1985 Force Tilt/Trim Issue

[davijc02]

I replaced my trim valve body due to the old one bleeding down. When I went to raise the motor the switch stayed engaged and the motor continued to run in the full up position for a several seconds until I could stop it. Once stopped I couldn't get the motor to lower via the switch. So I unscrewed a allen plug on the valve body and lowered the motor to full down.

I then installed a brand new tilt motor and switch and still the motor won't raise or lower. I verified the motor is spinning in both directions via the switch. However it seems as if its not pushing any fluid. Also, I try to manually lift up the motor but it will only come up 3-4 inches. It almost seems like its a hydraulic lock. Any way to relieve the pressure. This model doesn't have a manual relief valve.

 

[davijc02]

Its also unfortunate that I purchased the new trim motor as after I replaced the motor I hooked the old one to a battery and it worked in both directions.

 

[Jiggz]

Most of the time it is not a matter of just replacing parts but more on troubleshooting and identifying the faulty parts that is the hardest thing to do. In your case, you need to bleed all pressure first by loosing the tubing connection from the valve body (VB) to ensure no oil pressure is holding the system. Next is to read up for troubleshooting and testing procedures on the sticky post. Here's a link to it.

http://forums.iboats.com/forum/engi...outboards/659768-88-force-85hp-trim-drop-help

 

[davijc02]

Once I loosen all the tubes to the valve body should I try and cycle the motor up and down manually to relieve the pressure?

 

[Jiggz]

No, loosening the tubings will relieve the pressure if there is any. Do not cycle the unit until all tubings are re-tightened. Then conduct the test procedures in the link. There is a possibility with the overpressurization that happened the O rings in the *** or trim cylinders have been busted. So doing the test procedure will identify this.

 

[davijc02]

Well I give loosening all the lines a shot in the morning. I've had the motor and valve body off a few times already. So I would have figured any trapped air would have escaped already. However, if that doesn't release any air I don't think I will be able to do those test procedures. As of right now I can't raise the motor at all with the pump or manually higher than the 4 inces.

 

[davijc02]

Operating via the switch does nothing for raising. I can feel the pump kick on with my hand. So really the only way it goes up is manually.

 

[Frank Acampora]

If you can raise the engine 3-4 inches by hand, then you probably have an airbound situation in the tilt cylinder. Does it rise easily then feel :spongy" as you reach the limit? That is air. Does the trim cylinder work at all when you activate the motor to lower the engine? Did you insert the motor or pump correctly? There is a flat on the end of the motor shaft which engages the driven gear in the pump. If this does not enter the slot in the gear, the tilt/trim will not work. The motor may be jammed and feel like it is turning (humming) but in fact it may not be. Some of the motors have a bimetal overheat switch built inside. If you run the motor too long at the upper limit, the switch will open and the motor will not work until the bimetal has cooled.

 

[davijc02]

Frank,

The tilt/trim does absoulutely nothing when I hit the switch in either direction. I can hear the motor click on and feel it come on when I press the switch. I made sure that the flat portion of motor shaft seated correctly into the valve body. When I say I can manually raise the motor 4 inches I literally grab the lower leg and attempt to raise it. It moves freely about 4 inces then the rams won't extend any more no matter how hard I try. The motor won't stay in that position either it just falls all the way back down.

 

[Frank Acampora]

That is an air bubble in the tilt cylinder. However, you should be able to bleed it simply by tilting up and down a couple of times. THUS: you have a problem in the pump itself too. I have been there before and it is frustrating. But double check the reservoir to be certain there is enough oil in it. Also, sometimes the trim ram becomes stuck in full out trim and will not return. It somehow gets slightly cocked in the bore. If this is the case, smack it hard a couple of times with a hammer to try and free it--that is, after you manually get the engine tilted up

If the pump is the one with three fittings on the side and one on the bottom, the front two fittings are the up circuit and the back two are the down. It is not necessary to loosen all four. One in the front and one in the back is enough.

