Popping sound in the carb.

[Mr. Crusader 83]

The other day I had the boat out. And at WOT the carb was popping.
I have changed the plugs that didnt look bad, also new cap and rotor. Cap wasnt bad, rotor was very black, and changed the fuel sep. Any ideals on anything else since I have not had time to take it out since?

[cfm]

Although could be ignition or carb don't rule out a bad valve or worn flat tappet cam lobe.

[Mr. Crusader 83]

Although could be ignition or carb don't rule out a bad valve or worn flat tappet cam lobe.
I did a comp. test 116-120 across the boards. also did a leakdown, and had no more then 7%

[Bense468]

Start with the easy stuff. spark, timing, etc. It could be powervalve in carb, and like mentioned could be worse stuck valve or cam going south.

[Mr. Crusader 83]

Start with the easy stuff. spark, timing, etc. It could be powervalve in carb, and like mentioned could be worse stuck valve or cam going south.
The fule sep was full of water. Almost sounded like the time I had water in my tanks.
Wouldnt a comp or leakdown test fail bad if it had a stuck valve?
And it only does it at WOT and its not constant. It will run fine then pop and keep going then pop again.

[Taylorman]

You make check your valve springs. I broke a spring once and it cause a popping sound out of the exhaust. You sure its from the carb? The exhaust valve was not closing all the way and the combustion would come out the exhaust. The water would muffle the sound. I shut off the water and ran it and holy shi* it was loud.

[BUSBY]

bad gas or a flattened lobe on your cam ...

[pw_Tony]

Yah if one of the Tappets on the cam has rounded off it could be holding an exhaust valve closed, so it has to go somewhere...

[Jet Hydro]

real fast test is to:
:idea: take off your valve covers then turn the motor with/out starting it and see if one rocker dosnt move as much as the others.
Look at your springs while the covers are off ;)

[Bense468]

The fule sep was full of water. Almost sounded like the time I had water in my tanks.
Wouldnt a comp or leakdown test fail bad if it had a stuck valve?
And it only does it at WOT and its not constant. It will run fine then pop and keep going then pop again.
Dump the fuel and throw some good fuel in it, take it out and see if it still happens. If it does, shut her down and go from there...OR
RUN IT

[BOBALOO]

If the gas is good and the ign is good, I would bet the valvesprings are letting the valves bounce a little. Popped thru the carb here and there but not at a regular interval. Had that problem before after putting a new cam in and reusing the springs that "should" have been sufficient. New springs and all was well.
Get rid of the water first though.

[pw_Tony]

Also once I had a spark plug break from the inside out. So all my compression was getting past the inside of the sparkplug. It made a -tick tack- noise kinda and would do it every revolution obviously. Then again you checked your compression already and you would have noticed that...

[jrork]

or a flattened lobe on your cam ...
real fast test is to:
:idea: take off your valve covers then turn the motor with/out starting it and see if one rocker dosnt move as much as the others.
Look at your springs while the covers are off ;)
Man, this brings back bad memories.... Watching the #8 exhaust rocker arm just wiggle instead of rock. :mad:
Crusader, the scenario you've mentioned is very similar to what I went through a few years ago. Pull the valve cover and take a looksee......good luck