Originally Posted by janellemay67
I am not familiar with generators so need a little advice. We have an Onan 4000 Genset emerald plus. It cranks but wont start. Any suggestions please?
First, verify you have well over a 1/4 tank of fuel.
With compression, spark and fuel, it should at least make an effort to light off. The easiest methods to narrow down are as follows;
Spray a little starter fluid in the intake track and see if it attempts to fire off...
...Yes? More than likely a fuel delivery problem, either gummed up/dirty carb, bad fuel pump, fuel filter and/or vac leak...
...No? Check for spark with an ignition tester or remove and ground the sparkplug while another momentarily cranks the starter over visually inspecting the plug gap for a bright blue arc. (KEEP AWAY from the sparkplug hole/flammables!)
No spark? Try another plug...no spark? Ignition problem. Further diag req'd.
Good spark and still No start with starter fluid? Check compression and/or leakdown test.
If fuel and air enter in the ballpark of the right ratio and you got sufficient squeeze (compression), old sparky should light her off assuming nothing else is major off.