whats the difference between these two couplers
 

one is from the 454 i took out the other is from the 502 im putting in
not sure what changes I need to make to install the 502 now

thanks again in advance[ATTACH=CONFIG]519977[/ATTACH][ATTACH=CONFIG]519978[/ATTACH]

Looks like the 454 is the long snout and the 502 has the std coupler. Same spline nothing to change.

The coupler on the right is an aluminum coupler .The coupler on the left is Mercury's heavy duty coupler made for heavier boats that idle a lot or troll alot.the quality of the hd coupler far exceeds the aluminum coupler.

There are 2 versions of the short coupler, aluminum and steel. I might be wrong, but I don't think the aluminum one is available any longer. The short one is necessary for driveshaft applications.

the one on the left is a gen II alpha coupler ,,,,
this is the heavy duty bravo coupler http://www.bing.com/images/search?q=...lectedIndex=10

the one on the right is just the standard duty big block coupler..

One is a penis the other a vagina. Your mom not teach you about the birds and the bees??

no she died when i was young a s shole...thanx your comment just brought the worse day of my life...

besides, they are both vaginas. one is just fatter than the other...

So I guess ill need ti swap them to install the 502 in my boat with a bravo?

Fixx if I`m referring to you I`ll quote you otherwise I`m replying to the OP. Internet 101 so calm down there buddy

Sounds like the heavy duty one is what you should run with a high performance (i.e. 500+ HP) engine. Too bad it is about twice as much as a standard Bravo coupler. I personally don't know anyone running the heavy duty one - two friends of mine were both running supercharged engines on the standard coupler and have not heard of any failures. I guess if you are running a big heavy boat with a lot of power it might be worth the upgrade. Main thing is keep those splines greased!

If it's just a stock 502 in a 24' to 28' boat I would think that the standard Bravo coupler would do fine as long as you keep on schedule with your maintenance and don't do crazy stuff like a lot of holeshots and wake jumping.

It will be fine I've run 550+ hp in a 40' 10k boat

Regardless of what coupler you select -- Make sure you check engine alignment - I would guess it doesn't matter which one you select - if your engine is out of alignment it will chew it up in no time-- I've got the bills to prove it!

3pointstar

I have almost no experience but are you sure thats an alpha coupler? I ask because the guy I bought the motor from had a bravo xr drive?

Yes its barely 400 hp in a 5k boat (26 ft)h
can anyone confirm or clarify that the vagina is in fact an alpha coupler as FIXX suggested? I'm pretty sure the previous owner ran a bravo

if it looks like this one which it most likely will http://www.perfprotech.com/mercruise.../product/73521 then its a alpha one which has 3 bolts holding it to the flywheel..make sure the splines on the 502 coupler are not sharp at the edges,you should feel knurming or some machined slits in it when you stich your finger in the hole..if it feels sharp on the edges then it needs to be replaced..

did he say something about sticking a finger in a hole?

better a finger than something else lol
The post actually confused me because the photo of teh vagine coupler in my original post is the actual coupler.
This post says "if it looks like this its an alpha" but the photo in that link is an "outy" similar to the coupler on the 454 which is a bravo coupler for sure.
I just need to confirm if the "inny/vagina" coupler will fit my bravo
I guess I just need to try it when the drive comes back from teh paint shop?
Ill have to really stick it in!

I believe couplers are interchangeable. just how long lighter one lasts with a heavy foot.

alpha and bravo couplers are interchangeable?

The inny is the same coupler that came on my 454 mags. If you take the bellhousing off you will see the inner plate is round and has about 8 bolts connecting it to the flywheel. The couplers with a three bolt pattern attaching them to the flywheel are what you do not want. I would take a picture with the housing off and ask again.

The one on the right is a HP coupler for a Bravo drive. It is round and six bolts hold it on the flywheel. I got mine from CP.

thanks
Ill do that tonight

...........

thanx buddy,,ill have to remember that next time you call me when you have issues with your sub tub!
if you read the discription is reads 14'' alpha coupler..i have never seen a bravo coupler that bolts to the flywheel,only that style that has studs and the flywheel and coupler mounts to them from what i have seen is either a king cobra drive and a mercruiser mr and r drive..

Stimleck I have run both couplers ( one on left with the triangle mounting plate is typically on small displacement motors ) and the HD one on the right ( round mounting plate with blunt end found on large displacement apps ) behind my BBC with no issues. I changed mine when I swapped from an Alpha to a Bravo 1 for piece of mind but don't think I would have had any problem using either.

So in case anyone is around for advice the 454 coupler only had 3 bolts and came from the factory with a bravo the coupler opening wont fit the alignment tool its too tight what should I use?

the alignment shaft should fit in either one alpha and bravo splines are the same size .. i have to agree the pic on left looks to be a alpha coupler .one on the right is def bravo

seems like you have the wrong alignment tool

Stimleck = where are you located??

hi folks well it turns out that the tool fits fine I just needed to push a bit doh! the stock 454 coupler only had 3 bolts the coupler on the 502 had 8 I think
I stuck with that one, I did notice that the 454 had a plate behind the flywheel, is that mandatory?

located in toronto

plate behind flywheel is probly balance plate to adapt 350 or other neutral balance flywheel to ext balance 454. not NEAR as good as correct flywheel. also, they could be wrong about needing it or getting correct one. ck flywheel part number and look for balance weight cast into outside of flywheel.

Full circle coupler on the 502 and other bravos ,is held on with 6 bolts...