Mercruiser keyholes....

[boatnut74]

I think this is the right place to post this. I'm restoring a 72 starcraft chieftain that has the 165hp inline 6 and mc1 drive. I picked up a '91 4.3 alpha one gen 2 I want to swap in. I think I read somewhere the keyholes are different? How much difference is there between the two? I really don't want to put a patch on the outside of the transom but am thinking I might have to.

 

[Don S]

Re: Mercruiser keyholes....

The cutout is the same. You will need to drill 2 additional holes for the Gen II.
Here is an installation manual that may help you out. The transom thickness and flatness are critical in your rebuild.
http://www.boatfix.com/merc/Install/gas/86017211.pdf

 

[boatnut74]

Re: Mercruiser keyholes....

Thanks Don, looks like I just need to drill 2 new holes at the top.
Would you reccomend getting the driling fixture? It's a little pricey but seems like it would save alot of headache.

 

[Bondo]

Re: Mercruiser keyholes....

Ayuh,... Being a 72, the top 2 holes there now, may need redrilling....

I use a cordless drill, 'n speedy-square to eyeball the holes...

 

[boatnut74]

Re: Mercruiser keyholes....

How far off will the top two holes be? My eye-ballin usually aint that great. Bond-o, do you by chance have any pictures of the engine mounts you fabbed up in your Islander? That will be the next challenge.

 

[Pete104]

Re: Mercruiser keyholes....

You can buy a template from a dealer. Don't know the P/N off hand, but they're like 5bucks. Lay it out & drill. The more square, the better!

 

[boatnut74]

Re: Mercruiser keyholes....

I thought about the template for a layout and might still go that route. The fixture is about 350 bucks but would be nice.

 

[Bondo]

Re: Mercruiser keyholes....

The fixture is about 350 bucks but would be nice.

Ayuh,.... Yer missin' the Beauty of workin' in fiberglass,...

If ya miss yer mark, pack it fulla fillings, 'n it's ready to try again, in No time...

I've done a 1/2doz. by hand, 'n participated in a couple done with the jig,...
It's Nice, but not $350. Nice, unless yer doin' it regularly...

My bag of jigs consists of an ole aluminum transom skin, that once had a very old mod.1, then an R or MR drive, then an Alpha, Gen.II on it...
There IS a difference in the upper holes of the Very old Mod. 1s, by halfa hole...

I've also got an ole stripped to the bone, except the studs, Bravo outer transom housing, 'n it's inner plate, for "Test" fittin' things...

Cost me nothin' but beggin', 'n dumpster divin'....

 

[boatnut74]

Re: Mercruiser keyholes....

Maybe I could find a shop that would let me borrow or rent one. Or like you said I can always refill the holes if I miss. I plan on drilling them oversize to begin with, then filling them back in and redrilling, just to make sure no water can get to my new wood.