Mercruiser 43LX Alpha1 gen 2 tapping noise from the flywheel area

"1993 mercruiser 4.3LX Alpha1

"1993 mercruiser 4.3LX Alpha1 gen2, has a tapping noise that increases with rpm in the flywheel area. Was hard to steer and then engine bound up at dock the next day. Burnt starter as engine tried to turn over but had a bind. Installed new starter and after a few trys bind broke loose and engine turned over and ran fine. I had been turning engine by hand but it was difficult to turn. Engine runs good but has a tapping noise at the flywheel area. It almost sounds like a piston rod slap. I pulled the outdrive and fluid milky with no metal. Big gimbal rubber seal broke into chuncks and was in the bellows. Water was also in the bellows. I am able to turn the gimbal bearing with my fingers. The ujoints look fine and move freely. The engine still tapps after I removed the outdrive and ran engine with water at inlet at thermo housing. . What else could be tapping aft of the rear oil seal? I know i got to replace the gimbal bearing, ujoints and seals."

"Not much there but some core

"Not much there but some core plugs, flywheel, flywheel studs, coupler bolts, coupler. May need to pull the engine to find out."

"Thanks. The boat shifts and r

"Thanks. The boat shifts and runs fine. A bad coupler means that the boat slips? Also, the splines look good inside the bellows. Just some water and grease. The drive shaft looks good also."

"Ayuh,... I'd sooner thin

"Ayuh,... I'd sooner think a Bolt or 2 has backed out,+ is causing the Problems..."

Thanx bondo! Im gona pull the

Thanx bondo! Im gona pull the motor and check things out. It seems to be pretty straight forward. All I need is the alignment tool to put tit back! Any other words of advice?

Pulled the motor and no bolts

Pulled the motor and no bolts had backed off the flywheel. There were 2 teeth broken on the flywheel. Beats me! I dont think that would cause the tapping noise. Everything looks good. Can I run the engine on the hoist before I put the engine back in after I replace the flywheel?

I guessing a bent rod caused b

I guessing a bent rod caused by hydrolock when I tryed to start the engine originaly. This also explains the 2 broken teeth on the flywheel. Im gona do a compression check and start the motor on the hoist. Any words of advice?

ok...I just ran the engine wit

ok...I just ran the engine with flywheel on and coupler off. The tapping is still there. Hard to isolate. Im gettin ready to do a compression check. There is also a small amount of water in the oil. Not quite milky but its there. Any ideas!

Compression test
1 175
2

Compression test
1 175
2 170
3 155
4 175
5 170
6 130 140 with oil squired in cylinder

Removed valve cover and has some milky puddles especial near #6. Ran engine with starboard valve cover off and she fired right uop and idles great. Still had the tapping sound so I put finger pressure on each valve stem spring and lifter rod to see if noise went away. It didnt. Looking like a #6 rod or piston tap. Im out of things to do short of droping oilpan and removeing head to remove piston? Maybe I should just by a short block and put it in!

This leads me to the question

This leads me to the question if I should install a new piston and rod in #6? Been many years since I rebuilt an engine. Is it possible to install piston and rod from the bottom after I drop the crank a little?

"Maybe I should just by a

"Maybe I should just by a short block and put it in!"

Both heads need valve work. Why not go w/a long block?

Thanks Guy!! Thats what i was

Thanks Guy!! Thats what i was thinking. Might as well just put a new long block in it and be done.
Just for my info...why do you think the heads need work?

"The compression numbers, age

"The compression numbers, age and I would want a valve job, new valve guides, roller rockers, etc. and the heads milled for a true fit to a new block face."