One of the biggest mistakes I've made was when I purchased a 2007 Stingray 180 RX Bowrider boat with the Volvo Penta SX I/O drive.
For decades, almost all I/O power trims used an in-the-boat hydraulic reservoir and pump assembly to raise, lower, and trim the out drive. There was little to no issue with this arrangement.
Volvo Penta, for some reason, decided to violate a key engineering rule -- if it ain't broken, don't fix it! Volvo placed the so-called maintenance-free system outside the hull and below the waterline in the down-drive shroud. I supposed that if the supporting engineers who designed the unitized system did a good job, there wouldn’t be an issue -– but they didn’t. The unit is fully below the waterline, requiring out-of-the-water inspection and filling. The unit housing is made of a fiber-reinforced polymer that had a dissimilar polymer plug ultrasonically welded in place.
Most of the poly engineers out there are already grimacing. Dissimilar polys do not like each other –- and they don’t heat-weld well. It was leaking into the Ohio River. Volvo, after many months of listening to my complaints, replaced the defective $800 unit with another defective unit. And guess what? It’s leaking again.
Another issue with the system is the high-pressure hose connections for the trim cylinders at the pump assembly –- again below waterline –- are a flanged, 3/16 pipe with two O-rings retained by a retaining clip. There is no threaded, tapered, or compression junction –- and those leak into the river as well. This is the current production Volvo system. The rest of the SX is great, but without trim, it’s worthless. I should have bought a Mercury.
This entry was submitted by D. Randell Greer and edited by Rob Spiegel.
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