I have a slayer pro with a stock 3.3 that until the other day has run perfect,about 3or4 gallons through it. It would hit hard out of the corners, but on a long straight away it would run at what seemed like half throttle, sometimes it would kick into full power but only briefly. Checked everything, batterys good, slide fully opened,spur gear, richened needles leaned no difference. Engine never died, sputteredor sounded starved for fuel. Talked to traxxas he said it might be glow plug? I checked plug and it glowed bright, Ill put a new one in but I live in town and I cant get to my property for a few days, just curious what you guys think, out of ideas if this doesnt work, still got compression. I thought a plug either worked or didnt, ran 3 tanks throught it like this thanks for any input.

Glow plugs can exhibit behavior like this when they're starting to die, it's not uncommon. There's a rapid decline of performance between "good" and "bad", so swap it.

I had this happen twice in the last couple weeks on my 8ight. The first time it was the glow plug. The 2nd time I could never figure it out. Eventually, after trying everything else I unplugged the fuel lines from the carb and exhaust and blew as hard as I could. Not sure if something was blocking it or it was just coincidence  but its ran great since.

IMO...if u haven't fixed it yet. Check ur compression...U have 3 to 4 gallons on a traxxas 3.3....it might be get n tired...it's a rtr motor. I've run that motor for a long time..and u got ur moneys worth out of it ....unless u have been spot on with ur tune, the hole time. it might b at it's lives end...

I agree box her up and send her back to Traxxas!
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Ill have time tomorrow to try new plug, that doesnt work it will be trade in time, another 3.3 or a os21.  I ran this engine at stock settings and never had a problem so I thought  Id get a pretty long life out of it.  Checked fuel lines all looks good, I use compressor to check for leaks.

No, box it up and send it to the trash because it's RB TM523 or OS 21TM time!

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