 

[davijc02]

That is exactly the pump that I have. I will loosen the fittings that you suggested which will hopefully release this air bubble. The pump is brand new which sucks if that thing already crapped out. Are you thinking that while the motor was running in the full up position for that extended periord of time something may have broke? If so, what is most likely the culprit in these things and can I fix this myself?

I did remove the plug with the allen head on the front of the pump which is why my motor is currently in the full down at this moment. I wouldn't think that would have messed it up though.

Appreciate the help though.

 

[Jiggz]

Can you post a pic of your T&T system. Just to make sure we are taking on the same style. If loosening the tubes at the VB still would not allow manually raising the motor to its limits, then the next move is to disconnect both tubings from the tilt cylinders and see if that will allow you to manually tilt the motor all the way. If not then you need to open and inspect the tilt cylinder.

If it allows you to manually raise the motor with both fittings disconnected from the tilt cylinder, try reconnecting the tube fittings starting with the return line located at the top of the tilt cylinder. Then manually raise the motor again. If it allows full raising, then reconnect the bottom tube fitting and test again. Anytime it wouldn't let you raise fully, it means there is stuck valve in the valve body not allowing fluid to move around.

Since you also have the old VB, you can also try connecting it in place of the new one just to see if things will improve or let you move the motor fully up. If it does, then there is a stuck valve in the new VB. Next step is to do the test procedures to identify the faulty component. And 90% of the time it is the spool valve o-rings being worn out. Remember, there is not need to disassemble the VB to replace these o rings or the o rings on the shuttle valve.

 

[Jiggz]

No Title

Here's a hydraulic diagram to have better understanding on how it works.

 

[davijc02]

Jiggz,

Do you have a tutorial guide on replacing both the O-Rings in the VB that your reference? I won't be able to look at it tonight, but would loved to be armed with knowledge for tomorrow morning if I get a chance.

Thanks again.

 

[Jiggz]

Have your read the link I posted earlier? If you read the entire thread there is a section in there by PNW on how to remove the spool valves, replacing the o ring on them and re-installing them. There is also a thread by SkiDad who posted pics of the whole scenario on how to replace the o rings. I wish I have an extra unit and take pics and annotate them on how to do it or maybe even a step by step youtube video

 

[Jiggz]

Here's the SkiDad thread to get you going:

http://forums.iboats.com/forum/engi...8857368-trim-leak-down-isolated-to-valve-body

 

[Frank Acampora]

Running the pump at full up for extended periods will do no harm but it will foam the oil making it difficult to impossible to operate until the air comes out of the oil. Usually sitting overnight will do.

 

[Frank Acampora]

If you have already removed the front valve body there is no need to loosen the hydraulic fittings. The rear valve body (which keeps the engine from rising manually is a little more difficult to remove, You have the option of loosening the engine on the transom or removing the pump to access it.

Running the motor in full up (or down) position for extended periods will not harm the pump. You do run the danger of over heating the motor and you will foam the oil, making it difficult to impossible to operate until the air bleeds out. Usually sitting overnight is sufficient.

 

[davijc02]

I went out this morning and loosened the fittings and have released the pressure that was trapped in the tilt cylinder. I can now move the motor by hand all the way up now. I have removed the valve body from the motor and will check for broken O-rings tomorrow morning.

 

[davijc02]

Update

I removed both bypass valves today to disassemble and look for broken O-rings. I front side cap was pressed into the housing quite tight like I assume it should be. I had to apply a lot of force using the automotive pliers as suggested which worked well. Once taken apart the spring looked good. Also, the o-ring on the hexagon shaped piece was intact and looked normal.

I removed the back bypass valve and instantly noticed that the top cap that is removed with the pliers was already halfway or more out from the housing. It separated from the housing with ease using the pliers. All parts inside looked normal with no signs of wear.

I also removed the shuttle valve and and inspected that O-ring which looked perfect as well.

I didn't have time before work to mount the valve body again to function test. But I assume that with the rear bypass valve not seated together correctly that probably was the reason the pump wasn't moving any fluid? Seems reasonable to me anyhow that it wasn't pressurizing.