1980 470 pre-alpha wont lower

[xsnrg]

Hello all.My problem is my outer unit will not lower all the way,full in.It will raise ok but i have to stand on it to get the outer unit to lower all the way.I have a 1980 470 mercruiser with a pre-alfa outer unit.The boat is a 1980 silverline.This is my first boat so i have alot to learning to do,so if someone could just point me in the right dirrection.Thanks......X

 

[Trent]

Re: 1980 470 pre-alpha wont lower

We first need to know if its the outdrive.Lower the trailor tongue as far as possible. Remove the rear trim cylinders attach points and see if the drive goes up and down easy by hand and come back here.

 

[xsnrg]

Re: 1980 470 pre-alpha wont lower

Thanks Trent,ill check that out on monday and post a responce.Till then,have a good one.

 

[xsnrg]

Re: 1980 470 pre-alpha wont lower

Ok,I removed the rear trim cylinders.The drive assembly moves freely.Tried to extend the cylinders while they were disconnected from the drive,noticed that the cylinder on the starboard side extended slower than the one on the port side.....X

 

[xsnrg]

Re: 1980 470 pre-alpha wont lower

Bump^^

 

[oldray]

Re: 1980 470 pre-alpha wont lower

Had the same problem with my drive (74' searay). After tearing apart my entire system, bleeding everything I don't remember how many times. I found that the reverse lockout valve that is part of the shift plate mechanism had a spring return problem. The spring is internal on my setup and was caught on itself not allowing the plunger to return to the correct position. You have to take it apart to check, but it wasn't too much trouble on my setup.

 

[xsnrg]

Re: 1980 470 pre-alpha wont lower

Ok so I took the valve apart and all seemed well.Still wont retract.The part number for the valve is 76812,anyone have any expolored veiws of this part?My system apears to be the Prestolite trim pump.

 

[xsnrg]

Re: 1980 470 pre-alpha wont lower

Bump^^ again for the night crew

 

[Trent]

Re: 1980 470 pre-alpha wont lower

If it was me Id probably rebuild the trim cylinders. Look at this service bullitin. I think it might help??? Let us know. And good luck.<br /> web page

 

[xsnrg]

Re: 1980 470 pre-alpha wont lower

Thanks Trent,ill let you know how I make out.

 

[xsnrg]

Re: 1980 470 pre-alpha wont lower

 

[xsnrg]

Re: 1980 470 pre-alpha wont lower

I rebuilt the trim cylinders and all is well.All they needed were new seals as the seals in it were hard and seal on the inner tube guide crumbled to touch.Thank for all the help.