ok so im going through all the ipls I have (1988,1988.2,1991,1993,1998 and 2000)
clutch 501 67 52-02 is up to 1988. It is the old type with one long continuious clutch spring right around the 3 clutch weights. Rim drum is 501 59 77-02 and oiler is small drive gear, V ring and plastic seal type
clutch 503 47 19-01 starts in 1991 and changes in 1998, is the newer 3 individual small spring type. Rim drum is 501 59 77-02 and oiler is small drive gear, V ring and plastic seal in 1991. In 1993 the oiler and drum change to the newer large, flanged, oil drive gear and drum 503 62 59-01
clutch 503 70 15-01 same 3 small spring type, 1998 to current? large, flanged oil drive gear and rim drum 503 62 59-03
Crank part # does not change through out.
NOTE: in my original post I noted that "503 47 18-01 up to serial number 4250001" THIS IS NOT THE CLUTCH, BUT THE CLUTCH SPRINGS!
There is also another note showing a change in the large, flanged plastic oil gear drive and the metal oil pump drive on pump shaft. "Up to 3350001" It also shows rim drum to suit which is 501 59 77-03. This tells me, within the newer oiler, there was a change to the 2 drive gears and hence a change in rim drum.....This doesnt make sense as the very first large flanged oil drive gear is the same part number from as soon as it first appears to 2000. Only showing the change in the last 2000 ipl??
Now the drum I have is just a oregon drum part # 28094. So I dont have the husky part number on it. I have no idea if there is any physical changes in the "husky" rim drums either clutch side or rim/oil pump side?