81 mercruiser 120 cavitation or out of gear?

todster

Cadet
Joined
Jul 20, 2007
Messages
29
Out on lake today. Boat ran good. Would pull tube and plane with no problem.
I noticed if I pulled back on throttle below 4k rpm after getting on plane, that if I rapidly move throttle to WO it acted just like it was slipping. I thought at first that the coupler broke. But yet out of the hole it was solid pulling a tube with 2 people on it, it was only if I increased power to fast after getting on plane. Thinking now it wasn't like it spiked rpm's either just acted like no propulsion, if I pull throttle back and start to drop off plane then go back into it I was fine. Dark now but tomorrow will drain a little oil off bottom and look for metal. If it was jumping out of gear one would think it would bang or clunk. Also is it normal for the outdrive to have a whine sound to it when moving along, kind of like sound from running in first gear with straight cut gears? The right angle gear box on top was very warm but not hot. I could hold hand on it. This is my first outdrive and first boat motor that isn't older than myself. It also has rattle like exhaust shield on car at certain rpm @2500 or thereabouts. Almost like housing around coupling rattling.
 

todster

Cadet
Joined
Jul 20, 2007
Messages
29
Re: 81 mercruiser 120 cavitation or out of gear?

Checked oil and no metal in it top or bottom. It had water in oil but the guy before hadn't put oring in port in lower leg. It just has 80-90 GL4 in it right now but now that I know it isn't taking on water I can put some good Synth in it. Marked prop to check it for spin but weather aint so good right now to test. Almost thinking blow out, if the prop hub was spinning it seems like it would do it more so when I have the max torque on it trying to get a tube up?
My rattle at 2k stops if I hang onto starter tightly. Bolts are tight so why?
I replaced the gimble bearing but just popped the bearing out of the retainer from the new one and slid it in to old one. Was that a mistake?
 
Top