seems to me that the engine has to have some provision for thrust on the crankshaft, so that you could maintain end play to some spec called for

Mike makes a good point with checking the con rod for play, it should have some end play, where you can moved it back and forth on the crank journal, easy enough to check while you have the side cover off the engine.

anyone got a drawing of the innards of this engine model?

bob g

With recording tape, it's called "stiction".    In an engine, I'd look for oil that turned to grease.  Odd, because once you got it moving, should be able to set an hour and still be free.  Can you feel any play in the connecting rod ( upper or lower ) ?

something in the piston area seems to be the only large enough surface contact to "stick". 

Maybe Felts on the bearings ?

https://en.wikipedia.org/wiki/Stiction

Having worked as a genset tester at the Cinderford works of R A Lister during the first five months of 1969, I recently bought an SR2  6kW Startomatic produced in that year which I may have just worked on in the factory. (From 1971 to 1980 I worked in the Overseas Operations Division of RAL, including setting up and running Lister Diesels Malaysia, where some 10,000 engines were assembled from CKD).
It was bought unseen during the lockdown, and turned out to be incredibly filthy as a result of over-fueling - instead of SR injection pumps, ST had been fitted, which caused No.1 inlet valve to become badly worn/burnt. Fuel rich exhaust shuttled back and forth through the inlet manifold and the oil bath air cleaner to No.2 cylinder, and with no crankcase depression, oils leaked everywhere.
Cleaned up and with new valves and seats, de-glazed bores, a set of piston rings and big ends, and serviced fuel equipment, the engine runs very nicely. After cleaning and some rewiring, all of the Startomatic functions operate correctly, except that the decompressor does not actuate on account of insufficient AC voltage output (only 30 volts) from the Brush alternator.
Tests proved that there was a major short on the AC windings of the armature. Estimates from trade professionals for rewinding are in the region of £1,000.

Does any one know of a Brush SCTF 2.25 armature or complete alternator available for sale?. I am in Monmouth, South Wales (UK).
LDM

Been thinking, with the drive pulleys set up to operate the engine at 3000 RPM’s the Kubota engine should pull a 3500 watt load.

On my EB300 engine, the rating is 6hp at 2600 RPM. It will put out 2500 watt continuous and 3000 watt intermittent. How long? I don’t know. It’s in hours. The surge capability is very good. It just handled over a 50 amp momentarily surge last week. The generator has no problem starting a 1.5kw nail gun compressor with the air tank having 120 psi pressure during startup. The engine handled it easily.

Your EA330 should exceed the EB300 rating with ease. My guess is it should handle a 3000 watt continuous load with a proper cooling system. And a 3500 watt load intermittent for an hour or more at a time.

The EA300 & EA330 Kubota engines put out almost the same hp. and torque. It’s so close that it makes no difference which one a person has.

Over ten years ago while I was talking to a Kubota application engineer and I ask, why Kubota increased the bore on the EA330?  His answer was, to help the engine meet new tier emission standards.

They also got rid of the jet start device that aides startup in extreme cold weather. My guess is when the device is used on startup and once the engine fires up there will be a white cloud lingering in the air until the extra fuel that was injected in the intake is used up. It’s too bad the jet start device was removed because that extra fuel definitely made a difference in cold weather. Especially if you had a dead battery and the glow plug was inoperable. I’ve used the jet start regularly on the EB300 build and the engine usually fired up the first or second try.

In my opinion, the Kubota EA, EB and EL series engines are great little engines.


(Corrected typos)

 thanks for the reply..
 
 It's prybar stiff cold or hot, no difference. Once it starts to move there is not much resistance. My plan is to take the head off and start from there, I guess just keep dissembling until there is a noticeable change in resistance.

Dave..