Picked up an Ariens 624 today. Pulls over real easy. Like no compression. Has the OHV 6 HP Tecumseh. I am not real smart when it comes to OHV. Is it like the older engines where the exhaust valve wouldnt seat all the way and have no compression? Any advice on where to start would help. Has the dual pulleys on it. I have an older 6 and a 4 with double pulleys if I have to repower?