View Full Version : Coupler failure with the 8.1L engine

09-27-2007, 01:20 PM
Has anyone else had their coupler fail from the torque produced by the 8.1L engine? I noticed, while cleaning the hull last week, that my propeller and shaft assembly would rotate a 1/4" left and right. It turned out the spline on the stainless steel shaft had worn out the mating spline on the coupler. Luckily my dealer replaced it for nothing and turned it around in just a few days. So, no big deal and I'll be able to boat to the USC / Husky football game this weekend.

I am just wondering if this is going to continue to occur every 6 years or so. Does anyone make a stronger coupler. I guess you probably don't want a stronger coupler becuase then the shaft would give out. My guess is the shaft is more expensive to replace than the coupler.

09-27-2007, 02:15 PM
The shaft in your boat was a double tapered shaft with 1/4" keyways. We introduced to MC went the double splined (splined at each end ) shaft in 03' (16 spline ). The splined shaft spreads the load over the splines increasing the strength.

09-27-2007, 02:23 PM

My boat (which I bought used) must have been upgraded with a splined shaft and splined coupler because that is definately what is in the boat.

So, anyone had problems with the splined shaft and coupler wearing out?

My '95 PS205 had the 1/4" keyed shaft but my 2002 has the splined version.