Pulsing at wide open throttle

[chrisbbee]

People 150, At full throttle I am getting a "pulse".  Runs good but once I get up to speed it bogs down and then back up.  It is acting like I am shuting of the ignition and then turning it back on.  It Only does this at higher speeds at 80% throttle and above.  Anyone had similar issues?
Thanks in advance!
Chris

[sidthesloth]

Check w your fuel filter, may be blocked.

[JustWantToRide]

Also check the condition of the gas line.  Make sure that it isn't getting soft, doesn't have any kinks, and isn't getting squished by anything.  Try topping off the tank.  Sometimes the extra pressure helps when there is something restricting the fuel flow.

[sidthesloth]

Also check the fuel cap vent is not blocked.

[chrisbbee]

Fuel cap is venting properly, fuel filter is clear, needle and seat are working properly and are clean. Fuel system is looking good so now I am starting to consider ignition. Full throttle at lower rpm seems fine. I have heard of coil problems and if I can track one down I might try that.  Any thoughts? Thanks again

[fshfindr]

I would still replace the fuel filter.

[chrisbbee]

Fuel filter is clear, I even tested it by pulling the feed line off the carb and putting vaccume to the fuel shut off and checking flow....... in typing that, I just thought i might apply vaccume to the valve and take if for a spin.  If the valve is not getting enough vaccume at wide open throttle it may be shutting off.... I will try it tonight and see what happens.  Still, any more thoughts would be appreciated and as always thanks in advance!

[sidthesloth]

If you are satisfied that the fuel system is good, that leaves electrical and mechanical. If you can, try replacing your cdi or coil, one of those could be breaking down. It could also be that you are reaching the max engine speed that the cdi will run at, maybe a worn belt causing the engine to run too high rpm?

[cobrar1]

The same thing was happening to my Agility 125 and it turned out to be a loose spark plug wire. Where the connection is from the wire to the spark plug was not tight so the vibrations was causing the spark plug not to fire. I go a new NGK plug and wire and that fixed it for me. At very top throttle at high speed it still might cough at me, but its rare. I just back of the throttle a fraction and its all good from there! Give that a try and see how good the connection is with the threads on the spark plug and the wire.

[chrisbbee]

The spark plug is brand new and the connections all look good.  I still have not applied vacuum to the fuel valve but I am going to try to get to it tonight.  It is weird, the longer I hold it at full throttle the more it happens.  I thought about the possibility of over-reving the motor but last year it didn't have a problem with the "high" speed.  Right now it will not go over 50.  It is just acting like a fuel starving issue.  If I back off a little for a min I can rev it back up for a few seconds before it starts dying off again.

[JustWantToRide]

Full throttle at low rpm is fine, full throttle at high rpm is not.  I think the sloth's suspicion of the CDI is worth looking into...

[sidthesloth]

Getting worse the longer it is held at full throttle sounds like a restricted fuel flow, worth checking filter and in tank screen.

[SteveM]

Try adding some Seafoam to the fuel and see if that helps.

[thebatman]

Could his float bowl be getting empty and can't keep up at the high rpms? OR to small a filter??
I do also side with the sid on checking the coil,cdi.. Seems several ppl have had odd issues that went back to the cdi

[Drnilly007]

I also had this problem a few hours later the belt snapped. Check the belt.