4.3 surging

[H20Rat]

So me being just slightly OCD about maintenance things, noticed something slightly different this weekend. While cruising along in my 1996 4.3l powered deck boat, I notice a VERY slight surging at partial throttle. When cruising around 2800 RPM or so on glass water, there was a barely perceptible surge at about 1 second intervals. It wasn't enough that my passenger, or the tach, registered anything.

Anything to be concerned about? I rarely get to run on perfect glass water, so it may have always been there. I haven't done any ignition maintenance on this engine yet, so sparkplugs are an unknown. (I've owned it 2 years)

 

[wahlejim]

I would say change those this winter or spring, but not the cause of the surging. How were you trimmed? It's possible that the prop could be cavitating ever so slightly, enough to cause an audible noise but not register

 

[Bondo]

Ayuh,.... Change the fuel filter, 'n see if there's any water in the old one,....

 

[H20Rat]

Boat is fairly stern heavy already so I almost always run with the trim all the way down. No cavitation. I swapped out the fuel filter when I got it, so it could use a change.