You are doing the right thing by checking the numbers on the starter with power master..Please tell them what style block you have and have them cross reference what starter suppose to work with that block which i do not think would matter but at least exclude this as being a potential problem...when i have these type of toe stumping problems i try to isolate the issues..example
1- its got to be the wrong tooth flywheel
2- got to be the wrong starter for the fly wheel /block.
a couple of more questions..
1- what tooth is your flyweel?
2- what is the bolt pattern on the block (starter location) staggerd or standard
3- is the motor internally or externally balanced?
4- have you tried to pull out the starter gear with a pair of needle nose pliers etc...
they (powermaster) makes this starter for 2 different flywheels..#1 168
tooth (part#9500) #2 153 tooth (part#9502)
if you have a 168 tooth starter on a 153 tooth flywheel then that could be your problem.
this problem can be worked out i assure you..its gonna end up being something simple such as a wrong part etc....but please count the teeth on your flywheel 1st thing to double check.( do not take someones word)
crossing fingers for u
brian
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Bjuice..
"I'M YOUR HUCKLEBERRY ! "