1990 Mercruiser Alpha 1 - Power trim goes up, down only works sometimes

[z0lt3c]

Hey Guys-

Just de-winterized my 1990 Larson 170BR w/ Mercruiser 4cyl inboard & Alpha 1 outdrive. During my systems check I noticed a problem w/ the power trim adjustment;

The outdrive will go up quite reliably, either by way of the up position on the trim switch or the trailer button. However, the outdrive will only go down quite infrequently, maybe 10% of the time. When it doesn't go down, I do always hear the down solenoid click, but most of the time the outdrive does not move in that direction.

For some reason, if I tap the trailer button and then hit the down trim switch, it works more frequently, maybe 70% of the time, but it is still not what I consider reliable operation. Here are my assumptions;

1) Hydraulic pump is working since it operates the rams in the up mode correctly and will sometimes engage in down mode.

2) Hydraulic fluid flushed and changed at beginning of last season and still looks OK (1 year ago). No leaks from trim cylinders, all hydraulic fluid hoses and fittings appear good.

3) Trim switch, harness connector and wiring leading up to down solenoid all must be good because the down solenoid ALWAYS clicks.

I've read through the service manual #6 and in my case it seems to be a suspect down solenoid or the connections on the down solenoid. Make sense?

Thanks,
Z

 

[Don S]

Re: 1990 Mercruiser Alpha 1 - Power trim goes up, down only works sometimes

Follow section 1C in the manual. It will lead you to the problem.
Yes it's probably a solenoid, but that is why there are tests to find out for sure before you start throwing parts at it.

 

[Dinows]

Re: 1990 Mercruiser Alpha 1 - Power trim goes up, down only works sometimes

Very Very common problem, it is the soloniod. You should have 2, one up one down. The down one has the green wire. Sierra part # 18-5817 about 17 bucks at any auto parts store. Hope this helps

 

[z0lt3c]

Re: 1990 Mercruiser Alpha 1 - Power trim goes up, down only works sometimes

Thanks for the response guys. Glad I am on the right track w/ the solenoid.

My biggest problem is the hydraulic unit is so hard to reach. On my Larson, it's tucked all the way in the rear corner of the bildge and is obstructed by the molded boat frame. It seems the solenoids are almost facing the stern, making it difficult for me to get in there to replace or test them.

I'm thinking for $20 I will just have the solenoid on hand... Should I just replace both while I am in there ??

 

[Dinows]

Re: 1990 Mercruiser Alpha 1 - Power trim goes up, down only works sometimes

I have 4 on my boat and only replaced one, but I am cheap. yes replace them both. Very easy job. dont forget you can always run a jumper wire from the green wire on the big lug of the solonoid to the red wire to give you a temporary fix. You can actually hold the wire with one hand while the drive goes down. Hope this helps

 

[z0lt3c]

Re: 1990 Mercruiser Alpha 1 - Power trim goes up, down only works sometimes

I decided to take the easy route here and I doused the two solenoids with spray contact cleaner and after letting it dry out overnight, the trim down operates 100% reliably now.

Next I have to figure out why I am stalling when going from idle to F or R.

 

[surftodd]

similar problem--could you guys help me out?

similar problem--could you guys help me out?

1988 alpha one drive system

new--old boat....so I am trying to figure things out still.

old trim pump worked for the first three cruises then would blow fuse when I trimmed up the od

I replaced the fuse and it blew again when I finished the next day of boating and trimmed the od all the way up.

replaced the fuse and that didn't fix it the 3rd time. There was also a milky substance in the trim reservior....water ? Air?? looked like a strawberry shake


went and threw in a whole new trim unit.$$$$$$$

Guy said to install it, add oil, and play with trim. Then once the strawberry shake material was mixed again in the reservoir from the pistons, I drained the reservoir again and replaced with new oil.

while doing this, the fuse blew while the od was going up. I replaced it and then tried and just got a click, then nothing....(from the brand new trim pump!) uGGGGGGG


I have a new switch ordered. the old one in the boat never worked in just "up." I always had to use the trailer and up buttons together. Could that blow the up seleniods?

could the "strawberry shake" blow the solenoids?

The "down" works fine


and.....the is NO sign of a fluid leak from what I can see.....I am lost on this one...help!

Did I just kill a brand new trim assembly?

 

[Bondo]

Re: 1990 Mercruiser Alpha 1 - Power trim goes up, down only works sometimes

I decided to take the easy route here and I doused the two solenoids with spray contact cleaner and after letting it dry out overnight, the trim down operates 100% reliably now.

Next I have to figure out why I am stalling when going from idle to F or R.

Ayuh,... I believe you've probably just prolonged your agony by the Doucin'...
You've got Corroded terminals,... It's the Corrosion Within that's the Problem...
Ya need to take 'em apart, sand, clean, reinstall,+ Grease 'em,...
That'll Stop the Corrosion...

What you've done is etch the metals, they'll Corrode even quicker now...

My Guess is your stalling issue is a Bad lower shift cable, or it just needs a Good tune up, 'n service...

surftodd,... You've gotta start a thread of Your own, about Your boat,+ it's troubles...
It's not nice to Hy-jack zolt's...

 

[BIGALF]

Re: 1990 Mercruiser Alpha 1 - Power trim goes up, down only works sometimes

I don't know if your having the same problem I just had. The trailer button works fine. The drive goes up but it will not go down. The pump is working but no up or down action is taking place. I stoped by a mercruiser service guy today and he thinks it is the fact that the seals on the hydraulic cylinders are frozen. He said it happens when you don't lube the shafts of the hydraulic cylinders. He said oil the shafts and remove the lines then push the outdrive in the down position then hook it back up and try. If it works that means the seals dryed out and stuck to the shaft. This looks like a simple test before you change anything else. I'll let you know next week if it works.

 

[BIGALF]

Re: 1990 Mercruiser Alpha 1 - Power trim goes up, down only works sometimes

Just to keep you up to dat. I took my boat to a different service guy and he check the system and all works except the pistons are stuck and will have to be replaced. Of course this is the most expensive fix that I have to do.
" A boat is a hole in the water that you just keep pouring money into"