3.0 popping noise

[rethredge]

My 1999 mercruiser 3.0 makes a noise at random when under a load at times. I have 3 videos on youtube of it running last week it made the noise some but not as bad as when under heavy load in mid summer. What is causing It?
Thanks,
Rome
http://youtu.be/1_LAyLfwbYk
http://youtu.be/1_LAyLfwbYk

 

[rethredge]

Re: 3.0 popping noise

Here's links to my other videos

http://www.youtube.com/watch?list=HL1332037840&feature=player_detailpage&v=A70PLxoxwn0
3
http://www.youtube.com/watch?list=HL1332037840&feature=player_detailpage&v=1_LAyLfwbYk

 

[rethredge]

Re: 3.0 popping noise

Here's links to my other videos

http://www.youtube.com/watch?list=HL1332037840&feature=player_detailpage&v=A70PLxoxwn0
3
http://www.youtube.com/watch?v=9X0xwTPA5vs&list=UUKqDRkegPAJS3VtyiiLwC_A&index=3&feature=plcp

 

[LilRedNeckGirl]

Re: 3.0 popping noise

its a bit hard to hear on the utube vids, but to me it sounds like a click. I would look at the belt driven attachments, @ alternator especialy. see if its heating up/ seazing momentarly.
typicaly, a "POP" is a carb backfireing for whatever reason, but yours sounds more mechanical. Easiest fixes are in the belt driven arena. try useing a broom stick pressed against your ear to narrow it down. put the stick end on each part of the engine in a SAFE location, then listen with the other end to your ear. that click will be easily located with this method most of the time. ( useing a solid wood stick of course, them hollow dollar store broom sticks just dont cut it. )

 

[rethredge]

Re: 3.0 popping noise

Thanks, I'll check that. I noticed that often when its making the click I can see fog coming from the engine through the tube that goes to the air intake. I think you can see it in one of the videos.