Hi All,
New to this forum, but have been searching and lurking trying to figure out this issue with new 587 short block just installed in the SP.
Basically, got everything installed and it idles well, but backfires when you try to give it gas both out of exhaust (bit of flame noticed at one point) and pops out of the carb too. I had checked the exhaust for restriction (none). SBT Tech recommended new valve and valve cover. Installed both and timed per spec; no change.
I turned to focusing on the electrical system as I had put a timing light on it and it seemed to flicked and go dark sporadically at the higher RPMs so figured it was loosing spark. Went down the electrical road, checked voltage (13v) at idle seemed ok, unplugged rectifier anyways didn't change anything. Clipped plugs back, no change. Battery was weak so replaced that; no change. Got a complete ebox off ebay (used) installed that no change. I had also cleaned the flywheel as there were some metal shavings in there from the starter. Thought that may have been shorting the stator/flywheel as there was a couple very slight scratched on the stator. Also replaced stator after that; no change. So only thing lefty on electrical system is flywheel not sure how it could be that. The only other thing I was thinking was maybe the start button is possibly shorting....?
Puzzled at this point and looked other directions. Searched and sawt that backfire could be caused by lean condition to ran off of fuel bottle. That seemed to help it run a bit better but still had a hesitation. Changed plugs at the same time, went back to backfiring, but at least I think I got some clues that maybe its fuel related. So thinking about rechecking the carb to make sure that its pumping correctly and the replacement jet was the right size. Had rebuilt originally and adjusted everything to spec. Pop off was a bit low but hadn't worried about that at the time. Had noticed the high speed screw was out a few turns on rebuild. Its at 0 now.
I guess I am going to look at the on/off/start switch and recheck carb. I am running out of options...? Any ideas? I would appreciate them. Thanks.
Ryan
New to this forum, but have been searching and lurking trying to figure out this issue with new 587 short block just installed in the SP.
Basically, got everything installed and it idles well, but backfires when you try to give it gas both out of exhaust (bit of flame noticed at one point) and pops out of the carb too. I had checked the exhaust for restriction (none). SBT Tech recommended new valve and valve cover. Installed both and timed per spec; no change.
I turned to focusing on the electrical system as I had put a timing light on it and it seemed to flicked and go dark sporadically at the higher RPMs so figured it was loosing spark. Went down the electrical road, checked voltage (13v) at idle seemed ok, unplugged rectifier anyways didn't change anything. Clipped plugs back, no change. Battery was weak so replaced that; no change. Got a complete ebox off ebay (used) installed that no change. I had also cleaned the flywheel as there were some metal shavings in there from the starter. Thought that may have been shorting the stator/flywheel as there was a couple very slight scratched on the stator. Also replaced stator after that; no change. So only thing lefty on electrical system is flywheel not sure how it could be that. The only other thing I was thinking was maybe the start button is possibly shorting....?
Puzzled at this point and looked other directions. Searched and sawt that backfire could be caused by lean condition to ran off of fuel bottle. That seemed to help it run a bit better but still had a hesitation. Changed plugs at the same time, went back to backfiring, but at least I think I got some clues that maybe its fuel related. So thinking about rechecking the carb to make sure that its pumping correctly and the replacement jet was the right size. Had rebuilt originally and adjusted everything to spec. Pop off was a bit low but hadn't worried about that at the time. Had noticed the high speed screw was out a few turns on rebuild. Its at 0 now.
I guess I am going to look at the on/off/start switch and recheck carb. I am running out of options...? Any ideas? I would appreciate them. Thanks.
Ryan
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