Broken Drive Shaft?!?!

[Tinkerer]

Daredevil - put your boat into a turn and leave it at that angle at full throttle constantly and lets see how long your coupler lasts.
Were not talking the 1 to 2 % of the time that you are turning - we are talking 100% of the time.

[Tinkerer]

QUOTE

See how you can move the whole assembly around - That is why a double U joint WILL allow side loading and a single will NOT.




how can that be if the double u joint is behind the bearing that is fixed ?????

The center of the coupler is not fixed - it is rubber mounted. It can flex
Explain to me why the rubber part of the coupler goes out. ( I know the answer - do you )

[Tinkerer]

Not to jump in here ,,,,,,but you are saying if my rear mounts sag down ( 1/8 inch ) all i have to do is lower the front and i will still have the coupler in one line with the gimbal bearing ??????? mmhhhhh makes no sense at all !!!!!!!!

Look at you r diagram - now lower the back of the engine a small amount and the front of the engine a larger amount - Your drive shaft line still lines up with the gimbal bearing. ( remember the gimbal bearing will swivel to any angle to match the shaft)

[Geronimo36]

Tinkerer, do you do this for a living or do you tinker?

[blackhawk]

Wow, I can't believe how many of you guys can't put your head around this. I have never came across sagging mounts but this makes perfect sense to me.

Rear mounts sag alignment tool won't go in.
Lower front of motor, slide alignment tool in, gimbal bearing swivels down slightly, tool slides into coupler easily, you think engine is aligned, it's not.

[DAREDEVIL]

Wow, I can't believe how many of you guys can't put your head around this. I have never came across sagging mounts but this makes perfect sense to me.

Rear mounts sag alignment tool won't go in.
Lower front of motor, slide alignment tool in, gimbal bearing swivels down slightly, tool slides into coupler easily, you think engine is aligned, it's not.

I realy don't think the bearing swivels !!! 2nd. if u use the aligment tool properly it should not go in.

here is a picture of an aligment tool ( the one i have ).
The ring on there ,goes in to the gimbalhousing to keep it centered so if u now try this after the aligment is off,,,,it will not work !!!! ( because the ring will not fit the hole in the housing )

Tinker,,,PM me for my adress and send me the check !!!!!!!!!!!!!! SORRY

[MOBILEMERCMAN]

Wow, I can't believe how many of you guys can't put your head around this. I have never came across sagging mounts but this makes perfect sense to me.

Rear mounts sag alignment tool won't go in.
Lower front of motor, slide alignment tool in, gimbal bearing swivels down slightly, tool slides into coupler easily, you think engine is aligned, it's not.

I am glad you get it.

The corrective action for a sagging mount is to replace them as a pair. Not lower the front of the motor. Simple, end of discussion

[MOBILEMERCMAN]

It is my suggestion to anyone changing a coupler to pull the motor with out moving the adjustable mounts. Either pull the mounts or take some measure as not to move then nut. Change the coupler, set motor, grease the tool and slide it in. The grease will leave a mark to see with a flash light. If the tool hits the back edge of the coupler and misses the hole the back of the motor is incorrect. Correct the height issue in the back do not lower the front. If you find you are making major adjustment in the front something is likely wrong in the back.

[Tinkerer]

Daredevil - The bearing DOES swivel...

Mobile - replace both rear mounts - NO S H I T - What I am talking about is that there is more to it than just sliding the tool in and it is good to go.

Blackhawk get's it. I guess the EXPERTS don't yet understand.

[Tinkerer]

Mobile - so you are saying that if the tool goes through the gimbal bearing and doesn't enter the hole in the coupler - then the rear of the motor has dropped.

Not always true.
What happens if when the drive was removed the gimbal bearing get bumped just a little bit.

When I check for alignment I always move the gimbal bearing arround in it's carrier to make sure that it is not locked in place.

[Tinkerer]

Blackhawk - They don't get it - now they think that we are saying to solve the rear mount problem is to lower the front of the motor.

