongs.

Fluid level is checked with the engine tilted up to its full extreme up position, locked in place. The reservoir should be full to the overflowing point... and refilled after running up and down a few times to purge any air. The unit is self bleeding.
 
joereeves said:
It does sound like a low fluid level problem... strange if the fluid level is indeed where it belongs.

Fluid level is checked with the engine tilted up to its full extreme up position, locked in place. The reservoir should be full to the overflowing point... and refilled after running up and down a few times to purge any air. The unit is self bleeding.
Click to expand...

Hi,thanks for the quick reply. As the motor would not tilt to trailer it home, I released the screw on the side of the unit enabling me to manually lift it. When I arrived home, i did the reverse and lowered the outboard manually so that I could flush the motor with fresh water. when complete I tried the trim tilt switch to raise it, but to no avail. I manually lifted the outboard again and used the support to hold it up. The fill screw is then easily accessed. The fluid level was at full to overflowing when I removed it. While the motor was in the up position, I used the trim and found that I could make the two small rams slowly move out to their full extent. When I lowered the motor onto these small rams manually, they held the weight if the motor in a tilted position. Although the motor for the trim/tilt could be heard clearly, the motor would not rise any further on the big ram. With the motor on the two small extended rams, i pushed the down switch on the trim/tilt and the two small rams retracted at normal speed lowering the motor fully. When I tried to tilt the motor again on the small rams, it did not move. I can only extend the small rams when there is no load on them. I was told to open the bleed screw and raise and lower the outboard manually a couple of times to purge the air. I tried this, but still no improvement.
Where do I go from here?
Thanks. Colin
 
Hi,thanks for the quick reply. As the motor would not tilt to trailer it home, I released the screw on the side of the unit enabling me to manually lift it. When I arrived home, i did the reverse and lowered the outboard manually so that I could flush the motor with fresh water. when complete I tried the trim tilt switch to raise it, but to no avail. I manually lifted the outboard again and used the support to hold it up. The fill screw is then easily accessed. The fluid level was at full to overflowing when I removed it. While the motor was in the up position, I used the trim and found that I could make the two small rams slowly move out to their full extent. When I lowered the motor onto these small rams manually, they held the weight if the motor in a tilted position. Although the motor for the trim/tilt could be heard clearly, the motor would not rise any further on the big ram. With the motor on the two small extended rams, i pushed the down switch on the trim/tilt and the two small rams retracted at normal speed lowering the motor fully. When I tried to tilt the motor again on the small rams, it did not move. I can only extend the small rams when there is no load on them. I was told to open the bleed screw and raise and lower the outboard manually a couple of times to purge the air. I tried this, but still no improvement.
Where do I go from here?
Thanks. Colin
 
joereeves said:
It does sound like a low fluid level problem... strange if the fluid level is indeed where it belongs.

Fluid level is checked with the engine tilted up to its full extreme up position, locked in place. The reservoir should be full to the overflowing point... and refilled after running up and down a few times to purge any air. The unit is self bleeding.
Click to expand...

Hi,thanks for the quick reply. As the motor would not tilt to trailer it home, I released the screw on the side of the unit enabling me to manually lift it. When I arrived home, i did the reverse and lowered the outboard manually so that I could flush the motor with fresh water. when complete I tried the trim tilt switch to raise it, but to no avail. I manually lifted the outboard again and used the support to hold it up. The fill screw is then easily accessed. The fluid level was at full to overflowing when I removed it. While the motor was in the up position, I used the trim and found that I could make the two small rams slowly move out to their full extent. When I lowered the motor onto these small rams manually, they held the weight if the motor in a tilted position. Although the motor for the trim/tilt could be heard clearly, the motor would not rise any further on the big ram. With the motor on the two small extended rams, i pushed the down switch on the trim/tilt and the two small rams retracted at normal speed lowering the motor fully. When I tried to tilt the motor again on the small rams, it did not move. I can only extend the small rams when there is no load on them. I was told to open the bleed screw and raise and lower the outboard manually a couple of times to purge the air. I tried this, but still no improvement.
Where do I go from here?
Thanks. Colin
 
I neglected to mention...... be sure to screw the reservoir fill screw plug back in after each filling, BEFORE you run the electric motor or else the fluid will escape/pump out when in the down mode.
 
