88 125 force tilt trim not working

Hello, I am new here and hope someone with the experience can help.

I have a 88 125 hp force with a 2 wire tilt and trim. I can hear my motor turning but the engine will not go up or down. I replaced the fluid in the resevoire and still no go. The engine is in down position and will not manually raise up. My question is, where do I start on trouble shooting this, is it something I can do or Should I take it to an expert. I would really like to do it myself to save some money for more boating but if need to I would like to have it done right. Any suggestions would help. Thank you.

Re: 88 125 force tilt trim not working

Is this something that just all of a sudden happened or has the boat been sitting for a long time?

Re: 88 125 force tilt trim not working

my dad has the same year 125 on his boat - it will go up very slowly and you have to coax it - i think it's a common issue. He just blocked it so it will fall down and rest about veritical when boating. Mine bleads some on the tilt part but seems ok now on trim (i tightened up a few things around the lines)

Re: 88 125 force tilt trim not working

thelmuth said:

Is this something that just all of a sudden happened or has the boat been sitting for a long time?

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It just happened, I replaced the prop and took it out to the lake for a test run. Ran fine, went to go trim and nothing. Can only hear the motor turning but no lift.

Re: 88 125 force tilt trim not working

Hmmm, I was thinking maybe the pivot point had corroded keeping it from moving but if it just happened I'm not sure. You said the fluid is full. Can you tilt the motor by hand while someone is operating the control? Is there possibly something blocking the motor from tilting? Just guessing now

Re: 88 125 force tilt trim not working

thelmuth said:

Hmmm, I was thinking maybe the pivot point had corroded keeping it from moving but if it just happened I'm not sure. You said the fluid is full. Can you tilt the motor by hand while someone is operating the control? Is there possibly something blocking the motor from tilting? Just guessing now

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No, i am not able to lift it while operating.. Tried it today. Also I noticed that the rear screw on the motor that go's into the resevoir housing to hold motor down was not tightening, seems to be stripped inside the housing. Wondering if this could be the issue by allowing air into the resevior. Going to try and get a screw one size up in diameter and see if i can re-thread to hold pump down.

Re: 88 125 force tilt trim not working

hydraulic lift is all about how many PSI are applied to how many square inches of piston and the geometry of your fulcrum. It is not uncommon on 3 ram systems for tilt to bleed off while trim still seems normal.

tilt has a very small piston on about 3" fulcrum. It needs 700-1000PSI to fully lift engines of 85HP and larger.

Trim on the other hand has about 10x more piston area on about an 11" fulcrum. It hardly needs any pressure at all to lift a dry engine. However, when the prop is spinning then pressure increases with horsepower. The 120 and 150HP Force can actually generate enough back pressure to impregnate the rubber if you use ATF fluid. If you have a 25" shaft engine then the back pressure is raised even further.

there is supposed to be air in reservoir. It compresses and decompresses as the system lowers and raises. Air bubbles in oil do not cause bleed down. The system is dual action and air tight. The air is trapped in place until it gets back into reservoir - where it floats harmlessly to the top. Being low on fluid causes the system to stop lifting. The real issue with low fluid is not the fluid as much as finding the leak. If oil can get out then water can get in.

Re: 88 125 force tilt trim not working

RRitt said:

hydraulic lift is all about how many PSI are applied to how many square inches of piston and the geometry of your fulcrum. It is not uncommon on 3 ram systems for tilt to bleed off while trim still seems normal.

tilt has a very small piston on about 3" fulcrum. It needs 700-1000PSI to fully lift engines of 85HP and larger.

Trim on the other hand has about 10x more piston area on about an 11" fulcrum. It hardly needs any pressure at all to lift a dry engine. However, when the prop is spinning then pressure increases with horsepower. The 120 and 150HP Force can actually generate enough back pressure to impregnate the rubber if you use ATF fluid. If you have a 25" shaft engine then the back pressure is raised even further.

there is supposed to be air in reservoir. It compresses and decompresses as the system lowers and raises. Air bubbles in oil do not cause bleed down. The system is dual action and air tight. The air is trapped in place until it gets back into reservoir - where it floats harmlessly to the top. Being low on fluid causes the system to stop lifting. The real issue with low fluid is not the fluid as much as finding the leak. If oil can get out then water can get in.

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Ok, glad to know. I was assuming that if it did not seal properly "like a master cylinder" then it would act like a master cylinder when trying to stop a vehical with air trapped in the brake system. Anyway, I took apart the motor and cleaned everything inside with low grit watered down sand paper. I put it all back together and the motor sounds better than ever when turning. The M-cylinder started moving a little but motor still would not go up.

If it isn't air, then what would you suggest it was? I flushed out all the lines and replace with #30w ND Motor Oil.

