Mercruiser AlphaOne trim problem

[bradyfehr]

The switch on the throttle control will drop the trim just fine. When I try to raise it sometimes it runs for 1 second then stops, other times it clicks, and other times it doesn't do anything.

So, after reading up about this in the these forums I replaced the 2 relays on the trim motor (they're cheap and replaced the 110v fuse which I destroyed taking it off). Results: no change.

I tested the trim motor by jumping 12v directly from the battery to the relays - trim goes down AND UP. Maybe a bad switch at the throttle? Disconnected the clip from the throttle control and jumped 12v directly into the connector - same problem (goes down, not up).

The only other thing I can think of is the limit switch on the drive itself? I know nothing about these, is it possible the "up" limit switch is bad? Is there such a thing as a "up" limit switch? Are there 2 switches - one for down and one for up?

I'm sure this is pretty common, maybe just direct me to the correct thread?

Thanks in advance.

 

[harringtondav]

Your drive has two senders. The trim gage on the right, and the trim limit on the left. The trim limit sender stops the 'up' travel before your out drive is too high to safely provide power. Sounds like your trim limit sender is failing, or out of adjustment. Crank your steering hard right. Then loosen the two clamp screws on the trim limit sender's hsg. and rotate the hsg. CCW and see if your out drive raises higher. If it does, adjust the sender until the extended length of the trim cyls. is 20 1/4" measured between the two pivot rods. If sender adjustments don't change anything, the sender is likely bad and needs replacement. You can sneak thru by disconnecting the sender leads inside the engine compartment, and jumping the engine harness leads. But be careful. This is a temp. fix to get you thru boating season. Applying too much throttle with the out drive too high could cost you more than a sender replacement. Use the cheat until the end of the season, and then replace the trim limit sender.

You can also cheat by using your 'trailer' switch to trim up, but the hazards to your out drive are still there.

 

[Bt Doctur]

jumper the limit switch at the pump. If trim up now works, the trim limit switch is bad

 

[Oshkosh1]

Pull the entire trim pump assembly. Much easier to work on OUT of the boat and on a bench. Secured to the deck by only four screws. Anyhoo...disassemble, clean, reassemble and ensure you have good grounds. My trim was acting strange and would sporadically act like yours. It was pretty dirty but cleaned up to almost "new" condition using some Super Clean and a Dremel with a wire brush. Haven't had an issue since. When you assemble it, don't use grease on the connections. Buy yourself some PVC "paint" AKA "liquid electrical tape" which is the same rubberized coating used from the OEM. Spray it, let it dry, hit it again. FWIW...I use it on all my marine electrical connections including the trailer lights when I converted it to LED.

 

[bradyfehr]

Pull the entire trim pump assembly. Much easier to work on OUT of the boat and on a bench. Secured to the deck by only four screws. Anyhoo...disassemble, clean, reassemble and ensure you have good grounds. My trim was acting strange and would sporadically act like yours. It was pretty dirty but cleaned up to almost "new" condition using some Super Clean and a Dremel with a wire brush. Haven't had an issue since. When you assemble it, don't use grease on the connections. Buy yourself some PVC "paint" AKA "liquid electrical tape" which is the same rubberized coating used from the OEM. Spray it, let it dry, hit it again. FWIW...I use it on all my marine electrical connections including the trailer lights when I converted it to LED.

That's exactly what I did, right down to the wire brushes and liquid tape, lol. Thanks!!