Volvo-Penta S-Drive Problem

I have a Volvo Penta S120 S-Drive in my Olson 34 and its moving in reverse gear. If reverse gear is engaged and throttled hard the propeller will move up so much it hits the hull and gauges a groove in the fibreglass.

Clearly some kind of retainer or mounting bracket has either broken or come loose but if anyone can help point me to what this would likely be it would be very helpful.

Many thanks,

Simon.
Sapphire Star
Olson 34 Hull#39

Unusual Engine

A bit of searching on Google brought up quite a few hits, but mostly having to do with zincs and correct lube oils. There seem to be some changes in oil specs over the course of production.

There seems to be some traffic on these models on the forums at Practical Boat Owner, the large UK site.
http://www.ybw.com/forums/index.php

Presume that your prior owner changed the hull and engine installation over from the stock shaft drive. Among all of the owners that log in here, you may well have a one-of-a-kind engine installation. I hope that some of the mechanics that log in will have some advice.

Best,
Loren

Possible Suspension System Problem

Hi Loren,

Thanks for your reply. Surprised to hear the S-Drive is not common on the Olson 34. I'm thinking it must be something to do with the suspension system at the back of the S-Drive allowing it to rock forward under pressure thereby allowing the propellor to rise up about 4 inches. This is the drawing from my parts manual ..

Some photos of the potential problem

I took some shots today of the suspension fitting at the back of the S-Drive which clearly seems to be broken but I still cant see it being the only cause. My prop blade must be moving upwards some 5 inches approximately, which with the distance between the blade and this fitting would mean it lifting at this fitting by at least half of that.

sjconnor said:

I took some shots today of the suspension fitting at the back of the S-Drive which clearly seems to be broken but I still cant see it being the only cause. My prop blade must be moving upwards some 5 inches approximately, which with the distance between the blade and this fitting would mean it lifting at this fitting by at least half of that.

Click to expand...

Just to close this thread out - it was indeed the rear engine mount that had completely broken through. So in hard reverse gear the engine would be pushed forward and the s-drive lift up and propellor cut into the hull.

Now thinking back to a few years ago I recall once when the boat was being hauled out that they abandoned the haul out quickly to reposition the strap, and I suspect the strap could well have been on the prop, which may well have either weakened or broken the mount inside the boat.

A pretty simple replacement - (unlike the side engine mounts) and all has been well for a long time now.