Re: 88 125 force tilt trim not working

dwhis said:

Ok, glad to know. I was assuming that if it did not seal properly "like a master cylinder" then it would act like a master cylinder when trying to stop a vehical with air trapped in the brake system. Anyway, I took apart the motor and cleaned everything inside with low grit watered down sand paper. I put it all back together and the motor sounds better than ever when turning. The M-cylinder started moving a little but motor still would not go up.

If it isn't air, then what would you suggest it was? I flushed out all the lines and replace with #30w ND Motor Oil.

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I would suggest that the rubber in most trim systems wears out between 18 and 23 years of age. you got 25. It's time to renew. The valve body is not DIY friendly and only brave mechanics should go there. The chrysler force rams are actually a much better than average device. Look at the topseals where piston shafts go in and out. rebuild the rams when those start to crack, harden, chip, or lift out. Internally the force rams can go 30+ years but once they start letting water and oil past the top seals then you have a potentially fatal problem.

Re: 88 125 force tilt trim not working

RRitt said:

I would suggest that the rubber in most trim systems wears out between 18 and 23 years of age. you got 25. It's time to renew. The valve body is not DIY friendly and only brave mechanics should go there. The chrysler force rams are actually a much better than average device. Look at the topseals where piston shafts go in and out. rebuild the rams when those start to crack, harden, chip, or lift out. Internally the force rams can go 30+ years but once they start letting water and oil past the top seals then you have a potentially fatal problem.

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Well the good news is I am very familiar with rebuilding brake calipers and am not itimidated at all opening this unit up. Found a few schematics online that help. The bad news is that when i was removing the hydraulic "down trim" line, well the flare ring snapped. Looked online and they run between 40-50 dollars and only if available since this part is now obsolete. I was thinking of going to a hydraulic supply store and just picking up a tube and flare. Is there a specific typ that you would recommend? You seem to know this unit really well and know how to explain it in detail.

Re: 88 125 force tilt trim not working

if the port is stripped then you're in trouble. behind the ports, inside the fluid channels, there is a recess that can collect metal shavings. you can fix the threads with a brass 1/8" male pipe to 3/16" female inverted flare adapter. they probably have those at NAPA. The bad news is that it is not a good idea to drill and tap the hole for 1/8" pipe without taking VB apart and flushing out metal flakes. it is not a job for a duct tape or corner cutting mechanic.

as regards the tube, if you DIY then you want brass tube nuts on CuNi tubing. Pure copper or AL is not strong enough and will eventually burst. CuNi actually came from commercial/industrial/military marine and was not availiable under 1/2" diameter for longest time. Now, it is also used on Mercedes and Volvo in the size you need (because it won't rot from road salt).

I'm fairly sure I have a set of tubes in the bottom of my 50gallon orphan & widow tub. If you give it a good effort and can't find any then I could go dig around for them.

Re: 88 125 force tilt trim not working

no, thankfully the port did not strip. going to do a double flare to the line and re-cap it. I would replace it but I'm having trouble removing the lower brace bolt that removes the trim housing. seems that the bolt is too long to take out, keeps hitting the side of the boat. looks like the only way is to either cut it, or remove the transom mount.

Force 125hp Tilt Leaking Down / Not Working
Should be same procedure for 1985 to 1998 60hp to 125hp

First of all! Don’t waste your money on the cheep o-ring rebuild kit! The $10.00 one is crap, spend a little money on a good kit

Repairing the Tilt Ram

1) After you take the Ram apart, you have to get a break cylinder hone (About $20.00 at your local auto part store) and clean up any scratches in the Cylinder walls

2) Replace all the o-rings and seals

3) Before you put the ram back together put a little grease on the cylinder threads and o-ring

4) Gently rock the plunger into the cylinder while applying lite pressure (this will stop o-ring damage) DO NOT USE A HAMMER, EVER!!

5) once it is back together, if it still leaked down or does not work,? You may have damaged the interior cylinder o-ring or the valve body on the pump is bad and must be replaced.

If you take your time and do it right, this repair should last a long time, Good Luck, Hope This Helps
(Hone)

(Valve Body)

My tilt trim was doing exactly the same thing as yours. You can coax it up but bleeds off internally. I bought a new pump assembly complete for 150 bones and it now works perfectly. When I removed mine there was alot of metal shaving paste around the top of pump. I suggest you use some ultra black permatex when replacing around the new oring and ensure your 4 screws securing the pump are in good shape or you can join me in doing things twice!!

Inital repair is the 2 seals bottom next to the shuttle.
99% of the time they have gone bad.
Post #4 in this forum has a bunch of posts that cover this and more.
The 2 posts below cover a lot with the shuttle valve repair and T@T fixes.
I wouldn't replace/rebuild anything until the links below have been checked out.