Join Date: Dec 2014
Location: Eastern most Iowa
I am thinking :Vapor Lock: If it was rebuilt 40plus hours ago, no problems until lately, that cancels out the valve lash. But, if a fuel line was redirected to a "hotspot", that would cause the fuel to vaporize after the regulator and before the fuel injectors, wammo! Instant vapor lock! Hard start, backfire... YEP! Baja boats had this problem with the fuel injected 502's, Ran great while the cold fuel was pouring in, but when it got hot, after slowing down, did exactly this. I know I'm comparing 2 different beasts, but... That's exactly what the Baja's would do. Next time it does it, CAREFULLY... Very CAREFULLY, let the pressure off the fuel line. Once its expelled, tighten it back up and try it. We used tire valve removing Tee's to loosen the Schrader valves, on the fuel pressure regulator. I'm sure the A/C is different, but it may be the same concept. Once the pressure was relieved, the 502's would fire right up.
If it fires right up and runs good after doing this, look for a place where the fuel line could be getting hot and insulate or re-route it.
Might be a long shot, but if I were a gambling man...
Oh, ya.... I am!
'09 650XT H1, 72" Eagle Plow, Warn 3500 Winch. Bestop soft cab, soft top, wind buster & cargo cover. Dyna FX CDI box, UNI filters, A/C V-bag and front console, EPI 2" lift kit, Highlifter springs, Scat ProCar suspension seats with heated covers. SteerLite bushings. 28x10 Raceline Bruisers on Vision 158 14X8 rims, on all 4 corners. Cowling heat vents w/fan. Factory heat and defrost. RD Custom's alternator kit. XTZ hood scoop, Monster shock covers, turn signals... for now.