Motor Loses Power

Box stock predator looses power after 15 laps in Main. Runs fine in 8 lap heats. No temp gauge. Any ideas as to what might be causing the loss of power?
 

DynoDon

Moderator
Next time it looses power reach over and shut the fuelb off at the carb. Be careful not to burn yourself on the muffler. Take it off the track and place a small container under the carb and remove the bolt that holds the bowl on. Make sure not to loose any of the fuel. Once you have all the fuel in the container remove the bowl. Hold your thumb over the bolt holes in the bottom of the bowl and pour the fuel back in the bowl. If the bowl is not well over half full, you have a fuel delivery problem. That is the first step in the process of elimination.
 
Next time it looses power reach over and shut the fuelb off at the carb. Be careful not to burn yourself on the muffler. Take it off the track and place a small container under the carb and remove the bolt that holds the bowl on. Make sure not to loose any of the fuel. Once you have all the fuel in the container remove the bowl. Hold your thumb over the bolt holes in the bottom of the bowl and pour the fuel back in the bowl. If the bowl is not well over half full, you have a fuel delivery problem. That is the first step in the process of elimination.
Thanks that is certainly worth a try.
 

flattop1

Dawg 89
Fuel seems okay...over half with some spilled.
The op stated well over half. Some being a relative term may want to repeat the test . Not finishing or running poorly ain't fun .
Something else is the vent line , as stated fuel flow .
Maybe test if it flows continuously for whatever time period 10 or 15 laps is in free flow .
Does it just slow down or pop and sputter or shut off ?
 
The op stated well over half. Some being a relative term may want to repeat the test . Not finishing or running poorly ain't fun .
Something else is the vent line , as stated fuel flow .
Maybe test if it flows continuously for whatever time period 10 or 15 laps is in free flow .
Does it just slow down or pop and sputter or shut off ?
The first week it was popping some after lap 15. Second week it just slowed down and seemed to be hot. Has anyone ever had coil problems possibly caused by heat?
 

alvin l nunley

Site Supporter
Sounds like it might be that your getting a little too hot, going a little leaner, causing a little more heat, causing a little bit leaner. Lots of things can cause you to get leaner. I would try a one size bigger jet and see what that does. I'm also thinking a colder spark plug. I'd try that 1st. 2 or 3 ranges colder would not be out of line. There's just so many things that can cause what you're describing!!
 
Thanks Alvin. Never thought about being lean. The motor was hot supposedly. Very hot summer night both times. Put new motor on and problems went away. No tach or temp gauge to know for sure:unsure:.
 
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