So, i have a 2003 yamaha kodiak 450 ultramatic, it wont start, it just crank, i am suspecting some electrical issue because i have good fuel, strong spark, compression is at 150 psi. it wont even start on starting fluid, so something tells me that it has something to do with the electric. The battery is only a year old and it seems like it sometime wont crank, it just does the thing where it like if the battery is not charged, even tho it is. So it is almost like something is drawing too much current from the battery. Does anyone has any idea what it could be, because i am at a loss on this one. if anyone has had this issue themselve, how did you fix it. also, if anyone has a good wiring diagram, i would greatly appreciate if you can share it here. thx

 

Check that TDC by the flywheel agrees with actual TDC by checking the piston through the plug hole. Difficult to tell exactly, but if a flywheel slips round, it usually gets far enough off to be obvious. Check the inlet manifold for cracks, Yams are rather prone to them. Clean the carb out, remove float bowl and jets, blow both jets and the holes they came from out, with compressed air, no need for rebuild kits, and no altering needle settings, if it ran OK on those settings before dirt or water got in, it will run right once the dirt/water is out.

Forgot to mention, check earth leads from battery to frame to engine, even if it looks OK the frame earth can corrode.

 

I like to add a spark checker inline with the plug. Great for seeing what is going on.

If it won't backfire or do anything on starting fluid then maybe the spark isn't getting through to the plug. Or the plug is wet and fouled.

Never hurts to leave a battery charger on it to ensure good enough voltage while troubleshooting. Keeps the battery from getting run down.