Hi All,
Maybe not a true blue transport issue, but just last few days, eldest son rang me with some backup generator problems.
Unit in question is an 8 kva powered by a Kohler single cylinder, horizontal crank, ohv engine.
Reported had been running ok, came back from a weekend away, started ok but after about 15 seconds, kept cutting out.
We took the fuel tank off, blew all the fuel lines out up as far as the carby, drained the fuel bowl
which looked clean.
Tried a brand new spark plug, still the same.
Had tried it with the air filter removed and did notice that when it does cut out after 15 odd seconds, get quite a backfire and like the engine is trying to "run on, as in pre ignition".
We run out of daylight, asked a few locals what they thought the
reason may be.
I would be thinking should only be fuel, havent completely removed the carby as yet, son getting a drivers manual tomorrow, OR spark.
One bloke suggested that seeing it is NOT the spark plug,(new one tried) there may be a breakdown in the coil/ magneto side of electrics, but if that was so, surely wouldnt keep starting even if running for short times??
I know very little about small engines, mine either work or they dont,
Anything to suggest??
Thanks, Dave_64

Cogz
m80
wen it cuts out
while it is still spinnin
see if a wiff of Aerostart will keep it go n
if so .....may B fuel problem
cya

.Make sure the fuel tank breather hole is not blocked...............
...........( Loosen the fuel cap a bit and see how it goes )...........
.................Billy...............

These problems can be fun to solve. I think since you have gone most of the way along the fuel system continue and strip the carby and look for any crap even if there was nothing back up the line.
Then its time to start testing the electrics especially the HT lead for continuity from coil to the connector on the lead. These may have an electronic module and I have no idea on how to test them. So before digging into the electrics with the plug out connect it to the plug and earth the plug and turn it over looking for spark. If you have good spark back to the fuel. Depending on the age of the engine and type of electrics it would be strange for the timing to be out so again look at the fuel.
Is there a remote chance that a fuel line has a flap inside due to age and is blocking the fuel?

Maybe try any other spark plug that fits, a new plug is not necessarily a good plug, i have come across faulty new plugs in the past. It's not likely, but the possibility is often overlooked when fault finding.

Is it a gravity feed fuel tank or uses diaphragm pump??

Dave, this probably won't help You (or Your Son). But I've got a combined Welder/generator powered by a 13Hp Honda Motor. The Honda has an Oil Alert Feature.!
There's a Low pressure Oil Sender in the Sump wired into the Ignition circuit. When the oil pressure Drops It Shuts Down. It was behaving exactly as you Describe.. Turned out the Oils pressure sender/Switch was Faulty.
We bypassed the Sender about 10Yrs ago & It Still starts First Pull..

Another crazy thought is a faulty cut out switch.

Reported had been running ok, came back from a weekend away, started ok but after about 15 seconds, kept cutting out.
We took the fuel tank off, blew all the fuel lines out up as far as the carby, drained the fuel bowl

Most have a filter in the fuel cock. Probably dirty.

The oil level switch fail too; as per Hayseed's comment. The float part binds and locks off. I have spares if you need one. (Chinese clones).

Also, if the fuel line hasn't been replaced, do it as a matter of course; they fatigue and fall apart. Fit good quality Gates or something brand. Not the single wall Chinese rubber stuff.

The fuel fill the bowl and if drawn up the centre (emulsion tube and main jet). Very easy to unscrew and clean. There is also a breather hole in the aluminum
casting near where the float bowl mates.

And, check if the kill solinoid on the bottom of the flat bowl is not jamming/blocking the emulsion tube. (also have a 13hp genny chinese clone carbies if needed.)

Gents!
Thanks for all the input, son has downloaded a Kohler manual, I havent had a look at it yet, did pass on a cupla simple tests he can do himself, like having a spray bottle with a bit of petrol in it to try and distinguish between fuel and spark, check breather in cap not blocked( its not).
Waiting to see whether he's blown himself up or not!
He lives about 20kms north of me, probably have to go out and bring the genny here to work on it.
Dave