New rebuilted engine hard to align

[frenchman Bob]

Mercruiser 5é7L Bravo II 1997, in a 26 ft half cabin. Recently I had to replace the engine for a rebuilt one I bought in Ocala FL. Same casting number I had before. My mechanic and I installed it in my boat. After intallation, we found out the engine wasn't straight with the boat. It had a small angle to the right, and the alignment bar was very very hard to push in and very very hard to pull out. the front engine mounting adjustment looked good. We toke the engine out to make sure the flywheel housing was properly bolted to the bloc, and it was. We also checked its condition and noyhing looked wrong to us. The transom plate has never been removed and it's in very good condition.
Anyone have an idea of what the problem is?

 

[Bt Doctur]

like I said , remove the lags/bolts on the front, slightly loosen the 2 rear bolts, move engine into correct alignment , mark and redrill new pilot holes for the lags/bolts

 

[CamaroMan]

sometimes the bushings sink in the rear - my best method is to remove ALL mount bolts - see where the motor is lined up, and shim as needed. Last 2 were a real pain and I did this and they are now perfect - alignment tool rotates with 2 fingers only.. Too many variables with rubber bushings, stringers sinking etc etc - i wouldnt redrill anything until i tried my method - its always worked.

You need a gantry or some system (tree with heavy duty come along/chain hoist works).. i use straps thru the manifolds mostly centered and lift the whole motor while a helper reports on the alignment tool feedback -

its fool proof. Ive had to add washers and all kinds of things to the rear but always got it perfect..

 

[frenchman Bob]

I have a Mercruiser 5.7L Bravo II 1997, in a 26 ft half cabin. This last spring I bought a new rebuilted engine (casting number 880, same as I had before) in Ocala FL. My mechanic and I installed it in my boat. After the installation, we found out the engine wasn’t straight with the boat. It had a small angle to the right, and the alignment bar was very very hard to push in and very very hard to pull out. The front engine mounting adjustment was good. We toke the engine out to make sure the flywheel housing was properly bolted to the bloc, and it was.We also checked its condition and nothing wrong with it. The transom plate has never been removed and it’s in very good condition. Anyone have any idea of what the problem is?

 

[frenchman Bob]

Thanks Bt Doctur and thanks CamaroMan, Both of your procedures make sens to me, but my mechanic don't agree, and HE IS THE MECHANIC and I'm not.. He says that the same casting number should fit where the other was. I'm afraid I'll have to do the final alignment all by myself. Thanks again

 

[Bt Doctur]

Have had more than one job where the coupler stripped and after installing the motor it was turned to the right . No apparent reason except the factor screwed up.with the engine mounting plate. Shifted the motor into perfect alignment and drilled new holes

 

[frenchman Bob]

Bt Doctur, When you say " except the factor screwed up" I'm not sure I understand what you mean. could you explain. You know, english is not my normal language, I'm french from Quebec Canada. Thanks

 

[achris]

sometimes the bushings sink in the rear

That's a sign that the mounts have failed, replace them!

- my best method is to remove ALL mount bolts - see where the motor is lined up, and shim as needed. Last 2 were a real pain and I did this and they are now perfect - alignment tool rotates with 2 fingers only.. Too many variables with rubber bushings, stringers sinking etc etc - i wouldnt redrill anything until i tried my method - its always worked.

You need a gantry or some system (tree with heavy duty come along/chain hoist works).. i use straps thru the manifolds mostly centered and lift the whole motor while a helper reports on the alignment tool feedback -

its fool proof. Ive had to add washers and all kinds of things to the rear but always got it perfect..

Merc have factored in the weight of the engine and how much the rear mounts will move. If you're having to 'shim'/add washers to rear mounts, then the mounts are failing, and the alignment will drift out very rapidly. And then you're replacing couplers. Fix the problem, don't 'band-aid' it.

Also, moving the engine while the alignment tool is in is an absolute MUST NOT! that's an even quicker way to destory a coupler than failing rear engine mounts.

Bt Doctur, When you say " except the factor screwed up" I'm not sure I understand what you mean. could you explain. You know, english is not my normal language, I'm french from Quebec Canada. Thanks

I think he means 'factory'... The factory screwed up and drilled the mount hole in the wrong place.

I agree with BT... REMOVE the lag screws holding the front mounts down, VERY slightly loosen the rear mounts, hang the engine from the lifting eye on the thermostat housing (let the rear mounts carry their full weight) and let the engine find it's own place. Then mark the new holes for the front mounts and that should have the engine in the right place. If it's still off to the left or right, then you may have a problem with the transom being uneven. It need to be exactly the same thickness all the way around where the transom plates bolt up... Or it'll show with a left/right alignment problem.

Chris.........

 

[Bt Doctur]

Cant find the pic but the factory has a template that hooks into the rear mounting holes and locates where to drill the holes for the front lags/bolts