It seems many boaters place more importance on regular engine oil changes while foregoing crankcase maintenance. The lower unit foot grease is equally if not more important. All the power from the engine is transferred to the lower unit which is always under water and the quality of the grease is the only thing to prevent over-heating of the metal-on-metal components. I change out my lower unit grease each time I change the engine oil. Its cheap, easy and doesn't take long.
As a testament to my maintenance and operating practices, my flounder boat (a 24' jon boat) has the original, 2000 Honda 90 outboard motor on it now with 2786.0 hours on it (i just checked 10 min ago). I think the harder the outboard is run the more stress is placed on every part of the motor and so I rarely run at wot, and then only for a very short distance and usually at 50-75%.
What's interesting is that, on a charter, i use the Honda 90 only 15 - 20% of the time, for getting to and from the gigging grounds where I turn off and trim up the Honda and use a lawnmower air motor engine with an ultra-light composite propeller to cruise an average of 12" of water while searching for the elusive flounder which have the ability to hide-in-plain-sight.
While the work-horse flounder barge / Honda 90 are used to grind out charter after charter in the backwater (with an aluminum prop), the 19' C-Dory Angler is my beauty queen with her 2008 Suzuki 90 (stainless prop) thats gets towed with a Lincoln Navigator and never the the humble 94 Dodge Ram used to pull the Flounder Barge. My C-Dory is used sparingly for personal (non-chartering use only) deep water river cruises to nearby Cumberland Island. I use only non-ethanol gas and flush the motor after each after each use with dual-flush outboard motor ears.
Speaking of maintenance, last month (Dec, 2019) I took her (the Blue Moon) to the factory-authorized Suzuki Dealer for a complete maintenance upgrade to all consumable (genuine Suzuki not after-market) parts and fluids: New oil, oil filter, two new fuel filters, a brand-new water pump (complete kit not a rebuild), lower foot grease, new fuel pump, new spark plugs and even all brand-new (not rebuilt or just cleaned) fuel injectors. Proper and complete maintenance means a long outboard life with many years of happy boating memories.
While there the Dealer pulled the ECM computer data with the engine hours being in the low 400's. A compression test was done with all the cylinders being 119-120 which they said was comparable to a brand-new engine.
Regarding the broken spline if using one's boat in the backwater I feel like an aluminum propeller is a must. The propeller will bend or break instead of transferring the shock directly to the shaft as with a stainless propeller. Its easier and cheaper to either replace the aluminum prop or in the case of minor bending use some pliars to straighten and a file or grinder to smooth it out.
Well thats my rant and advice for the day. Sorry if I rambled a bit
