Will it pull over fine with the pull cord? How old is the battery? Does it read below 12.5 volts? Do a load test and replace if it fails.
However, the grinding noise concerns me!! I would suggest that you drain the oil and check for metal flakes. If it has an oil filter take it off and cut it open to look for metal debris. If metal debris is evident in oil/filter there’s something serious going on and further investigation is warranted. If nothing obvious replace the oil.
Remove the spark plugs and see if it cranks over. Possibly the compression release is faulty?
Keep us updated 🤞

 

The engine is basically “locked up”. But, it will turn/rotate almost one full rotation in either direction; then abruptly stops.

I would pull the valve cover and observe the operation of the valves as the engine is turned.

 

Pull it through without the spark plug in. If it moves easily around a revolution, suspect the automatic compression release. If there is no change pull the valve cover and check what the valves are doing.

 

Thanks to all three of the replies above. In reply:
It will not pull/turn any differently with the pull cord or otherwise.
The battery is fully charged and strong.
It is the same with or without the spark plug in place.
This feels like a mechanical lock up. It is a very solid stop and does not seem like a compression or liquid-lock. I intend to “open it up” soon and inspect the valve movement, any possible issues with flywheel/magnito, etc., as well as check the oil for metal. Currently, I have another more pressing issue to contend with but will posts updates here as I get to it (Hopefully by tomorrow 🤞)
Thank you all for the input and suggestions.

 

Yep, sounds more like a mechanical issue unfortunately. Maybe a pushrod has dislodged, or a valve guide has shifted into the combustion chamber….. 🤷
Let us know what you find

 

I can easily rotate the engine shaft, but only almost one full turn. When manually turned it will easily rotate in either direction but stops — hard — at the same point of rotation each time.

My first thought would be that the connecting rod/big end may have corroded seized in your absence and 'disconnected' itself from the crank. That would allow you to rotate in each direction until the crank throw made contact with the rod...probably almost one full turn. You can quickly verify this by removing the spark plug, placing basically anything in the hole, like a pencil, etc. and seeing if turning the crank makes the piece go up/down. If it doesn't move, there's no longer any connection between the crank and the rod/piston. Hope not, but bent push rods would keep the valves closed, not open them further, and this is very unlikely to be an interference engine where the piston could make contact with the valves if the timing gear broke. Nevertheless, valve interference would produce the same effect.

 

i bet it is a dropped valve with a keeper missing.
there has been a few as of late that the keepers have failed.
pull the valve cover and look. close.
a valve might be stuck as well.
pull the spark plugs and check rotation.

you might get lucky with new valves and keepers.

 

🤞. I’m thinking along these lines too. Hoping that’s the extent of damage.
A big THANKS to all the replies and the additional information. (I too am curious about those “durability hours“. I’ve got double that 250.
i have been working on another very pressing issue, and still not completed. But I hope to take this generator back home in a couple of days and check it out thoroughly.

 

Do you know the actual maker of the engine? My guess is the 457cc Ducar. I have the same engine on my Pulsar PG12000B dual fuel. Will be very interested in your findings.

 

I do know the 713cc as used in WGen12000 & DF is a Ducar.

 

Looked up the spec sheet and it shows the engine is a Westinghouse 457cc but I bet it is a Ducar. Almost all the Asian (not Honda) manufactured units have Ducar engines.

 

Look for an emissions sticker on the unit. The manufacturer should be on there. If not, you can look up the engine Family Name and get the manufacturer. Mine is a Rato engine.

 

Not to sidetrack the discussion but what does the "Durability Hours 250" actually mean?

 

Apparently it is a measurement of how well the emissions from a particular engine hold up with use (hours). I got a lot of hits when searching for this information, but no direct answer.

There is a graph in this PDF on page 24 that shows an example of the Deterioration Factor (Emissions vs Hours), but that isn't really a definition of "Durability Hours".

 

did ya leave the gas turned on after last use ? I've seen motors get hydro locked cause the gas filled up the cylinder .
animal

 

I finally had a chance to do a little checking into the generator problem last night. So: regardless of spark plug in or out, the crankshaft will rotate only about 330 to 345 degrees. Simply won’t make a full rotation in either direction. The piston IS going up and down without any apparent issues. Both valves are operating normally without any (apparent) problems — neither valve stuck or loose; and pushrods are straight. Flywheel and magneto are free of impediment. Oil is clean, free of metallic debris. I don’t have a camera scope to examine closely, but I don’t see any evidence of other obtrusion (I.e., excess carbon buildup, etc.) in the top of the cylinder that would be preventing the crankshaft from revolving.
I hope to be able to work on it again tonight and am thinking about trying to “separate“ the engine drive and generator to isolate the two. Perhaps the lockup problem is in the generator? Does anyone know if there is a simple “disconnect”/disengage between engine and generator? Has anyone heard of, or experienced, a n actual generator lockup?

 

Here’s the engine info:

 

Here’s the engine info:

New Vehicle and Engine Certification: Executive Orders for MY2021 Small Spark-Ignited Engines - Exhaust | California Air Resources Board

The New Vehicle and Engine Certification Program is responsible for the certification of new engines, vehicles, powertrains, aerodynamic devices and other new certifications. Vehicles and engines may be sold and otherwise produced in California only if approved by Executive Order (EO) after...

ww2.arb.ca.gov

 

FYI, Dajiang is also registered as Ducar.

