TROUBLE SHOOTING MERCRUISER POWER TRIM #1 AND ALPHA GEN I
1) If your trim doesn't work there are several possibilities. You must divide these into groups.
2) The first thing is to find the section of the problem.
3) Push the up or down trim button. What happens 1) nothing 2) click 3) motor strain noise 4) motor freewheeling noise.
4) If nothing happens, you must check the motor. With a heavy #10 wire from the battery positive touch the end of either the blue or green wires which come out of the elec motor. If the motor does nothing and the wire doesn't spark when touching the leads the motor is bad. before replacing it however touch the wire lightly on the ground wire and expect a heavy spark. If the wire doesn't spark the ground connection is bad, fix it and recheck.
5) A click usually means a bad solenoid. To check the solenoid after the ground wire is checked, jump the two larger terminals on both the blue (up) and green (dn) solenoids. If they both operate the motor but jumping from the 12+ large terminal to the small green or blue terminal gives only a click or nothing the solenoid must be changed.
6) A freewheeling motor sound indicates low oil or a leak between high (up) pressure and low (down) pressure. Ck oil level in reservoir.
7) A straining sound means a restriction or stuck ram / cylinder. remove the two hoses on one side and see if the strain is gone
8) If the strain does not go away try taking the hoses off of the pump and recheck, if it goes away the problem is in the hoses or reverse lock out valve.
9) If the motor checks good but the buttons don't work jump a small wire across the plug holes where the harness from the switches plug in. Across one pair nothing will happen, one pair will go up, and one pair will go down. If this works but the buttons don't the harness or buttons are bad. Try jumping from the red wire by the buttons to the green or blue at the buttons, this will make it easy to tell which is bad.
10) If the unit goes up but will not go down or goes slow this usually indicates a sticking ram.
11) If the unit leaks down either slowly overnight or fast enough to see, this indicates either a high to low pressure leak in the rams or a bad control valve. Most new rams or ram shells come with two plugs in the threaded holes to prevent paint from getting in the threads. Most mercruiser dealers could borrow a pair to lend you or give them to you in as much as they are packing and throw away plugs. Trim the unit to the top and block it up with something, remove the two hoses from one side ram and plug the holes then remove the block and let the unit fall. If the ram is not leaking the unit will stay up. Repeat this test on the other side. If both rams keep the unit up the control valve on the pump is defective. Mercruiser sells them and the 'o' rings above them which are necessary to repair.
12) Another frequent problem for prestolite type pumps is "they work fine unless you jam them to the top where they stick and will not lower. loosen one hose on the up side will let it fall just slightly after which it will work fine until jammed again. If you do not hit the top it will operate fine. This indicates a bad control valve.
13) Some Oildine pumps run fine but produce no pressure. If you remove the tank exposing the valves and sump screen and put a small cup of oil under the sump and hit the buttons up or down, you may see the tube valves pouring out oil. this is wrong because if it comes out there it will not go out the hoses. The valve may be removed and changed but it should be checked with a pressure gauge before reinstalling the pump in the boat. Some people loosen the lock nut on the bad valve without changing its location and remove the tube valve from the pump and try to clean the ball, spring, and seat. but if the nut is lowered the tube will screw in further and raise the pump pressure. We can not recommend this therefore without caution and without a pump pressure check afterwards by a professional.
14) If the rams move funny or wrong two hoses may be swapped. As a rule the two hoses that come out of the plate closer to the transom are high (UP) and should go in the holes in the rams closer to the transom, however if you have problems try plugging one side off an the hose manifold and work only one ram. if it goes the wrong way something is wrong. The first check with the hoses off does the hole closer to the transom spit oil with the up button, this will tell you if the pump is pumping wrong or the hoses are crossed.
15) We sell trim cylinders, repair kits, 'o' ring kits, motors, pumps, and ram pins
