1992 115hp mercury noise

[yap-yap]

driving at 4000 revs sudden noise like loose part (metal sound)stoped and checked all looked ok, restarted no problems but noise remained.
At home started with ears on,no noise (no water pressure on prop)
Should I be looking for a bearing problem or broken part in the gear box or some other problem in the lower unit (gear box)

 

[Faztbullet]

Pull the oil drain screws and see if oil has metal or water. Next run a compression test as these motors like to break skirts on pistons...

 

[yap-yap]

Thank you.
Noticed a lot of water coming out of the tube that motor is hinged on ??(above cavitation plate)

 

[yap-yap]

carried out compression test , top cylinder 120 2nd 105 3rd 90 4th 115..
do you think 3rd is a problem ?

 

[Faztbullet]

Pull exhaust cover and you can inspect piston and cylinders....

 

[yap-yap]

Thanks for the advise

 

[Texasmark]

Merc serv. man for that engine says "If compression is less than 120 expect problems......it is. Also you have a large variation between cylinders which indicate problems. Usually 5-10% variance max (depending on whose talking) between cylinders is what you want,,,,,course you have to assume that the test method for each cylinder is identical and not accidentally injecting an error.

Pulling the cover as FB said may show you what you are looking for.

On the lower unit, doesn't hurt to do that too. Leave engine vertical for a couple of days without running. Pull the drain screw and pay particular attention to what comes out first and the color of the oil. Also pay attention to the magnet on the drain plug. If loaded up with metal shavings, bad news, if water comes out before the oil, bad news, if oil is yellowish in any way bad news.

 

[yap-yap]

thanks