Mobile - if you have been doing this for 30+ years you should be able to figure this out.

Geranimo - It seems that I know more than the EXPERTS.
I am an HVAC company owner - that is how I make a good living.
I used to build racing engines for a hobby. ( liability ins. got too pricey )
I have worked on high performance boats for 31 years now.

[MOBILEMERCMAN]

Yes, the bearing can swivel that is why it is called a gimble bearing. It is tight and should not move during operation. Yes, moving the bearing is part of the alignment process.

If the gimble was so loose it moved when you removed the drive replace it.

[Tinkerer]

Daredevil - Most of the people on here DON'T have the part that goes into the bell housing - or if they do don't use it or know what it is for.
What I made is about the same as the stock part but with much tighter tolerances to show that everything is not right.

[MOBILEMERCMAN]

Geranimo - It seems that I know more than the EXPERTS.
I am an HVAC company owner - that is how I make a good living.
I used to build racing engines for a hobby. ( liability ins. got too pricey )
I have worked on high performance boats for 31 years now.

I am happy for you.

[MOBILEMERCMAN]

Daredevil - Most of the people on here DON'T have the part that goes into the bell housing - or if they do don't use it or know what it is for.
What I made is about the same as the stock part but with much tighter tolerances to show that everything is not right.

The part that goes it to the bellhousing is for Trannie based applications. In those the rear bearing is in the trannie not on the transom. It aligns the trannie to the drive because it all floats in the transom.

You can go ahead and pat yourself on the your back about how much you know. I have lost track of your point in all this posturing.

[Tinkerer]

All that I am doing is TRYING to show that there is more to checking alignment than what is done by the service and repair shops.

And I am getting flamed for it.

Maybe I shouldn't try to help any more....

Most appreciate the help I GIVE. I don't make any $ from this FREE help.

If you don't want it you don't have to take it.

ALL that I work on are HIGH PERFORMANCE boats.

[MacGyver]

All that I am doing is TRYING to show that there is more to checking alignment than what is done by the service and repair shops.

And I am getting flamed for it.

Maybe I shouldn't try to help any more....

Or try dropping the attitude and stop YELLING.

[Tinkerer]

Mobile - maybe you need to reread the thread.

The whole jist of my coments is that there is more to alignment than what is being done at the so called repair shops. END OF STORY.

That same part CAN give you an indication that the rear mounts are sagged.

TAKE IT OR LEAVE IT - IT IS UP TO YOU....

I still don't have anyone willing to put their $ where their mouth is.

PROVE ME WRONG...................................

[Tinkerer]

Mac - I am not the one with the attitude.

I am not the one name calling.

I am just trying to help.

some people just don't want to learn that there is more to something than what they have been doing for 30+ years.

[Ratickle]

It isn't lack of grease that blows couplers its lack of alignment.

Get an alignment tool - your engine is WAY off.

Here is your first comment. If you want to be a part of the team around here to help solve issues for those of us "Backyard" mechs who try to learn themselves, your first post in the thread should have read something like,

Bad/sagging motor mounts in the rear can cause alignment issues which are difficult to check with the stock Merc tool.

If you work on these as long as you have, you know that is not the most common issue for blowing couplers. These guys still do this for a living, and have for years. And some work on the race boats all over the country, they are not stupid and have saved members thousands of dollars by donating their time and expertise to the site.

Geranimo - It seems that I know more than the EXPERTS.

Wanna bet your thousand bucks on that one????? I'll have my certified Merc mech write the test and send it out.....

ALL that I work on are HIGH PERFORMANCE boats.

You should reword that to, when I'm working on boats, and not working on my business.

I am not the one name calling.

I've really seen no name calling, but as I said about post 2 above, stating you know more than the experts is gonna start issues.




In the meantime, think about it and see if you agree. Everyone with expertise to help is welcome, but we all try to work together to a solution by asking, "what if". If you are saying a sagging rear mount, aligned by lowering the front mounts, is the only/#1 cause of coupler failure, I'd bet you're wrong.....