Bravo alignment tool
 

I have a year 2000 454 mag mpi with bravo drive. Im trying to check the alignment from from gimbal to coupler. I got my hands on a factory mercruiser alignment tool part #805475 that is supposed to work on all bravo drives. well just as my luck would have it it will not fit in the coupler, fits the gimbal bearing fine but not the coupler. I put a micrometer on the coupler end of the tool it mics out at 1.010 I believe my coupler will only allow a tool of 0.985 to fit. I have talked with my local mercury mechanic in town and he thinks im out to lunch. I am having a tool made by a good friend that will work. Does any body have a clue on what i am talking about and can tell me what the deal is it would be greatly appreciated.

Are you sure your alignments just not off preventing the tool from going in?

Yes i started fishing sockets up in the coupler taking the gimbal bearing out of the equastion and found one that was close. then i got on line and found an old thread on a different sight and he gave the magic # of .985 so i turned a chunk of round stock down and it fits perfect

If you bought it from Ebay theres a chance it could of been mine.
Anyways that tool is on at 1.010 and should fit your coupler.
Your engine is probably out of alingment.
There is not a standard bravo with a different size shaft/coupler needed that I ever have heard of.
Measure your drive shaft off the drive.

You stated that there is a chance it could be yours. If so, did you manufacture it or is it truly a Merc part?

If its mine its not a Merc part.
Merc will still be the same size give or take a few thousandths.

The drive was replaced with a factory reman merc drive in 2005 or 6 . maybe the coupler was done at that point but I do not know. Not sure if an after market part might create this condition or not

Then the motor would have been pulled to change.
Unless there is a company selling remanufactured drives with different couplers which would make no sense at all.
Who would want to pull there motor to put on a remanufactured drive.

If it fits the bearing it will fit the coupler! My bet is it is either out of alignment or when you pulled the drive you let it drop down with the shaft still in the bearing and have knocked the bearing out of whack. Try this shove the tool in and hold it in hard, take the palm of your hand and and whack the end of the tool is side to side several directions to try to align the bearing. If the bearing is slightly cocked you will not get the tip into the coupling, takes awhile to get the feel for doing this stuff. The tip of the tool needs to be coated with grease to be able to get the correct reading of the spline pattern, also just because it goes in does not mean it is lined up.

I Just Measured Mine,it Is Origional Merc Tool,i Have Had It For 12 Years.it Is 1.005 In Dia.if You Base On .985,you Will Not Get Correct Alignment.

I have a hard time believing that anyone anywhere would put a different size coupler on there. I think it is just out of alignment.

I own a tool that Whoya made and it fits mine nicely.

Are the splines in the coupler pointed and sharp?
When the coupler gets worn from misalignment, they can get sharp points, which are deformed splines, actually making the ID measure smaller.

If they are pointed/sharp, time for a new one.

US1 thats the first thing that has made sense to me so far I will look closer at the splines to night. I just bought this boat back in october and have been working on the inside and such throughout the winter when I noticed the left side motor mount nut had backed off and the motor had dropped down about an inch. so i raised the motor back up to the upper nut which has a nylock and did not move as far as i can tell. Thats when I pulled the drive. Ginger or Mary Ann? I will take both :drink:

My bet is the couplers are shot then and the root of your problem. They should have flats on them, no points.

The ID of the splines (which you were checking with sockets) is larger than the depth of the input shaft teeth, so with a misalignment the metal is deformed and will fill in this clearance, hence the reason the tool will not go in now.

Yeah, the upper nut never moves. Always screw the bottom nut back up lifting the motor back in place. Usually that will bring the alingment back in.

Good luck