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Trim up doesn't work when underway

H

holinwtr

Regular Contributor
I have a '76 Somerset, 165 L6, #1 drive. I just replaced the trim limit and trim sender switches. Those are working good. I installed an aftermarket pump about 5 years ago. I have never been able to trim the drive when the boat is moving with any speed. With the new pump I got rid of the reverse lock switch. It's supposed to have an internal reverse lock. It also accepted the 3 prong plug that plugged into the original pump, so there was no re-wiring to speak of. Any ideas on why it won't trim up when underway. It will trim down when underway but that is the way the prop wants to push it so that doesn't surprise me. Also, I tried switching the hydraulic hoses around and that didn't work.
Thanks
 
Trim limit switch may not be set correctly. It will stop the up movement of the OD once the limit switch is engaged. If the trailer switch will move the OD up then the Trim limit switch adjustment is the issue.
 
The trim limit switch is working correctly. In the up position it measures the correct 21-3/4" from bolt to bolt. Even when I push both "up" and "out" buttons it still won't raise the drive when the boat is moving with any kind of speed. Could it be that the hydraulic hoses are switched backwards where they go from 2 hosed to 4 hoses underneath the gimbal? Because it does seam like the pump is generating more power when lowering the drive as opposed to raising it. As I said, I tried switching the hoses at the pump and that didn't work?
 
Could it be that the hydraulic hoses are switched backwards where they go from 2 hosed to 4 hoses underneath the gimbal?
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Did someone mess with them?

Because it does seam like the pump is generating more power when lowering the drive as opposed to raising it. As I said, I tried switching the hoses at the pump and that didn't work
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Did you connect the hoses correctly? It takes more pressure to raise the drive vs. lowering it.

I installed an aftermarket pump about 5 years ago.
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Did the change include a new valve body?

I have never been able to trim the drive when the boat is moving with any speed.
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Valvebody not working.
 
After I thought about it switching the hoses would not work because then hitting the down button would raise it and vice versa. The new pump came as a whole unit. It was plug and play. It works alot better than the old style pump in that its a lot faster. There has to be some reason why it won't raise the drive when under a load. Switching the hoses at the pump did not work. It would barely move the drive in either direction under no load and the down button raised the drive and vice versa. The new pump was already wired when it came so like I said, all I had to do was plug it in and go. Maybe if I switched the blue and green wires AND switched the hoses it would work.
 
Does the pump assy. sit over a white plastic or black metal reservior? The black reservior requires the fluid fill screw be opened 3/4 turn to vent it.
 
Guy, the unit has a white plastic resevoir. gl115, ya all the air is out of the system. Here is a pic
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Under load does not mean a hole lot.

I think what you need to do is try raising and lowering the drive when out of the water, with the shifter in forward and reverse.....

If you left the hydraulic hoses connected as original then you may be locking out the hydraulics even though the pump is running.

Also on the old systems they used 20 weight oil NOT power sterring fluid..........
The pump you purchased it Not exactly a plug and play. The older systems are NOT the same as the newer systems.
Differnt pressures, different oil weights etc. The older unit may have been a high pressure low volume where as the newer one may be high volume lower pressure.

Unfortunatley I am not an expert on the inner workings of the trim systems but I do remember some things are different.

Just a different prospective.


didnt your configuration have a mechanical switch for trim limit on the shift bracket at the rear of the motor?

Really not sure what your issue is exactly. if it works when on land trimming up it should work easier on water as the water flow/force should push it up with little or no effort.
 
As usual, kghost's experience confirmed one of my suspicions. Since the new A/M assy. has not worked since day one my thoughts are threefold: wrong pump assy., defective valve body up circuit or old up hose deteriorated internally blocking fluid flow. I doubt it is an air bleed issue since the pump style is a self bleed type. The Boat Dr. may have the answer.
 
Thanks for the replies fellas. Kghost, the pump will raise and lower the drive with it in gear. In fact it will even raise and lower when the boat is idling in the water. It's only when the boat gets above, say 10 knots before the pump will no longer raise it. I don't know if the pump is defective or not. I do know it raises and lowers the drive perfectly other than it won't do it under load. I have 5-20 weight oil in it as per specs. I've lived with it like this for 5 years so I'm not too worried about it. Thanks for the replies
 
Ok that clears up a lot
BUT. I want to know if you move the throttle to approx where it would be when this occurs (on the trailer with the motor off then running in gear ).

Does the drive still work correctly?

You did not say if you took the reverse hydraulic lock out out of the plumbing...
What you describe is really not possible unless there is a lock out of some kind.
 
As I said in my first post, with the new pump, the old reverse lock is not needed. The new pump has internal reverse lock. On the trailer it doesn't matter where the throttle is, the pump works like its supposed to with the motor on or not.
 
