ok i know cussbud & since he's having PC problems i'll help you out. His GRP engine has been broken in with 30% & will run with it. The tune is ridiculously hard to find so it's never been ran at 100%. Now due to local hobby shop not stocking 30% we have to go down to 20%. Problem is it will not start with the 20%. We even went back to the factory settings & nothing. However another club member we know got his GRP to run on the 20% but again the tune to hard to find. Both GRP are idential, both broken the same method. The plugs are GRP turbo #4 which is a hot plug. I'm a bit loss as to what to try next.