Align Centraflex M Coupling

[dgadee]

Trying to find out how to align a Centaflex M-type:



Have contacted firm a couple of times but no reply and not sure I understand some of the instructions I have seen in older posts on the forum.

Do I attach the coupling to the gearbox and then align shaft? Or attach coupling to shaft and align in the more traditional way?

 

[Pagetslady]

I used the old fixed coupling to line the prop up then removed it and connected the Centraflex secured the shaft and it's been fine for the last 25 hrs motoring. You could of course check again with feelers, by easing off the fixing bolts as you would with a fixed coupling.
Mike

 

[dgadee]

I used the old fixed coupling to line the prop up then removed it and connected the Centraflex

Can't do that - it's a replacement engine rather than a replacement coupling.

 

[alahol2]

If there were no instructions to follow I would bolt it onto the gearbox flange. Line up so that the prop shaft will slide easily in and out of the coupling then bolt up the coupling. After that you are into feeler gauges at four points as you rotate the prop.
My much simpler Centaflex coupling has a red painted bolt specifically for use with a feeler gauge to finalise alignment.

 

[doug748]

Probably the easiest way is to attach the coupling to the engine and clamp a spare length of propshaft into it so it sticks out 6in or more.

Centre the real propshaft in the stern tube by use of a spacer tube or old cutless bearing, from within the boat, in such a manner that the shaft can be advanced to meet your bit of steel sticking out of the centaflex. A steel rule across the top of the two will allow you to judge the height and angle of the engine; and from the side will betray any problems in the horizontal plane.

If done with care this can be accurate enough for the centaflex. It can be checked with feelers but, for a variety of reasons, it is not particularly reliable with this set up.

One forum member has fitted many of these to Albin Vegas and said that, when properly done, the propshaft could be pushed from the prop end and engaged into the centaflex with no assistance and an audible "double click" as it slid into place.
If it fits cleanly and turns easily, that should be that.

 

[syTaika]

I replaces my prop shaft and the coupling a couple of years ago. First I attached the Centaflex coupling to the engine and then an aluminium tube to the coupling. Next I adjusted the engine so that the aluminium tube was centred to the stern tube and the p-bracked without the cutless bearing. Finally I installed the prop shaft and the cutless bearing. Seems to be accurate enough.

 

[Poignard]

If there were no instructions to follow I would bolt it onto the gearbox flange. Line up so that the prop shaft will slide easily in and out of the coupling then bolt up the coupling.(...)

That's how I did it. That was in 2002 and the engine has not been out since then so I think it's a satisfactory method.

 

[essexboy]

If you look up the Vetus version the instructions are all there. The bolt torques appear to be somewhat critical, as does thread sealants.

 

[dgadee]

Many thanks for the advice.

 

[Jesgatt]

Hi. I know that this post is a bit old, but I am trying my luck for a reply . I replaced the engine mountings and tried to undo the nuts of the centraflex from the gearbox, but two of them are impossible to unscrew due to the tight space and I don't want to risk to ruin the nuts. Do you think that if I remove the shaft and try to align it to its place again, will be enough? The boat is in the water. Thanks

 

[dgadee]

Did you replace mounts with shaft in place? Not sure I understand.

 

[Jesgatt]

Yes, I used supports and inflatable jacks to hold the engine in place. I disconnected and replaced the mountings one by one. The engine is a yanmar 2gm20 and the mountings can be disconnected from the engine bracket without lifting it.

 

[dgadee]

You can remove the shaft from the coupling? If it slides back in, I believe the engine is aligned.That means shaft and its socket are all correctly set.

 

[Jesgatt]

There is a few mm of alignment needed, hopefully there will be no issues. I left the shaft disconnected from the taper cone, so that the mountings will take shape. Planning to do it in 2 days time. Thanks