OK

So you are saying that the new pump is plumbed directly to the trim rams? telling me the reverse lock out is not needed does not tell me you removed it from the hydraulic circut.....it only tells me you understand the new pump has it internal.


The trim sender and trim limit wiring is now the same as a newer boat configuration and is not going thru any old switches on the shift cable brackets?

Well this is what I would do next.

Take the trim limit switch out of the equation.

Also have someone with some wieght say 250 lbs or more stand on the drive and see if the pump and pistions (trim cyclinders) will raise the drive with a heavy load on them. A working system should lift 300+ lbs no problems.

Again this makes no sense, as the boat moves forward the natural tendency would be for the drive to KICK out or up.

The reverse lock out keeps the drive from kicking out when in reverse. I have seen many without this and it is scary.

You have a three button control in the dash correct?

Please explain how you use the buttons under normal use, down, trim, and trailer positions. WHich buttons for what and what combination and for what fuction.

If you have never replaced those push buttons maybe the issue is there?????

Have you tried with the use of a good jumper wire and jump the up solenoid while under way when the drive wont trim up and bypass all controls?

Go from battey + directly to the (small blue wire) on the solenoid (not the large blue wire). This will energize the up solenoid and the trim pump motor in the UP direction.

The old style system also used a ONE solenoid trim pump (UP). Was yous this way? The down function was direct to the trim motor and no solenoid was uses. (HIGH CURRENT) not very efficient......and succeptable to fire!!!


Maybe we can figure this out with a few better questions ans answers..........
 
After researching my own problem, and getting a better understanding, one thing comes to mind that hasn't been mentioned yet:
The two different operating pressures (High pressure (2600#) to raise the drive, low pressure (500#) to lower the drive) are controlled by the relief valves internal to the pump assembly. If the relief valve on the high pressure side is not set properly, it could be limiting the pressure to the rams on the up stroke. This would explain why it works fine, except when the boat is moving forward with a little bit of speed as mentioned.
Unfortunately, the only way to really get an idea of what pressure the pump is producing is to hook up a test gage. Merc provides a test gage specifically for this (91-52915A6), but it runs about $500. Otherwise, you might want to buy a new up pressure relief valve (812498A1) ($60) and swap it out and see if that gets it.
 
One more thought occured to me. If the wiring was somehow backwards, and the hoses were also swapped, this could also explain what you're experiencing. (i.e., the low pressure side is being used for raising instead of the high pressure side)
Hard to tell what the boat wiring colors would be, but on the three prong plug connected to the to the pump soleniods, there should be a red/purple wire (fused power to the helm switch), a blue/white wire (power return from the helm through the trim up limit switch for raising) and a green/white wire (power return from the helm switch for lowering).
With the drive fully lowered, hook up a 12V test lamp or test meter (on DC volts), one side to ground the other on the terminal the blue/white wire is connected to on the pump soleniod. Push the trim up button on the helm switch. If the test lamp lights or 12v is indicated on you meter, it's wired correctly and if the drive goes up, you can assume the plumbing is also correct.
If it doesn't light (or indicate 12v), push the trim down button. If it lights (or indicates 12v) it's wired backwards and the hoses are backwards.
If this test shows the wiring to be incorrect, swap the blue/white and green/white wires on the soleniod terminals and swap the two hoses coming out of the pump housing.
 
Ghost, the outdrive won't raise when the boat is moving because the force of the propeller is pushing it forward. The new pump is connected straight to the trim rams now. No external reverse lock. I do have the three button control at the helm. I lower it with the down button. I trim it up with the middle botton (up). And I raise it up all the way with the middle and top button (up) and (out). I have not tried to bypass the controls yet but I will have to do that. Troy, I also thought about the wires and the hydraulic hoses being backwards becuase it does seem as though it has more power and umph when it lowers. Raising the drive does take longer than lowering it but I always thought it was because of gravity helping it. I will try to work on it this weekend between kids soccer games and honey do lists. Thanks so much for the help guys.
 
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holinwtr:

Please don't try to adjust any of the settings on the valve body. They are factory set and if you mess with them you'll never get them reset correctly. Unless you did some Gomer Pyle rewiring the wiring should be correct. Have you swapped the hoses on the pump?
 
Don't worry guy, I won't try anything stupid:). I didn't re-wire anything, that's what's so confusing. Yes I tried swapping hoses on the pump, but then down button raises the drive and up button lowers the drive. Maybe along the way somebody rewired the helm switch wrong. I'll check it out this weekend.
 
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holinwtr said:
Don't worry guy, I won't try anything stupid:). I didn't re-wire anything, that's what's so confusing. Yes I tried swapping hoses on the pump, but then down button raises the drive and up button lowers the drive. Maybe along the way somebody rewired the helm switch wrong. I'll check it out this weekend.
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Ayuh,... At the pump, the wiring is Green(grass) Down, 'n Blue(sky) Up...
 
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