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TiltTrim Pump failed on 30 Alpha One

audad

New member
"Help, please... My 1990 3.0 4

"Help, please... My 1990 3.0 4-cyl Alpha One tilt/trim stopped at the end of last summer. I did not repair it over the winter, as I should have! A mechanic just diagnosed it but he does not have time to fix it before end of July. He said the cylinders are good but the pump is bad. It would trim down weakly and trim up very, very slowly. After we talked about it, I said I'd try to install a new pump myself (with his blessing - he is a good guy) so that the boat might be ready sooner. Well, I installed the new pump today. It worked briefly both up and down for only a few minutes (except the up/down wires were reversed - easy fix), then it started sounding slower and slower in down direction only. Press up and the motor runs fine. Finally the down quit working altogether. I can just hear the slight click of what I'm guessing is the solenoid switch.
I'm going to put the old pump back in tomorrow to see if it still runs in both directions. That should at least check the switches. Any other suggestions would be most welcome. I am at a loss here."
 
"You have a worn solenoid. Pr

"You have a worn solenoid. Prove it by CAREFULLY shorting the two large studs on top of it. If it works the replace both solenoids as a pair.

Read the last 3-4 paragraphs.

How the trim/tilt works

Before you tear anything apart or replace wiring and switches, test it out; first by visual inspection by pulling back and forth on the wires while operating the switches and then test with a meter. At the commander switches, the red wire will always have 12 volts. The green wire gets 12 volts when the trim toggle is held down. The blue wire gets 12 volts only when the toggle is held up or the trailer switch is pushed in. The purple wire is part of the limit switch circuit.

If the switch voltages are as they are supposed to be then go to the trim/tilt pump assy. and make sure the purple wire connector (single wire) and the blue wire connector with two blue wires on one side of the connection are not corroded or loose. These are the trim position and limit switch wires. Pull them apart and inspect; they should be clean and tight; reconnect them. If necessary, trace the wires to the front of the engine near the slave solenoid. One wire is grounded near there and the other is connected to a terminal. If you don't get a voltage reading at the terminal junction, apply 12 VDC to see if the trim gauge moves. If it does, check for voltage back at the trim pump connections. If no voltage is there, apply 12 VDC there to check gauge movement.

Next check the three wire connector (RED, BLUE & GREEN) at the pump assy. This plug can vibrate loose and cause your problem. Pull it off and see if the pins are clean and not corroded; reconnect it.

The RED wire in the plug sends 12 volts from the pump assy. to the toggle up/down and trailer up switches. The BLUE & GREEN wires bring 12 volts from the toggle trim/tilt and trailer switches to the two solenoids on the pump assy.

The GREEN wire goes to the DOWN solenoid while the BLUE wire goes to the UP solenoid.

Did you check the switches with an ohmmeter? The trim/tilt switch is a 2-way switch and will show continuity only when it is toggled in each direction between two of the wires.

Up toggle connects the RED wire to the BLUE wire. Down toggle connects the RED wire to the GREEN wire. The TRAILER UP switch also connects the RED wire to the BLUE wire.

The OD trim limit switch will only send voltage to the trim/tilt switch in the upward toggle position if the OD limit switch is below the adjusted trim limit that keeps the OD being out of the water.

To test the limit switch circuit, lower the OD to the down position and slowly raise it with the trim toggle up until it stops. Then measure the distance between the trim cylinder attaching bolts. If the distance is approx. 22 +/- 1/4 inches, then the trim limit switch is adjusted properly and the commander trim toggle switch is working in the up/down mode.

Go to the trim/tilt pump assy. and make sure the purple wire connector (single wire) and the blue wire connector two blue wires on one side of the connection are not corroded or loose. Pull them apart; they should be clean and tight; reconnect them.
Next check the three (RED, BLUE & GREEN) wire connector at the pump assy. The RED wire in the plug sends 12 volts from the pump assy. to the toggle up/down and trailer up switches. This plug can vibrate loose and cause your problem. Pull it off and see if the pins are clean and not corroded; reconnect it.

The BLUE & GREEN wires bring 12 volts from the switches to the two solenoids on the pump assy. The GREEN wire goes to the DOWN solenoid while the BLUE wire goes to the UP solenoid.

Disconnect the trim/tilt assy. wires from the battery and then check each of the nuts and studs on the solenoids for clean and tight fittings. Each solenoid has three wires and the buss bar connected to it. The bases of them have a black ground wire and a small blue wire to one and a small green wire to the other.

On top of each solenoid, the large BLUE wire from the pump motor attaches to a large copper stud with the solenoid that has the small blue wire at the base while the large GREEN wire from the pump motor attaches to a large copper stud with the solenoid that has the small green wire at the base.

