Drive won't go down, unnecessary reverse lock?

I have a boat that's a mutt, bits and pieces from all over and I can't tell which model of trim pump I have the numbers are worn off. It has a squarish base to it and it's metal, not plastic. If I rememer right, the boat that I pulled this out of had the linear style sender and the trim plate did in fact have a reverse lock that this ran through, but this looks like a prestolite to me and if I am right the prestollites have built in check valves no? Regardless, I'm ready to cry and kick the dog over it (not really of course relax everyone, I'd slap one of the kids if I really need to take it out on somebody

If someone has a plan for me I'd love to here it...I really want to be able to take this boat out just once before it gets too damn cold. The picture I added isn't the actual pump, the boats not here right at the moment, but it looks just like this one....thanks.View attachment 118961

Re: Drive won't go down, unnecessary reverse lock?

That is indeed a Prestolite pump.... However... they come in 2 flavours (of course!), one with internal 'reverse lock valve' and the other without. If you removed yours from an engine with a linear style trim sender, the pump does NOT have the internal reverse lock valve.... Either fit a valve (not easy), or find a pump that has the valves....

Chris.........

Re: Drive won't go down, unnecessary reverse lock?

achris said:

Either fit a valve (not easy), or find a pump that has the valves....

Click to expand...

Do you mean fit a check valve? What happens if I bypass the reverse lock and it doesnt' have a check valve? I don't plan on doing it, I've learned enough to know that it's best to just do things right the first time, but maybe if I understand it better I can figure out what's wrong with the components it has.

Thanks

Re: Drive won't go down, unnecessary reverse lock?

Leedanger said:

Do you mean fit a check valve?

Click to expand...

Sorry, I should have said 'fit an external valve'.

Leedanger said:

What happens if I bypass the reverse lock and it doesnt' have a check valve?

Click to expand...

You won't have a reverse lock in the trim system so when you put the drive in reverse, it will 'kick up'.

Leedanger said:

I don't plan on doing it, I've learned enough to know that it's best to just do things right the first time, but maybe if I understand it better I can figure out what's wrong with the components it has.

Click to expand...

You have manual #6... Have a read of page 5C-2 "Description", and in Manual #4, page 5-4 has a picture and description of the external reverse lock valve.

Cheers,

Chris.......

Re: Drive won't go down, unnecessary reverse lock?

Many thanks as always!

Re: Drive won't go down, unnecessary reverse lock?

Is your pump in the 75 boat you have in your profile? If so, and the trim system is for that year also, manual #2 may be the one you want to cover your trim pump.
http://www.4shared.com/document/3AHpVLYw/Service_Manual_02.html

Re: Drive won't go down, unnecessary reverse lock?

What does.. the drive wont go down got to do with the reverse lock valve?

If the drive is stuck in the up position and the reverse lock valve is open (marks line up) or even not installed and the pump runs.. mostly the check valve (to keep the leg up) in the valve body is stuck.
When it sits for some time with water/ moisture in the system, the check valve seizes.
The drive moves op, the valve shuts and the pump its oil pressure to move down (low pressure) is now not sufficient to operate the plunger that opens the check valve to to lower the drive again.
Run the pump trim down and add some weight to the leg and see it if it brakes loose.


Good luck!