I just purchased this and I took the carb off, shot starting fluid into the head and it started to run. I ordered a new carb put it on, it will not fire and backfires thru the carb. It seems to have plenty of thru the plug. will not start. It seems to be getting fuel as well. Any ideas, I would love to hear them, Thanks

 

If you have spark,check the valve clearance. From what I've found online,Ex: 0.0071~0.0091, Int: 0.0059~0.0079" Plus if it's another one of those Chinese knock off carbs,check the bowl for trash,blow out all openings and check that the jets are the same as in the oem carb.

 

Also check to see if spark is hot enough.. leave a 3/16 gap between wire and plug and see if you have a good blue spark! Yellow spark means weak spark. You might check cimpression also.

 

Its running but not without battery power. I checked the stator 7 volts all around (3 phase) and I checked the rectifier out of circuit, appears to be good, not sure about voltage regulator, checked white wire to ground with 13.94 volts, note this was connected to the battery. disconnect the wires from the battery, it dies immediately. Ideas please. Thanks

 

Has to have the battery for the ignition I do believe on this one. It's not like the old magneto triggered systems like Polaris used for a long time where the battery was there for the starter,lights,fan,etc. If you're reading close to 14 volts at the battery while at an idle or above,then the regulator should be ok.Best way on this an all machines is to have a good service manual.

 

Yes the 300KLFs are car style DC ignition, so need battery power to run. Check compression, I agree with OPT about checking valve clearances, though where he gets those "tenths of a thou" feeler gauges from I don't know. If the valves are OK and you have low compression, time to take the head off and find out why. If compression is OK you probably have a faulty new carb.

 

So this system charges the battery then uses battery power to operate. If this is the case, sounds like I should check out the battery. Will this system stay charged with a good battery? Thanks, Ted

 

Whats a service manual?

 

The voltage regulator as it's running keeps the battery charged. You should have between 13.5-14.5 volts on average at the battery while at an idle or slightly above if the regulator is ok. IF a battery has a bad or weak cell it may not be able to hold a charge. Any auto shop can load test a battery for you. If it fails the load test,get a new one.

 

This is a service manual.. Look at the charging section and you can learn a lot..https://www.tradebit.com/filedetail....service-repair