74 Mercruiser 165 I/O stern drive will not lower

[tonync]

Hey folks,
1st time boat owner here and I am feeling like I just made a huge mistake.. Not really, but starting to see my ignorance coming through. I just got a 74 Glastron 18' Swinger with a Mercruiser 165. i assume it is Alpha I from what I gather here. I have seen this boat run but since I brought it home, I have spent time cleaning it up. When I brought it home, I moved the trim up to store. Now I read on here you are supposed to store with it down but lesson learned. I got "water muffs" to start it today before taking it the water the first time and I tried to lower the trim and it will not lower. I hear the motor but no movement. I need to add that the trailer switch never has done anything since I brought the boat home. Anything suggestions on what to check?

 

[chiefalen]

Re: 74 Mercruiser 165 I/O stern drive will not lower

thats a pre-alpha.u ever get a manual?i bet not cause u didn't know what drive.first thing anyone should do is get a manual.boats ain't like cars if u want to work on them yourself u have to know the internals.the manual will have a diagrams for the electrical wiring.don might have them and post it here for u.

 

[ziggy]

Re: 74 Mercruiser 165 I/O stern drive will not lower

yep, a service manual would be a good place to start for sure... there's even a trobleshootin guide in it for trim systems...

http://forums.iboats.com/showthread.php?t=251571

looks like ya need #2... confirm ya got the right one by s/n....
give it time to download too. it's a big file.... 1.08 gb.....

 

[Haut Medoc]

Re: 74 Mercruiser 165 I/O stern drive will not lower

Try standing on it while an assistant hits the 'down' button......
Sometimes they get sticky from oxidization/the shafts get dry......
The system has way more pressure 'up' than 'down'......
Check the pump fluid level, (large screw, SE corner), 5w-20 or tranny fluid, check what is in there with a cotton swab & don't mix oil & tranny fluid.....
It should be full to the bottom thread......
Cycle it through a few times to make sure it's functioning properly.....
If that doesn't do it, you will need to troubleshoot with the book.....
Do download the link Ziggy gave ya, well worth it........​

 

[rocket1968]

Re: 74 Mercruiser 165 I/O stern drive will not lower

Dont forget to check your lines. If you have any oil in the bilge, check for connections and broken braided lines. I have the same engine and year and the lines if original are bad....

You should also hear a change in pitch of the motor after the hydrolic fluid starts hitting a resistance. The pitch of the motor should change and then when it bottoms, you will hear the RPM's drop since it has hit the max drop. (make sure you have clearance when doning this on a trailer, no fun putting the drive into the ground).

 

[Haut Medoc]

Re: 74 Mercruiser 165 I/O stern drive will not lower

Dont forget to check your lines. If you have any oil in the bilge, check for connections and broken braided lines. I have the same engine and year and the lines if original are bad....

You should also hear a change in pitch of the motor after the hydrolic fluid starts hitting a resistance. The pitch of the motor should change and then when it bottoms, you will hear the RPM's drop since it has hit the max drop. (make sure you have clearance when doning this on a trailer, no fun putting the drive into the ground).

Good advice, but bad lines wont prevent it from going down....

 

[MelLandry]

Re: 74 Mercruiser 165 I/O stern drive will not lower

Good advice, but bad lines wont prevent it from going down....

If bad lines drained all the fluid it will. I had this issue last week. Topped off the fluid to get the trim down until I could find the leak.

I have a pre-alpha as well.

 

[Haut Medoc]

Re: 74 Mercruiser 165 I/O stern drive will not lower

I would think if you are leaking fluid, it would go down on it's own....

 

[rocket1968]

Re: 74 Mercruiser 165 I/O stern drive will not lower

Not on mine, it still needed the motor to roll with fluid to move the oil from one line to the other. it is a closed system and moves the fluid from one to the other. Mine would go up, but not back down.

Plus, if you start getting a gurgling noise then you know you have air in the lines and a leak (most likely) When I replaced the line I bled it like a brake line.

 

[MelLandry]

Re: 74 Mercruiser 165 I/O stern drive will not lower

Not on mine, it still needed the motor to roll with fluid to move the oil from one line to the other. it is a closed system and moves the fluid from one to the other. Mine would go up, but not back down.

Plus, if you start getting a gurgling noise then you know you have air in the lines and a leak (most likely) When I replaced the line I bled it like a brake line.

Can you post the process by which you bled it? Might help someone out (me).

 

[Haut Medoc]

Re: 74 Mercruiser 165 I/O stern drive will not lower

The system is self bleeding, but you can expidite that by loosening the nuts on the trim rams & let it drift towards the down position.....
Air can get trapped at the reverse lock out valve....Same deal.....​

 

[ziggy]

Re: 74 Mercruiser 165 I/O stern drive will not lower

The system is self bleeding,

yep, that's what the service manual says for normal conditions....however, there is a bleeding proceedure for total loss or partial loss of trim fluid... it's on pp. 7A-7 of service manual #2... there's an up procedure and down procedure......

 

[tonync]

Re: 74 Mercruiser 165 I/O stern drive will not lower

Thanks everyone for your advice. I downloaded the manual and believe that will be a great help. I plan to try to work on the problem tomorrow and will keep you posted on progress and what I found the problem to be.

 

[tysonnathan]

Re: 74 Mercruiser 165 I/O stern drive will not lower

In my experience, a busted line will prevent the drive from trimming down. I was on the lake one day and trimmed up to bring up the bow. When I tried to trim it back down, it wouldnt go. Even with the force of the engine pressing it down at cruising speed it would not trim down. Found the fluid in the bildge... added a little to the resevoir to get it down. Found the busted line when I got back to the house.

If your fluid is low, do not top it off with the cylinders extended (trimmed up). The outrive must be all the way down when you fill the resevoir. Otherwise, when you trim it down, all the fluid in the cylinders will have nowhere to go. Just add enough fluid to get it to start working, then let it all the way down to top it off..... If that is the problem.

 

[tonync]

Re: 74 Mercruiser 165 I/O stern drive will not lower

Ok... I got it working yesterday. It was just stuck and I had to jump on it a couple times while my roommate togled the up and down switch. I was worried about all the weight on the stern drive but it worked! What a relief! I appreciate all the advice and I am sure since this is just the 1st porblem I have ran into thast I will be posting a lot more questions. you guys are great!