Engine Popping Noise

[pennyduke]

Can anyone tell me what this noise is?

http://s175.photobucket.com/albums/w121/dflynn1136/?action=view&current=IMG_0897.mp4

 

[achris]

Re: Engine Popping Noise

That was about 1 knock every second, the engine was doing about 600rpm, which means a knock every 10 revs... so nothing engine, or it would be more frequent... drive gears are 1.5:1 (20/22 teeth), so each tooth meets the same tooth again every .... 10 revs...

Pull the drive and see if it still does it... One of the things it could be is a tooth missing in the upper drive... Removing the drive will isolate it... Also pull the plugs and do a compression test and 'read' the plugs... You can garner a lot about the combustion process from the plug firing ends... When you pull them, keep a note of which pot each plug belongs in...

Chris.....

 

[makonnen]

Re: Engine Popping Noise

What he says. Good advice.

 

[pennyduke]

Re: Engine Popping Noise

The boat is in the water at my slip. Should I do the compression test first or haul it out and pull the drive? It really sounds like a popping in the motor somewhere.

 

[achris]

Re: Engine Popping Noise

Do the compression test, that's easy... Then haul it out...

 

[Idlespeedonly]

Re: Engine Popping Noise

Kinda sounds like a backfire. You can pull plug wires on at a time and see if it goes away.

 

[achris]

Re: Engine Popping Noise

Kinda sounds like a backfire. You can pull plug wires on at a time and see if it goes away.

It's too regular and, at the end of the video as the engine speed increased, changed exactly with the engine speed... It's not a backfire..

Running the engine with a potential drive problem like that could easily lead to damaging other things. If the drive completely lets go it could lock up and destroy the coupler, not to mention that all the metal from the top box will drop down into the lower and render that useless too.... Pull the drive and fix it.

 

[pennyduke]

Re: Engine Popping Noise

I'm all for not blowing something up. I will pull it out Friday and report back this weekend. Thanks for all the help...