Quick history:
Bought it about a month ago and when I test drove it, it ran good. Loaded it up and took it home. Owner said it had been sitting for a long time, but was "just serviced". It only has 500 miles on it total. Drove it around and found out the charging system wasnt working...so had to charge the battery once every week and a half or so. One day my daughter was driving it and it died. I couldnt get it to start again and I noticed there was no fuel in the filter...I first checked pulse/vacuum line to make sure it was sucking and it was. So I replaced the fuel pump with one I found local...which is for a large riding lawn mower...and it worked. Engine started and ran, but struggled at low speed immediately following running it at higher speed. It would bog when decelerating. I have also noticed now that it will backfire some on decell and die.
In the meantime, I went ahead and installed new stator and trigger coil assembly to get the charging system working again (that was an issue because it would not start at all after that...but eventually found that the trigger coil was wired backwards in the plug from the factory). I have also set valves, but I set them to .005 (intake) and .007 (exhaust)...per the manual. But what is weird is the manual states its mainly for the 700 series, but "can" be used on other models. On the front it says 500/600/700. I have noticed that the most common setting seems to be .005.
Anyways it still has the issue to me that seems like its running lean. Not full power now, struggles immediately running it faster, and will die and pop some on deceleration.
My main problem now is that it wont get to higher rpms as fast as it did when I first bought it. It struggles on deceleration after running near top speed.
Things I have done:
changed fuel pump
replaced stator / pickup coil
thoroughly cleaned carb (twice)
set valves to .005 and .007 (is .007 too loose for exhaust?)
anyways it seems to have a lean problem, and wondering if you have any suggestions on what to check.
Thanks
