1972 Mercruiser 888 New Transom, Cutout template or measurements

[rocketboy52]

I spent the last hour searching the archives and that is a TON of awesome stuff on here. I'm really excited to finish my boat project. I've recently glassed in a new transom in my 1972 winner viscount and now I need to cut the keyhole and drill the outdrive mounting holes. I have some pieces of the the old transom, and a new inner transom plate that I could use as templates but in one of the old threads I found a link to this product:
MerCruiser Transom Drill Fixture

This would be sweet, but it says in the description that it wouldn't work for my Pre 1976 model. I found The Mecrusier Installation Manual 86017211.pdf in another response, and it talks about a full size template drawing that can be used to location the features, but I haven't been able to find a copy of this anywhere. Anyone know if the above transom fixture will work for my out drive?
Thanks!

 

[achris]

Re: 1972 Mercruiser 888 New Transom, Cutout template or measurements

They are right. That fixture will NOT work for pre-1976. A couple of the holes are in different places and the cut-out itself is slightly narrower in the centre.

The number for the old fixture is 91-38788A3. Hope that helps.

Chris......

 

[Bondo]

Re: 1972 Mercruiser 888 New Transom, Cutout template or measurements

I spent the last hour searching the archives and that is a TON of awesome stuff on here. I'm really excited to finish my boat project. I've recently glassed in a new transom in my 1972 winner viscount and now I need to cut the keyhole and drill the outdrive mounting holes. I have some pieces of the the old transom, and a new inner transom plate that I could use as templates but in one of the old threads I found a link to this product:
MerCruiser Transom Drill Fixture

This would be sweet, but it says in the description that it wouldn't work for my Pre 1976 model. I found The Mecrusier Installation Manual 86017211.pdf in another response, and it talks about a full size template drawing that can be used to location the features, but I haven't been able to find a copy of this anywhere. Anyone know if the above transom fixture will work for my out drive?
Thanks!

Ayuh,.... Did ya do the work from the inside of the hull,..??

Isn't the original cut-out still in the outer glass of the transom,..??
If so, you've Got a template, right there,....

I've done many transoms just by usin' the original cut-out as a guide,...
Just be careful to keep yer cuts, 90? perpendicular to the transom glass,...

I cut atad wide/ deep/ big, 'n then slather the raw wood with resin putty to seal the new wood,...
With that in mind, If ya cut wrong, or to big, just build it back with yer resin putty,...

 

[rocketboy52]

Re: 1972 Mercruiser 888 New Transom, Cutout template or measurements

Achris,
Thanks for the part number, Google and EBay don't find anything to buy immediately, so it looks like I'm on my own.

Bondo,
I was planning on doing just that, trace the template, but I figured I would scour the forums first. My transom actually ended up a tad thicker then the original. I was worried, but it turns out to be 2.125" thick, including the OML and IML glass and gel coat. After finding the Mercruiser installation document that I found in the archives (linked below for future searches), I see that 2.125 is fine and inside the acceptable thickness of 2.0-2.25". SWEET - I'm golden.

http://www.boatfix.com/merc/Install/gas/86017211.pdf

I just know cutting and drilling through that thick of a part can sometimes be tricky. I have drill cup that I'll ust to try and keep the holes straight, but that drill fixture looks like it would make this task sweet. Knowing that you've done it this way gives me some confidence to just go for it. Any other tips or advice? The tiller clearance reliefs would also be cool with the fixture, I figure I'll have to grind to fit using a barrel sander.

Here a couple of Pics of the recent work:
Outside shot of the Transom getting bonded in with my home made transom clamp


Inside shot:


Outside Shot after the Clamps are removed:


Inside Shot after the Clamps are Removed:


Inside the Hull after the inner glassing was curing under the shop lamps:

 

[Bondo]

Re: 1972 Mercruiser 888 New Transom, Cutout template or measurements

Any other tips or advice? The tiller clearance reliefs would also be cool with the fixture, I figure I'll have to grind to fit using a barrel sander.

Ayuh,.... I use a roto-zip tool as a die-grinder, with a really aggressive carbide bit to hog out the edges, 'n tiller slots,...

A speed-square held near yer drill, while drillin' the holes, helps ya keep yer alignments at 90? to the transom,....

'n,... like I said, if ya screw up, fill it with peanut butter, 'n try again,....

 

[haulnazz15]

Re: 1972 Mercruiser 888 New Transom, Cutout template or measurements

Ayuh,.... I use a roto-zip tool as a die-grinder, with a really aggressive carbide bit to hog out the edges, 'n tiller slots,...

Yup, I used the same thing. The Rotozip will chew through it pretty easily.