Posted by Caleb in Manhattan KS [70.184.232.53] on Thursday, May 22, 2014 at 13:48:59 :
I've been racking my brain over the running condition of the WC. Tried everything I could think of...New cap and rotor, KNOW good distributor (2 of them, one had been running just 2 days before), Timing great, not sucking air, 3 different carbs, and the list goes on... Anyway, thing ran like crap through the parade on the 9th so I got home, ordered a fuel pressure regulator so i could throw the original Holly back on, and an accel pedal since my hack job was a bit too unpredictable, then took a week off from even looking at it. I threw the new regulator and old carb back on, set up the accel pedal, and took it for a short drive down to the folks to work on the injection pump on the D17 and at first it was running MUCH MUCH better, then I pulled out of the garage to head down and it started popping again. Dad was listening to it and thought maybe the exhaust was too big and there wasnt enough back pressure (his Harley has that problem and it was fixed with baffled tubes). Long story short, I fixed the leaky IP on the tractor and went home. As it just so happens, I was underneath thinking over the exhaust I heard a rattle so I went to the end of the pipes and found a loose hanger bolt, when I reached up to tighten it, I noticed that the pulse felt funny....put my fingers over the tailpipe and could feel a definite suction between pulses......have the head gasket set, pulling the heads to find a (some) burned valves this weekend. Luckily, I have a set of big valve heads and a different cam laying around if it ends up being too bad.
Never would have thought a motor that had been somewhat recently rebuilt (including a valve job) would burn a valve...but I have the signs. Guess it's a case of "Forest through the Trees".
Follow Ups: