Mercruiser questions

[trucktramp]

I have a 1975 vintage Starcraft with a Mercruiser outdrive that will raise but not go down. What gives?? The guy I bought it from said that it is normal and the prop will help push it down. I didn't believe it then and I still don't believe it. This is my first I/O so my knowledge is limited. I'm itching to get it in the water soon but I want everything working ok.

 

[Bondo]

Re: Mercuruiser questions

Re: Mercuruiser questions

Ayuh,... It's probably corroded, lacking grease,+/or the ram caps are seizing....

Start taking it apart til you find the Tight spot...

 

[JaseBosto]

Re: Mercuruiser questions

Re: Mercuruiser questions

Uh, sounds to me like your power tilt system is worn.... maybe a little more info on exactly whats happening when you push the button...do you hear the pump motor working? If so, then bondo's answer sounds spot on.

 

[zbnutcase]

Re: Mercuruiser questions

Re: Mercuruiser questions

Those pumps don't have a lot of down pressure and usually like Bond-o said corrosion builds up in the cylinder caps causing them to stick. 'nutcase

 

[trucktramp]

Re: Mercruiser questions

I can hear the relays clicking and the pump running both up and down. I goes down a very little way and goes up just fine.

 

[JustJason]

Re: Mercruiser questions

the shuttle valve inside of the pumps also stick over time. With the motor off and the drive up, have a heavy person stand on the drive while trimming down, see if that does it.

 

[trucktramp]

Re: Mercruiser questions

Finally got around to rechecking the outdrive. It does go down with someone pushing on it but it goes down very slow and the pump sounds like it is really working. It goes up at a normal speed and the pump sounds normal. I haven't torn into the cylinders yet but that is next.

 

[jerryjerry05]

Re: Mercruiser questions

Lube the shafts of the trim cylinders.J

 

[lonemust]

Re: Mercruiser questions

I would change the fluid and make sure you have fluid flow though the lines before tearing it apart.

 

[trucktramp]

Re: Mercruiser questions

Ok, so here's the next dumb question. Once I crack the lines to check them or take apart the cylinders, how do I bleed the air out of the system?

 

[zbnutcase]

Re: Mercruiser questions

Go to sticky at top of page and download the service manual, it explains all of that.

 

[mrsaundep]

Re: Mercruiser questions

Trucktramp - I have same problem. Comes up fine, won't go down unless somebody pushes the stern drive down or the boat is making way. With the boat out of the water I lubricated the trim cylinder shafts and worked them up and down until they went down on thier own. However after a few weeks back in the water the problem was back. I can live with out though until the end of the season and I have purchased a new pair of cylinders. You can get an overhaul kit but old cylinders are difficult to open up.