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Popping sound coming from engine at full throttle

D

dave5496

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"I have a 4.3L. Took it out to

"I have a 4.3L. Took it out today, started good, turning around 4600 rpm. Had to back down on the throttle and when I got back in to it, the engine would not get over 3400rpm and had a popping sound coming out of it. Any ideas what would cause this?"
 
You probley just flooded the e

You probley just flooded the engine. Does it still do this? Is it a carb or fuel injection? If its a carb sometimes when running that hard and backing off then hitting thottle again theres to much unburnt fuel still laying in carb or choke likes to suck closed a little enough to cause this. When you get a good back fire you sometimes blow the power valve on some carbs.
 
"[b]"the engine would not

""the engine would not get over 3400rpm and had a popping sound coming out of it. Any ideas what would cause this?"

Ayuh,....

Change the Fuel Filters,... It's going Lean...."
 
"yeah it still does it. the fu

"yeah it still does it. the fuel filter at the carb is new. the boat had a new engine put in it just before I got it, but I imagine its still the old carb. when ever I pull back on the throttle then push back into it the rpms go up to around 3800-4000 then drop back down like the engine is trying to speed up but won't. it also has alittle surge in it every now and then but not consistant. could a jet be stopped up"
 
"does it have points?? has the

"does it have points?? has the Timming been ck? Or how about the advancement weights for the Timming been ck out.

the carb needs ck out and a good cleaning, or just get a rebuild kit.. clean it real good and ck,, make sure all the setting or right with it.
Directions come with the carb kit.... for your engine specs.


Hope this helps out."
 
I'm going to run some seaf

I'm going to run some seafoam through the carb. whats the highest rpm I should run while hooked up to the ear muffs ?
 
"1500 rpm on muffs or neutral.

"1500 rpm on muffs or neutral.
You certainly have what sounds like a lean condition or fuel starvation and need to check anti drain back at tank, clear tank vent line,
and try sea foam but cleaning of carb inlet filter media or screen should also be performed.
If cleaner doesn't work then rebuild carb and set float levels using service manual and NOT rebuild kit instructions as they often differ.

Kurt"
 
"Where is the popping coming f

"Where is the popping coming from???? A good first step would be a compression test...also check the inside of the distributor cap for moisture, deposits or cracks...is it running on all cylinders at idle??? More information is needed to make an accurate diagnosis"
 
yes all cylinders are hitting

yes all cylinders are hitting at idle inside the distributer is dry and clean. and I pulled the filter on the carb and it was clean too. pulled all the plugs all were good. coil is new plug wires are new.
 
The fact that it surges speaks

The fact that it surges speaks of lean condition and most likely a dirty jet. Or has developed a vacume leak. Check carb base gasket and intake gaskets as well. (carb or starter fluid sprayed on these areas will cause idle change if leaking)

Kurt
 
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