Hi people, my father has a 10.5hp briggs engine in his ride on mower. When you first start it it runs fine, but after it has a chance to get hot it begins to run rough. The revs drop and it pops and backfires etc. You can stop mowing and just let the engine run and it MAY return to normal and you can continue to mow, Then 5, 15, or 30 minutes later it'll do it again. There doesnt seem to be any rhyme or reason to it, it just plays up whenever it feels like it. Initially i thought if may have been a fuel blockage but ive been right through the fuel system and its clean. Then we thought it may be the coil breaking down when hot, so we replaced the coil, but unfortunately the problem is still there. If anyone has any ideas of where to look next i'd be grateful for any suggestions.
Thanks.
