Engine Alignment

[Steve S.]

I seem to have an alignment problem.  I've read all the advice on the board about how to align the engine to the shaft, but I think it may not quite apply.  I have a plastic coupling on the shaft.  It's not a bullflex.  It's a solid red plastic coupling which is supposed to snap and break if the prop experiences severe stress while in gear, thereby saving the tranny from damage.   Put on by PO and I don't have the brand and type.  The shaft appears to enter the flange properly and fits very snug and when I turn it manually there doesn't appear to be any play.   However, when I put the engine in gear, there is clearly some vibration.  More than when the engine is out of gear.   OK here is my question:  Is it the space between the shaft and the inside of the coupling that needs to be within .003 of an inch?  Just where do you measure?

[Ron Hill]

Kuching : What you're looking at is called a "Driver Saver" - it's NOT a flexible coupling.
To check shaft alignment you need to take it off and mate the round metal coupling on the shaft directly to the 4 "studs" on the transmission. It's the (no more than .003") spacing between those two pieces that you need to check for.  Also make sure that your spacing between the front of the prop hub and the aft end of the strut is no more than 1".
Hope this helps.  

[Pat df]

Hello,
  I am searching this site for  information about the C34 in which I am interested in purchasing. I have owned a C30 for several years. If the C34 have basically the same setup as a C30 ( I have not seen the power train of a C34 ) I will tell you how I did mine. First of all my did not have a coupling, when you align the shaft the measurement you want is between the flanges. You take out the four nuts and bolts holding the two flanges together then seperate them, ( that's a little task in it self ). When you seperate the flanges you will see that in the center it is made so that they will self align but will rotate to align the bolts. What you need to do now is push the flanges back together without the bolts and measure 360 degrees around the flange, that's where you do not want more that .003 inch at any point. You basically want the two flanges to mate perfectly flush without any bolts holding them together. How you align the flanges is with the motor mounts, say for instance you have .006 inch between the flanges at the very top ( 12 o'clock ) you may have to raise the front of the motor to close up the gap, if the gaps at 3 o'clock you may have to slide the port side forward and the starboard side backwards. In the perfect situation you want the shaft to have perfect alignment with the cutlass bearing, stuffing box and mate  flush with the transmission flange, so there's no bow in the shaft, or undo pressure on any part so the shaft spins true.  It's time consuming but I got mine down to .001. I hoped that helped and I hope the C30 and C34 are the same setup. If they are the same and you need any more help please ask.

                                             Happy sailing,

                                               Pat

[Steve S.]

Thanks to all, that clears it up.   I've been staring at the driver saver coupling for a long time wondering how to work around it.