Help! My 200 HP A23-34 is stranded! The starter spins, but the engine won’t turn over. Can I fix it? Should I get a new lightweight starter? The Sky-Tec?
Your symptoms are most commonly caused by a failed Bendix drive, or by one that is binding in oily crud on the starter shaft. This assumes that you have the original Prestolite starter. When you look at it, if the teeth are engaged with the flywheel, and are not broken off, you have a failed Bendix drive. If they are not engaged, it may just be gummed up, as the Bendix relies only on inertia and momentum force to engage and disengage.
You can’t legally repair it yourself, if the Bendix is bad; nor can you legally replace it yourself. Unless, of course, you are an A&P.
You legally can try cleaning it yourself, if the Bendix is not engaged. Buy a can of electric motor cleaner (not brake cleaner or engine cleaner), and some WD40. Keep spraying the cleaner up into the splined joint between the Bendix and the shaft. Then try to pop/pull the Bendix forward into engagement with the flywheel, and spray it some more until the cleaner runs out. Then soak it good with the WD40.
Note that if you get the Bendix engaged (when it previously was not), you will probably be able to start the engine. You do need to make sure that the Bendix disengages properly after the engine fires. This will mean having someone looking and listening from outside, where the spinning prop will be very dangerous. The safest thing to do is to perform the cleaning and testing with the cowling off, then shut down the engine to re-cowl it following a good test. Of course, this might mean having the problem recur. You must not fly the engine with the starter still engaged.
Note that the Lycoming recommendation is to keep the starter shaft clean, and sprayed with Silicone spray. The Silicone is fine if it is applied at least every 50 hours, and if the engine is not leaking oil into the starter shaft. In my opinion neither situation holds true very often. I prefer the lightweight starters with the solenoid-based drive engagement. Having said that, the 12LS SkyTec will not survive on the 200HP IO360. The starter itself holds up fine, but the sharper vibration pattern of the IO360 will cause internal fretting in the solenoid. I have gotten from 185 to 450 hours on the 12LS solenoids. If you go this route (which is the least expensive, for a lightweight starter), I advise that you carry around a spare solenoid. While technically not legal for a non-A&P, they can be easily replaced with the starter still on the engine. Sky-Tec has two other options; the HT and the Inline. I have been running the HT for a few years now, problem-free, but I do not yet have a long enough service history to say for sure how it works out. I think that there is another lightweight available. I do not recommend the Lamar-Prestolite ‘lightweight’ starter, as it continues to use the Bendix drive engagement. If you do a BAC search on Sky-Tec or starters, you’ll find much more info on the subject.