Stage 1 kit added, now it bogs down at top speed

bruin27

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I have an xtreme power 7hp motor that I just added a stage 1 kit, header pipe, intake, new jet, new spark plug. Everything is great at low rpm, once I get towards top speed it starts fluttering. Didnt have this issue before the stage 1.
 

Karttekk

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Did the new intake come with a better air filter? If you're using the original air filter you aren't pulling in enough air to match the additional fuel flow. I put an UNI air filter on a kart recently that included a larger jet. The additional air would have leaned out the fuel too much.
 

madtom

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Is it possible your floating the valves?
Was the stage 1 kit specific for this motor? Most stage 1 kits come with a #36 jet stock jetting is normally a 28 - 32 believe. Not sure if a 38 would cause it to bog or spit. Granted these number are for a 212 but I doubt there's much difference

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bruin27

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Heres how it looks. The kit is for the predator 212. Everything fit fine, basically the same sizemotor. .
 

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madtom

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Is you governor still enabled or bypassed

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madtom

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Maybe with the new jetting you're just hitting the rpm limit engaging the governor

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BigWes

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I agree with Madtom. You probably now have enough fuel and air to get your engine up against the governor. If not that it could be floating the valves...I had a hemi that would do this with a stage one...I don't know why but it would. Or, it could be running the fuel out of the bowl faster than the tank can gravity feed it back in. I had one do this as well. It was the result of a dirty tank screen which I replaced and also replaced fuel line and cleaned out the fuel shut off valve. It had some buildup in it as well. Good luck.
 

Brianator

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"Fluttering" is a sign of a lean condition and most commonly referred to when speaking of 2 strokes, it almost sounds hollow in a sense.

Maybe with the new jetting you're just hitting the rpm limit engaging the governor

Not only is the governor always active but it's job is to maintain rpms not limit them so I feel you're a little off base there...



Chances of hitting valve float within governed speeds is slim to none.

What's the spark plug "say"? When it's "fluttering" hit the kill switch , give it a chance to cool down a bit and remove the plug to see what it looks like (feel free to post pics).
 

bruin27

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"Fluttering" is a sign of a lean condition and most commonly referred to when speaking of 2 strokes, it almost sounds hollow in a sense.



Not only is the governor always active but it's job is to maintain rpms not limit them so I feel you're a little off base there...



Chances of hitting valve float within governed speeds is slim to none.

What's the spark plug "say"? When it's "fluttering" hit the kill switch , give it a chance to cool down a bit and remove the plug to see what it looks like (feel free to post pics).

I'll take a look tomorrow and post a pic, I dont think its the governer either, it feels like to wants to die when I get close to top speed, then it picks up, then starts bogging then recovers over and over, I'm only hitting like 32mph, I have a heavier kart with the same hp motor stock getting 35 so something isnt right.
 

BigWes

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I'll take a look tomorrow and post a pic, I dont think its the governer either, it feels like to wants to die when I get close to top speed, then it picks up, then starts bogging then recovers over and over, I'm only hitting like 32mph, I have a heavier kart with the same hp motor stock getting 35 so something isnt right.

sounds like it's starving for fuel when it is running wide open, check into what I said about that. You may need to put a pump on it, but first make sure the tank screen is clean and it's getting good flow from the tank into the fuel bowl.

As far as what he said about valves not being able to float on a stock engine I will disagree with that, especially on the hemi. Maybe the stock springs just suck but just know if you replace the springs with some aftermarket 18# springs a lot of the wide open throttle issues go away...just saying. I just replaced a set of stock springs on a Briggs clone engine this weekend and the difference was profound. But I did have the governor completely and properly removed.
 

bruin27

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sounds like it's starving for fuel when it is running wide open, check into what I said about that. You may need to put a pump on it, but first make sure the tank screen is clean and it's getting good flow from the tank into the fuel bowl.

As far as what he said about valves not being able to float on a stock engine I will disagree with that, especially on the hemi. Maybe the stock springs just suck but just know if you replace the springs with some aftermarket 18# springs a lot of the wide open throttle issues go away...just saying. I just replaced a set of stock springs on a Briggs clone engine this weekend and the difference was profound. But I did have the governor completely and properly removed.

I have great acceleration when I mash the gas, really quick, only when I start to reach top speed it starts sputtering.
 
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