What happened

[sammythebull]

bought a pro max ran it ran good for a while turned 26/4 roy hill drag prop 6400 rpm 74 gps mph motor ate #5 piston rebuilt motor 6 new 015 pistons 90 gram stuffed pins milled heads 150 compression 1" spacer break in properly run at least 100 gal 93 trough it runs hot175/80 at 1100 to 3800 rpms cools at higher speeds4000+ 160 but the dam thing is slugesh and wont turn the same rpm or mph as it did before rebuild i just dont get it any body got any ideas as to what went wrong tps new temp sensor new injectors cleaned at rpm deisel ft laud.

[sschefer]

I probably shouldn't attempt to figure this one out but what the heck... My swag is it's either too much timing or lean. Both those will put you on the edge of detonation and that might be why your running hot and lacking power.

[sammythebull]

timing was set at 25, tps was reset which brought the the heat situation down into the 3500 rpm range it was getting hot at 4000 which was max rpm during break in time,checked plugs and pistons no signs of detonation is it possible that the 1" spacer plate is causing a low to mid range lean condition? it is between the injectors and the reeds weres a horn motor the injectors are behind the plate im thinking of removing the plate and see if that has an effect on conditions. reserch before rebuild indicated that the changes should have giving me a gain in power surly not a loss i will double check the timing and thanks for your input steve.