The other copper solenoid studs are connected together with a copper buss bar. One of the two studs will also have a funny looking 110 amp fuse attached to the bar. The large RED wire from the battery connects to the 110 amp fuse. This large red wire is the power for this buss bar. A small RED wire attached to the bar stud sends 12 volts to the switches which in turn sends the 12 volts to the solenoids which turns on the pump motor.

Important: if the studs on the either solenoid are dark and not like a clean penny, especially the BLUE wired solenoid, this solenoid is failing due to age and/or a loose bottom copper stud nut. The dark color comes from heat generated inside of the solenoid by the contactor because it is arcing like welding similar to points wearing out. Change the solenoid.

Cleaning Trim Limit Switch & Trim Position Sender

For the trim/tilt problem you are experiencing, if the wires from the limit switch (port side) and trim position sender (starboard side) are in good condition, they (Switch or sender) can be disassembled to clean out the old hardened grease. SCRIBE the sides of each one and the OD for a reference mark before removal. Clean out the old grease and pump fresh Mercruiser 2-4-C grease thru the zerk fittings before reinstallation. Clean the small brass contact points with solvent and a pencil eraser until shiny; repack w/ 2-4-C grease and reinstall by aligning reference marks."
 
"Thank you sir!
OK, I obvious


"Thank you sir!
OK, I obviously have some work to do. I must first admit that I am not "electronically savvy." I do have a small volt meter, so I can check current with that.

It also has a ohmmeter setting, so I can test the wires. Which wires do I connect for ohm testing while operating the switch? UP=RED+BLUE then DOWN=RED+GREEN or connect BLUE+GREEN for both UP and DOWN? What should the ohmmeter reading be?

My boat (1990 Wellcraft 170 Classic) does not have a trim gauge on the dash. I don't think it has the trim limit switch &/or trim position sensor, either. I haven't seen any purple wires, but will check again when I get back to work on it.

If I loosen the fittings at the base of the drive unit and drain some fluid (10W30 as per manual) out, the unit will lower. The down switch still just makes a click, no pump engagement, while the up switch will operate and pump the unit back up. Strangley, this is NOT the original problem. On the old pump, it would work both directions but just couldn't generate enough pressure to raise the unit except at a very very slow rate. Thus, the solenoid must have worked at that time?

Thanks for your advice!
Drew"
 
Do you realize that you need a

Do you realize that you need a good fully charged battery to perform testing w/the motor? A weak low voltage battery will cause a solenoid to just click and a motor on the pump assy. to slow down.

Get a fully charged battery and run the up/down test. To use an ohmmeter you have to deisconnect the battery. Put the meter on the 500 ohm or 1k ohm setting and hold on the wires listed and test the switch up/down for continuity. It should show "0" ohms. Anything else it's a bad switch.
 
"Thanks! I appreciate your adv

"Thanks! I appreciate your advice.
Should be able to work on it tonight or Saturday. I will check the battery first, too."
 
"Update... The down solenoid w

"Update... The down solenoid was also faulty, which was an easy replacement. Thanks again for the advice! While I could not get the job finished by July 4 weekend, we are hoping to use the boat this Saturday.

This boat is certainly a "work in progress" so I will continue to use and appreciate the info on this forum! The really big project (a winter job) will be removing and replacing the wood decking (yuk) and replacing the carpet, followed by rebuilding and reupholstering the seats.
Best Wishes,
Drew"
 
Contact me when you do your de

Contact me when you do your deckwork. I'll pass on some ideas I used when I replaced all the wood in my boat.
 
"Thanks Guy,

I know this sh


"Thanks Guy,

I know this should go to a new topic outside of Mercruiser, but I appreciate any advice! I did this job about 10 years ago on a 15-ft 1977 SportCraft trihull and it was not much fun. I swore I'd never do it again, but maybe the second time around will be better. The Wellcraft is a boat I'd like to keep, so it's got to be done and I can't afford to pay someone else for the labor."
 
"For the floors I used exterio

"For the floors I used exterior plywood w/1 side sanded. I cut it to fit w/beveled edges and made sure the floor had a 1" slope toward the center of the floor for drainage.

Then I treated it w/2 coats of CPES (Clear Penetrating Epoxy Sealant); extra on the ends and sides. I screwed it to the stringers w/SS wood screws. For each screw I squirted a 1/2 tsp. of CPES and drove in the screw; it drew the CPES into the wood with it. Mix CPES in an liquid dish washing detergent bottle; it will stay fresh several days.

Lastly, I laid two layers of 20 oz. F'glass in epoxy over the floor."
 
For what it's worth Drew I

For what it's worth Drew I had a good friend of mine replace a transom on a 16' Reinell tri-hull and he said he would rather do 20 new floors then do a transom again. It's all relative.
 
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