Possibly you have encountered a hydraulic lock situation......................

(PTT Hydraulic Lockup)
(J. Reeves)


If the engine has been trailered without having both of the trim rams pulled in, or trailered without even having the engine being supported by the trailering support, it is possible for the PTT to encounter a hydraulic lock up. The slight up and down motion, when trailering allows over 1700 psi of oil pressure to build up on the wrong side of the oil pump. Since the oil pump cannot exceed that 1700 psi, the unit is effectively hydraulically locked into position (the elec motor runs and does nothing).


The proper method for trailering is to have the engine in a full tilt position and resting on the trailering support bracket, then have both trim rams pulled in to a point where the engine makes a jerking motion. At this point, immediately take your finger off of the PTT trim switch. Now, quickly and sharply, tap the PTT up button. This removes the vast majority of down hydraulic pressure but at the same time, the engine is solidly locked into position and cannot rock up and down.


(The Cure)
Have the engine in the up position and supported so that it cannot fall. Look straight at the PTT assy.... you will see what looks like a large slotted screw on the port (left) side of the PTT assy, but which is in fact a check valve. Remove that valve and what you find inside which is a shuttle valve, and a spring on each end of that shuttle valve.


After you've removed those items, look straight inside of that chamber. You'll be looking at the reverse side of another check valve. Look at the hole in the backside of the valve you removed. You will need a punch that will fit inside of that hole.


Now, place the punch inside of the hole in that check valve that is still in the unit, and tap it rather sharply with a hammer. It will take quite a rap but the idea is to unseat the valve to release the hydraulic pressure. Watch your eyes as when you do release the pressure, it will have a tendency to spray out somewhat.


After releasing the pressure, reassemble the shuttle valve, springs, and outer check valve. Fill the oil reservoir with PTT fluid, having the engine in the extreme full tilt position. That's it.

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:

http://shop.ebay.com/Joe_OMC32/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
 
Hi. Thanks for this. When we trailed the boat home the outboard was supported by the trailer in support as the trim did not work and I had to release the engine using the manual override screw on the right side. While we were on the water we hit a submerged log. Is it possible this caused the lockup?
i have identified the screw you have said in your post. I will attempt the cure on the weekend and let you know how I go. Many thanks. Colin
 
Joe, I think the method you described was used back in '78 before they came out with the expansion relief valve in the unit. That lock up problem went away after that. And yes, I have broken some units free with your method.
 
Boobie said:
Joe, I think the method you described was used back in '78 before they came out with the expansion relief valve in the unit. That lock up problem went away after that. And yes, I have broken some units free with your method.
Click to expand...

I've encountered a few units with that hydraulic lockup that incorporated the expansion relief valve.
 
joereeves said:
I've encountered a few units with that hydraulic lockup that incorporated the expansion relief valve.
Click to expand...

Hi,
It has been a couple of weeks since yo r reply and I have been working weekends. I had the opportunity today to try the procedure you suggested. I removed the large screw on the left and the spring valve behind it. Some fluid ran out. When I pushed a long thin punch against the valve on the other side, it moved with moderate pressure, but did not need to be tapped. There was no rush of fluid, unfortunately.
I replaced the valve and screw plug, refilled the reservoir and lowered the outboard manually to its lower position. When I tried the trim/tilt button again the motor was going and I could hear a couple of bubbles pass through. The two small tilt pins came out slightly, but not enough to lift the motor. I tried on an d off for about 10 minutes but no lift. When I tried reverse, the pins retracted quickly.
I had read in another post that I may have to prime the system by lifting the motor up and down manually with the plug on the side released. I did this 6 times and could feel the resistance building each subsequent raise. I then tightened the manual release screw and tried the tilt button again. Still no lift.
There seems to be pressure when I press the down button, but not in the upward direction.

Is it possible an o ring on the lift side has gone?

What do I do now? Do I buy a kit and put all new o-rings through the system.

Getting really frustrated as the fish are biting and I am marooned.

Many thanks in anticipation.
Sincerely,
Colin
 
Fungussface said:
Can I overhaul the tt system myself?
Click to expand...

