1986 150 Black Max -Starter spins but doesnt engage

[Dennis G]

With one battery, it engages flywheel sometimes (gear spins but doesn't pop up enough). With two batteries, it does better but sometimes doesn't engage flywheel. Does better when engine is hot. Mostly, right now, gear spins but doesnt pop up to meet the flywheel. Ideas, please.
Update:
I put a reg car battery (temporary to try to start engine) in the boat. I havent used this boat for years (9). Battery is at 11.78 volts. No wonder gear won't rise. Battery is on charger now, but will buy a big marine battery for the boat this weekend.
I lubricated the starter gear and shaft. 1994 2002 Bayliner Trophy walk around 150 V6 Black Max

Update #2. Charged temp battery, installed new fuel line hit the start switch. It started right up. Starter gear spins and rises like nobody's business. Just needed a fully charged battery. Will install a new water pump. It's been sitting for a lot of years

 

[444]

I've got a 175 black max a few years older than yours and I found I had to pull off the starter gear and clean and lube it up or else it would randomly just spin but not pop up to engage the flywheel. Just something to know about and keep in mind.

 

[Texasmark]

Other thing is to remove all your high current wiring and clean up the inside of the contact area. That engine takes roughly 150 or so amps to spin up properly. 150 amps from a 12v source means that you essentially can't have any resistance in the circuit. Corroded terminals are resistance. Got a voltmeter? Put it on the starter 12v terminal and the engine block...nice shiny spot with no paint. Spin it up. If you don't read at least 10v you aren't spinning the starter fast enough to ram the Bendix into the flywheel....assuming it is lubed up properly and can run up the starter shaft. Do that and if you still have problems come back with what you have learned.