Thread Tools Search this Thread Display Modes
Old 06-01-2016, 01:10 AM   #1
Join Date: Jun 2016
Posts: 1
Question Mercruiser 3.0L Knocking Sound


Just bought a Maxum Bowrider 1990 vintage with what appears to be the original engine (5000 Hrs) and on my first outing engine ran very smoothly but after about 20 minutes power dropped and a loud knocking sound came from the engine although it was still running. Engine starts fine oil pressure is good but when revving in neutral noise comes from the back end almost as if the fly wheel was loose or something broken ?

Anyone have any suggestions or have a similar experience ?

Kevin F is offline   Reply With Quote
Old 06-01-2016, 02:29 AM   #2
mmwjr's Avatar
Join Date: Feb 2012
Location: Perry Hall, Maryland
Posts: 6,145

Welcome aboard

5000 hours on a gas engine! Do you mean 500?

Coming from the back of the engine I would say gimbal bearing or joint however neither would cause a loss of power.

What oil pressure does it have? I'm thinking you may have lost a cylinder. Perform a compression test. If oil pressure is good then probably a rod bearing.
mmwjr is offline   Reply With Quote

engine, knocking, loss of power

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Powered by vBadvanced CMPS v3.2.3

All times are GMT. The time now is 07:37 AM.

Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2018, vBulletin Solutions, Inc.