Filling your tilt trim motor on a Chrysler

[MickLovin]

Hi guys, I can't see in my manual how it says to fill my tilt trim motor, I was under the impression you fill it when the motor is tilted up, but after reading a thread about a problem with a tilt trim, Jerryjerry advised that it is to be done lowered , can anyone tell me which is the best way to fill, at the moment I fill in the up position and drop it down and up a few times and then check if it needs topping up, if it runs out of the hole I tend to think it is full, but in saying all that I had a slight problem trying to tilt in the water, it was fine at the ramp etc, it was just not tilting up when I was running, I had to slow tilt up then go again, but the motor drops a bit. I have a kit for it but I see no leaks.

 

[jerryjerry05]

Re: Filling your tilt trim motor on a Chrysler

The Prestolite needs to be filled while down.
The newer Merc stuff needs to be up.
If you can't get it to tilt while running?
Then it needs oil or it needs rebuilt.
The leak can be on the inside and not seen.
Pic of your unit so we know exactly what you have.
There were some aftermarket units and some jury rigged stuff used over the years.

 

[MickLovin]

Re: Filling your tilt trim motor on a Chrysler

Sorry mate I don't have a picture. but it is the typical chrysler tilt trim motor, yea it didn't want to come up while i was on plane. But I will now fill it while down and maybe that will make a difference, I do have a kit but just a big job while my back and neck are buggered.

 

[Frank Acampora]

Re: Filling your tilt trim motor on a Chrysler

Looking at a prior post photo, you have the older three wire tilt/trim. Yeah, the manual says something about position to fill but my experience with these is that they are not fussy. You can fill in any position. Just be aware that after filling, you need to cycle the unit to extremes a couple of times to bleed out air trapped in the cylinders.

Also be aware that there may be some pressure built up in the reservoir so you don't want to open the fill plug with the engine in tilted up position.

 

[RRitt]

Re: Filling your tilt trim motor on a Chrysler

the photo did not come through on my browser ... but ...

Most prestolites are best topped off when halfway raised. This is a compromise between having a large fluid reserve and accidentally getting sprayed with oil. The system is self bleeding. You just lift and lower repeatedly. Each cycle pushes the air bubbles through the system. When they reach reservoir then they float to the top and your system is bled. After 3-4 full cycles (with checking/topping fluid level) there won't be any air left in system.

lifting/lowering problems have four causes, none of which are fluid level. If you fluid is low then your systems works perfectly up to a point. The point where it runs out of fluid. It won't lift past that point whether you are on a trailer, in a garage, or on a lake.

If it bleeds down slowly >> it is probably a check valve.
If it lifts on trailer and does not bleed down but drops under power >> your pressure regulator is probably malfunctioning.
If it is 1992-1995 and barely lifts at all then falls rapidly >> it probably had ATF from factory and your trim piston oring crystallized and split.
If it is 1972-1990 and barely lifts at all then falls rapidly >> it probably got water inside and rusted out your tilt piston bypass valve.

 

[MickLovin]

Re: Filling your tilt trim motor on a Chrysler

Ok, after refilling it at the lowered position I was unable to fill any more than when it was in the raised position, also after raising and lowering a half dozen times I noticed the noise I had of like a little popping, squelching sound here and there has gone. So if under power it lowers, if it is possibly the pressure regulator, where is the pressure regulator , in the valve body?? Truly I believe it is possibly leaking in the tilt cylinder but there is no sign of oil so it is internal, also it doesn't slowly lower at all but just won't raise up when on plane.

 

[Frank Acampora]

Re: Filling your tilt trim motor on a Chrysler

Do you mean raise up as in tilt out of the water or simply adjust trim?

Trim will only move the engine a couple of inches and then (on the trailer or at rest) tilt takes over. The tilt cylinder does not have enough hydraulic and mechanical advantage to raise the engine under power. In fact, there are relief valves built into the tilt cylinder so if you go much above 1000-1200 RPM in forward gear, with the engine tilted up and the prop still in the water, the engine will lower back down onto the trim ram.

That motor should have a built-in bimetal thermo switch. If you keep trying to raise the engine under power, the switch may open and you will need to wait until the motor cools down to operate tilt/trim again.

 

[MickLovin]

Re: Filling your tilt trim motor on a Chrysler

Adjust trim while planing, I have been able to trim my other 75's on the plane this one doesn't seem to move much, but I am glad I checked it all out because my top screw in motor mounts were loose. Love this preventative maintenance and restore, you learn so much.

 

[Frank Acampora]

Re: Filling your tilt trim motor on a Chrysler

Well, then you need to remove the valve body and replace it with one from a functioning unit. Then you need to disassemble the valve body at your leisure. Look for worn pump body and gears, worn check valve seats, and a loose pressure regulator. That is a screw and nut on the top of the valve body. If it is set too loose, then under load it will simply bypass fluid instead of moving the trim piston.

 

[MickLovin]

Re: Filling your tilt trim motor on a Chrysler

:mmph: looks like a bit of investigatory work, I will look at one of my already disassembled valve bodies and see if it is ok to change out so I can look at the one on the boat. I will be a genius by the end of my life with this outboard