270 Outdrive Will Not Engage

[NateW]

1980 Bayliner Explorer
Volvo Penta AQ120B
270 Outdrive

I picked this boat up this summer and it has been a great teaching experience for my children on settin points, rebuilding carbs, impellers and the general oys of boat ownership. I also taught them to ski and when it was finally my turn to show them how it was done the boat lost power to the outdrive after pulling my up. Any thoughts or advice on how to narrow down the issue are greatly appreciated. I’ve scoured existing threads and come up with a few questions based on what I’ve read so far.

Background:

• Engine runs great but the throttle no longer engages the drive at all in forward or reverse (previously worked as expected did though with a clank I attributed to idle speed)
• Shift cable mechanism looks good (cotter keys there, responds to throttle movements in both directions). I was convinced this was the issue till I popped off the 270 Cover Plate
• There is a “bell housing” at the back of the engine that meets at the transom so I cannot see the “coupler” I’ve read about
• There is no noise, resistance, really any indication I’m trying to engage forward or reverse
• Propeller doesn’t move at all on dry land, it isn’t a spun prop

Question 1 – I’ve read about the eccentric piston and making sure that is working but don’t really understand it. It looks like a (fixed) mechanical device that pushes a cone up/down. I’m not sure how to trouble shoot it. Steps for how to identify an issue here are appreciated. The fact that no noise is emanating from the stern drive is making me think this could be the issue.

Question 2 – if I blew the u-joint I wouldn’t it clank or otherwise make some noise when I engaged the gears? It doesn’t look like there is enough room for non-interference fit so feel like this isn't the issue

Question 3 – could I pull back the drive bellow to see a spinning shaft to conclusively confine the issue to the upper gears (remove “coupler” from as potential source of problem)

 

[kenny nunez]

You may have a bad hub in the propeller. With the engine off put the shift in forward and try to rotate the propeller. If the propeller rotates and the retainer cone nut does not move then that is the problem. The only other part on a Volvo drive that can break without noise is the lower vertical shaft just below the spline coupler that couples the upper to the lower.

 

[NateW]

Kenny, I poked around some today and here is what I discovered.


Here is what I did

• I disconnected the cotter pins to separate the shifter cable from the outside of the eccentric piston and manually shifted the boat into gear. I was able to spin the prop in one direction but not the other; the opposite occurred when I manually moved the piston to the other direction. This made me think I "fixed" it simply by freeing the piston.

• I removed the eccentric piston and looked around. No apparent damage to shoe, upper/lower gear, metal filings, or anything to indicate an issue there.

• With eccentric piston removed I spun the prop while holding the brass cone and wasn't able to stop the cone from spinning. Furthermore, if I manually pushed the cone up/down if would engage the gear and prevent me from spinning the prop. I don't think I sheared the shaft of the coupling.

• I "bunted" the engine with the piston removed but didn't see the upper or lower gear advance. This made my heart sink a little. I think the u-joint is gone.

• I buckled it all back up to test it reassembled hoping that somehow it worked. I started the engine, inadvertently with it up, and when tilting the motor down it made some horrible clanking noise, I think this is the u-joint banging around.

If you have any other thoughts / ideas to get to the root cause I’m all ears. If not, I’ll review some manuals, order parts, and cross my fingers. If there is “how to” thread or video your aware of that compliments that manual by all means point me toward it.

Thanks,
Nathaniel

 

[kenny nunez]

Remove the hardware that mounts the helmet to the upper gear case. There should be some small threaded holes 1/4” 20 which are used to back the anchor slug out of the receiver. Drain some of the oil about a 1/2 cup. Remove the rear socket head bolts and the 2 nuts on the side of the gear case. Remove the 2 worm clamps and push the bellows forward, pry up on the area @ the 6 o clock area where the bellows was, lift and twist the gear case 180 * then pull it back. Be careful for sharp edges. Try to post some pictures.

 

[NateW]

Thanks, will provide updates when I tackle this project. Will be a few weeks before I can get to it.

 

[kenny nunez]

IN the mean time be sure to acquire a genuine Volvo AQ 270 service manual.