Trim goes down but not up

[brandonizr]

Just got my hands on a boat, 73 Silverline with a straight 6, 250 cid, 4.1L, 165 hp. Trim worked fine 2 days ago but yesterday I put it down but won't go back up, not even any noises (I'm thinking solenoid)

When I look at the pump assembly, looks like it only has 1 solenoid which is why I'm confused. Shouldn't it have 2? Then I looked at a diagram and saw something about a terminal block on the green side, not sure what that is. I'm pretty sure I have a prestolite pump. I threw a multimeter on the solenoid and had my brother hit the down switch and got a surge of power through it but then let off the switch cuz getting close to the ground. Did that to test where the power was going to on the down switch.

Tried searching but couldn't find any info on an older boat like mine.

Any input would be appreciated, Thank you.

 

[Fishermark]

Re: Trim goes down but not up

The old ones only have one solenoid. I know the Mercruiser manual links were taken down... but someone else has some links I believe. Perhaps they will post soon.

 

[Fishermark]

Re: Trim goes down but not up

I have a pdf file with the wiring diagram... but don't have it online. Here's a couple of views of the trim sections:

 

[Don S]

Re: Trim goes down but not up

Here is a link to service manual #1, it covers both your engine and drive.
http://www.4shared.com/document/ozc1_97A/Service_Manual_01.html

 

[David Foe]

Re: Trim goes down but not up

I had the same problem with my similarly old IL6 starcraft 1975 but, unlike me, I'm sure that you checked that the shift was really in neutral or forward when you tried to raise the drive ... right? I ask because I was a nit wit and didn't realize that that there is a interlock switch that opens when the shift is in reverse that prevents the drive from going up (but it will go down).

David

 

[cr2k]

Re: Trim goes down but not up

Down was run straight in the older units due to lower amp draw for down. My be your relay.

BTW you should put the system you are working on so we don't have to guess it is a MC.

 

[dn010]

Re: Trim goes down but not up

If it is a merc unit it will only have one solenoid. You didn't say if you were trying to trim it up or get it all the way up for trailer. If it doesn't work to just trim then it is bad limit sensor or sensor wires. If you're hitting the trim button and trailer or tilt button and it doesn't work check for corroded wires and bad connections. On an older boat it is important to go through all electrical connections and make sure they're clean.

 

[havasuboatman]

Re: Trim goes down but not up

Before you tear into the pump, unplug the wiring harness at the pump. Then using a jumper that is stuck into the plug at the red/hot wire jump it to the blue wire of the plug. You could use a paper clip, but be quick as it's gonna get hot if the pump kicks in.
If that happens, the pump and it's wiring isn't the problem. Trace the wires back to the helm looking for any breaks. If your trim switch is in the controls handle, you may find the wire has chafed thru and broken. This is not uncommon.
The blue wire or blue with white stripe is the one that lifts the drive when power is applied to it. If your boat has a limit switch, that wire may be purple or purple w/white stripe.

 

[brandonizr]

Re: Trim goes down but not up

Hey Guys,
Thank you very much for your input and advice! As soon as the rain lets up and the Holiday craziness is over, back to working her.

 

[brandonizr]

Re: Trim goes down but not up

Ok, finally dug into this. I changed out the solenoid to no avail but I did notice there are 2 wires that split out of the wiring harness before the motor/solenoid. They look to be purple and green but the diagrams say blue. Not sure if the wire faded green or? They go way back underneath towards the outdrive but not sure where to. Possibly the trim limit switch? These wires are very corroded. Can I jump these 2 wires to simulate a closed connection to test it out? Or bad idea? Sorry for my ignorance, I'm clueless. Thanks.

 

[Bondo]

Re: Trim goes down but not up

Possibly the trim limit switch? These wires are very corroded. Can I jump these 2 wires to simulate a closed connection to test it out?

Ayuh,... If you follow 'em, 'n they Do go out to the drive,...

Yes, By-pass 'em...

 

[brandonizr]

Re: Trim goes down but not up

Can I bypass the switch permanently? Or not a good idea?

 

[Bondo]

Re: Trim goes down but not up

Can I bypass the switch permanently? Or not a good idea?

Oh, I donno,...

Mine's been that way the last 12 years with this barge...

 

[johnzonh]

Re: Trim goes down but not up

I had the same issue last year on our 888 /302 ..switch and wires weren't the problem..but I figured out how to bypass the solenoid. Im not a big fan of using direct connections like that but in order to get the drive up thats what I had to do. I just made my own switch circuit as a temporary fix until I get the new solenoid. for a poor boy like me who only had 5 bucks to make a new circuit...beat paying 30 for the solenoid at the time. good luck with it.