DUCAR-Vertical Engines_Horizontal,Engines

DUCAR is committed to the design, manufacturing, and service of power generation equipment, cleaning equipment, and garden intelligent terminal products.

en.ducar.cc

 

I wonder if you could get one of those flexible scopes up into the oil drain hole to see if the rod cap bolts worked loose or something. I would have expected metal debris in this as well.

I did have a friend with a Briggs generator that seemed to have a defect in the timing set. The timing gears were not integral to the cam or crank and mounted using a keyway much like you see on a flywheel. The keyway was right in the valley between the teeth so had the least amount of metal and strength. It broke once, bent the pushrods and rocker arms. He replaced himself the first time around, figuring it was a fluke. Then it happened again about about the same number of hours and he gave up on the unit. I wonder if something like this happened but would expect metal debris.

I was given a non-running generator that had some similar engine issue. It had spark and would rotate but just pop and sputter. I decided to just scrap it instead of trying to make it work as it looked like the cost to fix would have exceeded that of a newer and better model.

Conor

 

Here is an exploded view of the 457cc Ducar on my Pulsar generator. Might be the same motor. Maybe it will help. I still think something is broke or failed in the interior of the motor. Since the motor will only make a partial turn something could still be wrong with the camshaft and valves. With no more rotations of the motor you are not able to verify the full functions of the camshaft and valves.

 

remove the pull rope cover assy to expose the flywheel
make sure everything is free from parts as the fly wheel magnets like to pick up a loose bolt.

remove the spark plug
and the valve cover
loosen the rocker arms to back off the action to the valves 100% or remove the rocker arms and the push rod.

measure the distance or valve stem length to make sure the valve is closed and seated and not hanging up as in a bent valve

then see if the engine will rotate by hand

 

I had an engine that broke a tooth/teeth off the fiber camshaft drive gear. Its symptom was valve timing changing unpredictably although the valves still opened and closed (just not at the right time). I could see where this problem could also result in stopping rotation at the same specific spot.

 

Was that a Kohler? I had this happen with a riding mower that used a nylon timing set. Kohler makes a good engine but not the consumer grade stuff. I suspect that an engine in the generator I junked has something up with the valves or timing set as well but the valves still opened. That was an older Tecumseh L-head (not my favorite) and decided the entire thing wasn't worth messing with.

Conor

 

@ SteveT and Iowagold, I have done “most of that”, but will go ahead and take the rocker arms off and recheck. The valve rockers are both very loose, free from spring tension, at/near the TDC of piston travel (as should be expected, so valve timing must be at least kind of close to correct), so doubting the valves are protruding into the combustion chamber and thus causing the block/lockup; but will give that a try anyway. I will also try to get a look at the rod bolts to see if perhaps one has backed out… BUT, the point of rotation where the lock occurs is at a point when the piston is nearly at the top of cylinder. I’m thinking logic would suggest that a protruding rod bolt would more likely interfere with crankshaft rotation at or near the bottom of stroke, not the top. Again, it still may help give more insight into this problem to take a look.
Does anyone know how to disconnect the engine from the generator drive? That is, without having to go through the entire process of removing one or both. Is it just wishful dreaming to hope that it is as simple as a set-bolt or sheer pin?

 

so what is the exact valve lash?
have you backed off the adjusters yet?
if not then do that and see if that helps.
and what is the valve stem height for each valve?
that helps to see if there is an issue with the valve closing
bent valve or trash in the valve seat like a bolt or other hardware wedged on the valve to the valve seat. or even a valve seat that came loose and is partial wedged in there leaving the valve partial open for zero clearance.

so you are still with the spark plug removed right?
yea look for something on top of the piston or dents in the top of the piston with a bore scope
if you are at less than 360 deg rotation

from there you are in the bottom end of the engine
there was another video on youtube where the dip stick plastic broke off and got in to the internal cam gear and locked it up.
just throwing that out there.

also look at the starter assy and the flywheel area
remove the pull rope cover look for trash if you are at less than 360 deg rotation.

question how many deg of rotation are you getting?
is it over 360 deg?
if so then it is related to the cam gear.

remember:
4 cycle engines are 720 deg rotation for a full cycle
or two times on the rotation of the flywheel.

 

It is not simple. The crank shaft output end of the engine is tapered and the generator mates to it without a key or threaded connection. It is simply a tight friction fit. YouTube has some videos showing the removal of a generator head from an engine. Basically you start at the generator end and disassemble the generator piece by piece. You will probably have to use some type of puller to do the actual separation of the tapered fitting.

 

There's a James Condon youtube video separating the crankshaft from the genny rotor. He used water inside the rotor shaft and threaded a bolt into the rotor shaft with teflon tape to help seal. Crank the bolt down and water press pushes them apart.

Here ya go:

 

Can you feel any compression? Is piston moving up and down? Can pull plug and insert a plastic straw or similar to "feel" for movement.

 

If it's happening as the piston is nearing TDC sounds like some foreign object is in the combustion chamber to me if your saying both valves are closed. Unless it's something to do with a compression release issue if it has one. Most times it's usually something simple.

 

Unless it's something to do with a compression release issue if it has one.

Exploded parts diagram shows a compression release.

 

May be time to pop the head off. That would at least eliminate/show piston clearance issues.