Velvet drives : Allignment and testing out of water?

[tmh]

Hi. I bought a used 1988 cruiser with twin Mercruiser 454's and inline velvet drives/transmissions (72C, 1.91 gear ratio). I was told the current drives are not functioning properly by the current owner prior to purchase, the engines run fine. however, the previous owner never put it in the water and has no idea what is or isn't wrong with the velvet drives.

So... I am getting it working with the help of a mechanic friend of mine (not a full-time marine mechanic but a very good auto/engine guy). He's done lots of work on I/O's butnot as familiar with inboards. So I have some questions.

It COULD be that the drives are indexed for the wrong rotation of engine and only need to be switched. However, it could also be they need replacing or rebuilding. I researched as much as i could find and know these drives can be used on either a RH or LH motor, but need to be set up for whichever they are on. Either way they reverse the rotation to the prop. THAT much I get.

My question is, how do I know if they are working without testing while the boat is on blocks? Can I engage them without cooling water ? I know I need the water to the engine and I know how to dothat now, but the drive and bearings also? Need two hoses?

So, assume I can test them on land then I get them working. I read they should get final alignment after the boat has been in the water for a day or two. This boat sat on blocks for two years so I think I should follow that advice. How do i align them to test then? I don't want to launch it THEN find out the drives still aren't working.

Any help or links to instructions would be appreciated.

Thx.

 

[ken_23434]

Re: Velvet drives : Allignment and testing out of water?

Section 8 of Mercruiser Service Manual #3 talks about Velvet Drive Transmissions. I haven't read through it, but I would guess it would cover your questions.

Here is a link to it. This will take you to the "Adults Only" sticky at the top of the forum.

 

[ken_23434]

Re: Velvet drives : Allignment and testing out of water?

I took a look at the manual better. Section 2-I talks about alignment of the engine and transmission. Section 8 just covers the drive itself.

As for your question about providing cooling to the drive, section 7 has drawings showing various setups. It looks like the raw water passes through the trans cooler before going to the engine. So, depending on where you are supplying the water to run the boat on land, you might be still feeding the trans cooler. You would just need to trace out your exact system to verify. The drawings in section 7 should help you know what to expect or where to look.

I hope this helps you out.

 

[Don S]

Re: Velvet drives : Allignment and testing out of water?

Service manual #9 is the one for your engine and tranny. Plus it's a heck of a lot smaller download.

 

[tmh]

Re: Velvet drives : Allignment and testing out of water?

Thanks guys. I downloaded it and am trying to digest the info. I'll also show it to the mechanic helping me do the work. It is a bit involved but not too bad from the looks of it.

I didn't read all yet - anyone know if alignment needs to be done in the water of boat has sat out a while?

Thx.

 

[ken_23434]

Re: Velvet drives : Allignment and testing out of water?

In the section labeled "ALIGNMENT" the first statement is

IMPORTANT: Engine alignment must be chedked with boat in water, fuel tanks filled and with a normal load onboard.

So, I would perform the alignment with the boat in the water.

 

[Don S]

Re: Velvet drives : Allignment and testing out of water?

Do the alignment on land to start with. Get it within .003" THEN put it in the water. Let it set and settle for 24 hours, then recheck the alignment. Most small boats do not change much and wll be fine. Large 30+ foot boats change quite a bit when put in the water.
One good thing about doing the job on land first, you then know what tools you will need to readjust when in the water if needed.

 

[seven up]

Re: Velvet drives : Allignment and testing out of water?

All the best with your new purchase.

Your transmissions should not be engaged while connected to the propeller shafts and on blocks because of the cutlass bearings in the struts on the bottom of the hull. They need lots of water to keep from burning up.

The tranny fluid needs to be clean and also clear of contamination from a faulty transmission cooler.

All the manuals for your velvet drives should still be available with an internet search as well as parts and repair facilities.

Nigel Caulder(sp) has written a book specifically on inboard propulsion you might want to check out. Great information on shaft log and packing, too.

 

[picklenjim]

Re: Velvet drives : Allignment and testing out of water?

If you put motor oil on your cutlass bearings you should be able to test it out of water without hurting it.

 

[Don S]

Re: Velvet drives : Allignment and testing out of water?

DO NOT USE MOTOR OIL!!!!!

It could damage the cutlass bearing. Just put another hose on the cutlass bearing. with a small stream of water for luberication. You won't be running it long or fast just to check the shifting and operation.

 

[tmh]

Re: Velvet drives : Allignment and testing out of water?

Thanks as always guys. great help!

 

[seven up]

Re: Velvet drives : Allignment and testing out of water?

Lots of great advice on how to destroy your cutlass bearings.