With the proper specific manual for your engine, I would think so. Whatever special tools you might need could no doubt be somewhat duplicated via a auto part store.

Send me off your email address via a private message here and I'll send you the oil flow charts showing pressure via both modes. This would allow you to see exactly here pressure is applied in either mode... has always helped me with weird problems.
 
joereeves said:
With the proper specific manual for your engine, I would think so. Whatever special tools you might need could no doubt be somewhat duplicated via a auto part store.

Send me off your email address via a private message here and I'll send you the oil flow charts showing pressure via both modes. This would allow you to see exactly here pressure is applied in either mode... has always helped me with weird problems.
Click to expand...


Thanks Joe,
my email is [email protected] .
I have a retired mechanic closeby and he is bound to have the tools and would be interested in the challenge. It gets him away from the wife for a while. :)

Sincerely,
Colin
 
Hi Joe,
Ken, a local here in Ipswich Queensland, read the post and email came over this morning to help. We removed the PTT unit and opened all the valves on the back. They all looked fine. While on the bench we tried the system and found that it operated normally. Somehow we have released the airlock, refilled the reservoir and refitted the unit into the boat. It seems to be working. Thanks for your advise and to Ken for giving up his Sunday morning to lend a hand.

One other question. is there a termal sensor in the motor. We had a couple of issues when lowering and raising repeatedly. the motor stopped for a few seconds then started aain. When it was cool, it worked up and down without a break.

Also Ken was saying that there is only a rectifier in the motor with the potential to overcharge the battery. Is there an economical way to prevent the battery from overheating.

Thanks for all your help. Great selection of parts also. I may be needing a few.

Sincerely,

Colin
 
The charging output of that stator alternator is so low... 6 or 9 amps, somewhere in that range, that it will never overcharge your battery. Put that fear out of your mind.

If the question lingers and bothers you, install a volt meter and if the voltage starts to increase over 12.5... turn on your lights and radio, whatever, to use up some of that power.

On the PTT lockup problem, should that ever happen again, the following might save you some time and trouble:

(PTT Oil Pump Air Lock)
(J. Reeves)

When the PTT unit is as it should be, the electric motor runs, the manual release valve is closed, the unit is full of lubricant, and nothing works, the usual problem is an air lock under the oil pump Proceed with the following.


Engine in full tilt position. Remove reservoir fill plug screw. Insert a air nozzle up against the reservoir fill hole with rags (or something) packed around it to obtain a tight fit. Apply just a slight amount of pressurized air (10 psi resommended) to the reservoir. This will force the oil under the oil pump to remove the air lock. DO NOT go crazy with the air pressure (15 psi tops!).




The circuit breaker question.... the older 3 wire electric motors had a breaker built into the motor but whether there's one incorporated within the 2 wire motor slips my mind. I would assume there is as there is no fuse in that line.
 
Thanks very much.
It is interesting how far the around the world the forum stretches.
Hopefully the end to my problems.

Sincerely.

Colin

joereeves said:
The charging output of that stator alternator is so low... 6 or 9 amps, somewhere in that range, that it will never overcharge your battery. Put that fear out of your mind.

If the question lingers and bothers you, install a volt meter and if the voltage starts to increase over 12.5... turn on your lights and radio, whatever, to use up some of that power.

On the PTT lockup problem, should that ever happen again, the following might save you some time and trouble:

(PTT Oil Pump Air Lock)
(J. Reeves)

When the PTT unit is as it should be, the electric motor runs, the manual release valve is closed, the unit is full of lubricant, and nothing works, the usual problem is an air lock under the oil pump Proceed with the following.





Engine in full tilt position. Remove reservoir fill plug screw. Insert a air nozzle up against the reservoir fill hole with rags (or something) packed around it to obtain a tight fit. Apply just a slight amount of pressurized air (10 psi resommended) to the reservoir. This will force the oil under the oil pump to remove the air lock. DO NOT go crazy with the air pressure (15 psi tops!).




The circuit breaker question.... the older 3 wire electric motors had a breaker built into the motor but whether there's one incorporated within the 2 wire motor slips my mind. I would assume there is as there is no fuse in that line.
Click to expand...
 
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