Trim pump won't trim out/up... occassionally

[hal2814]

I have a 1990 Mercruiser Alpha One Gen I outdrive with the Oildyne trim pump and plastic reservoir. When I try to trim up, sometimes it works and sometimes it doesn't. When it doesn't work, I hear a grunt and then nothing. I then usually have to press trim up about 5 to 8 more times and it will kick in. Fluid is filled to proper levels and the oil itself looks good. I'm looking at the manual page for troubleshooting the trim system now and there are 12 items. I was wondering if any of them could be eliminated since the trim does work at least 3/4 of the time. If not, I'll run through them all but some of them look pretty involved and if there's a common culprit in this situation, I'd like to test that first.

EDIT: Oh and by "manual" I mean the proper Mercruiser service manual pdf that has been so graciously passed around here.

 

[HT32BSX115]

Re: Trim pump won't trim out/up... occassionally

Howdy,

Have you had it apart and seen if the filters are either plugged or disintegrated? This wouldn't make it intermittent but it's a good place to start. Intermittent operation is usually electrical. Tilt/Trim switches, solenoids, motor. Your problem sounds pretty much electrical since you need to press the button multiple time times to get it to work.

The trim motor is a fairly high current device. Electromagnetic solenoids are used to switch the current on and off to the motor (not un-like your starter solenoid)

Those solenoids sometimes go bad. There's another set of switches either on the dash or in your throttle that control the solenoids. If they've gotten wet and are a little corroded they won't close when needed to actuate the solenoids.

Those Boatfix online manuals should have schematics of the circuit, color coding of the wires etc.

Also, if you have a trim limit switch it's possible for it to be corroded a little and preventing the trim from going up intermittently. It should be only wired in the up circuit. It won't prevent the drive from going down.


Regards,



Rick

 

[Spike2450]

Re: Trim pump won't trim out/up... occassionally

Hi i'm not sure if this all relates to you as i have a 1998 Alpha one.

Had - infact still have a similar problem with mine.

The outdrive would always trim down fine but would have erratic trimming up on the switch and the trailer switch.
The Up Solenoid has been changed, now the trailer switch always works fine but the up trim switch is still erratic.
So must be the switch itself or more likely the Trim limit sender switch located on the port side of the outdrive leg, these tend to go bad, to change means removing the bell housing. I'm going to leave mine untill the end of the season.
Apparently it is quite common and a lot of boaters will use the trailer switch only but you have to be careful when using the trailer switch that you don't bring it up to high when you are running.

 

[hal2814]

Re: Trim pump won't trim out/up... occassionally

Electrical sounded like a good place to start so I started at the battery. I had two sets of wires running to the battery itself. On my last boat, one set was the bilge pump and the other was the rest of the system. I disconnected both sets of wire and hooked up the main lines to the battery. Nothing on the trim. Turns out on this boat, that second set of wires goes to the trim pump. Is that normal? Shouldn't I have some sort of fuse between the trim pump and battery? At any rate, that second set of wires was pretty corroded so I cleaned them off and attached them to the battery. I haven't had the trim issue since. It was intermittent in the first place so that might not really have solved the problem, but so far so good. Thanks for the help.

 

[Rusty Boater]

Re: Trim pump won't trim out/up... occassionally

Had the same problem with my 1999 Alpha One. Take the cover off the limit switch and pull the plate that has the copper connections. Sand with 600 and the contacts as well. rub on some grease and reassemble. No problems for me since i did this. You do not have to pull the drive to do this.