i have a 1972 model merc 500 or a 50 hp and the only thing wrong with it is the previous owner sprayed starting fluid into the top carb and fried the rings in the top 2 cylinders we did a compression check and the #1 cylinder only had 30 pounds of compression and the #2 cylinder had 90 the #3+#4 cylinders both had 125 so if there are any prices on this problem and the price on parts and labor any prices at all will be help thanks for looking nick 
