I have a Scott's mower with this engine. I bought it not running like this. Upon getting a look at it today, it cranks, will not start and occasionally backfires through the intake. I tried starting fluid with no difference. I put a compression tester on it and it has compression. The gauge is not accurate so I don't know how much. So I took the valve cover off and the valves appear to be actuating normally. Is there an ignition issue with these that I can possibly check or do I need to keep looking into the engine. I have more testing equipment but its an hour away.