Next generation ucm1-3.5 generator will not start

[Sulaire]

Title of the thread says it all!!

This 1 cylinder diesel generator has always been difficult to start, but now it will crank away but not fire.

Changed the glow plug and tested it , checked oil , water air , bled fuel at the injector, tried turning fly wheel by hand and there is resistance at one point but I can push through it. Batteries are full.

The solenoid pulls in on cranking, so really I am at a loss!

A friend suggested easy start fluid (ether), but I am not too sure about that!

It only has 98 hours on the clock and is 5 years old

Any suggestions?

Charlie.

[skipmac]

To crank a diesel needs compression, fuel and oxygen. Of course getting them all to happen at the right time helps.

Not sure if you should be able to turn over the diesel by hand but assuming that's OK then you have compression and air so must be fuel.

If you have fuel at the line connecting to the injector then my guess would be an injector pump or the injector. If you crack the line leading into the injector and crank the engine do you get a nice spurt of fuel out of the line?

[skipmac]

By the way, be careful using ether on a engine with glow plugs. Never tried it but have heard that this could go boom!

[Sulaire]

Hi skipmac,

Yes when i crack the injector nut I get pulses of diesel until I crank the nut closed again.

Thanks for the warning on ether , I was a bit sceptical too , but it sounded a nice easy fix! I shall resist temptation for the moment!

Charlie.

[btrayfors]

Bad fuel? I have the same 3.5KW NextGen in a sound enclosure. Never had starting problems, but a few years back I got a load of bad fuel which caused the generator to only put out about half it's usual power before stalling.

Relatively simple way to test would be to get a small day tank and feed fresh diesel fuel from that tank to the engine.

Bill

[capngeo]

I've had issues where cylinder glazing from running a lightly load Diesel, causing low compression.. Low enough that cold starts were impossible

[witzgall]

DONT USE ETHER!!!! If you want to try and help it along with a cold start, try a hair drier into the air intake.

Chris

[LaBomba]

Sounds like you have fuel, it is rare to get bad fuel. Air is usually a given, take it you have cleaned or changed the air filter?? That leaves compression and like previous posts I wouldn't expect you should be able to turn this over by hand. You don't by any chance have a decompression lever on this engine do you? They are used on many diesels to get them turning over then the decompression lever is moved to the run position and the engine will build compression and fire up. Look for a small lever on or near the valve cover. Just a thought. Good luck!

[Sulaire]

Well, i have exhausted all avenues, injectors are fine and firing fuel, air filters cleaned, even tried a little motor start fluid spray, but no luck.

Tomorrow I will take the head off and hope it is something simple like a stuck valve as compression is the only thing left that can be wrong , not doing a compression test as I can only assume this is the problem......

Fingers crossed.

[Charlie]

I am finishing up a rebuild of the kubota engine in the same generator. Turns out that it was a compression problem. Somehow water had got into the cylinder and caused rust. Also the water had rusted one of the valves. I ended up having to replace one valve and had to take the head in and have the seat reground. I tried to lap it but the pitting was too deep. Because the engine is horizontal any water accumulates in the valve and the cylinder causing problems. PM me and I can get you more info. The guys at Nextgen are very helpful as well. Before you tear the engine down make sure that the decompression lever on the valve cover is in the correct spot.

[Sulaire]

Hi charlie,

Pm sent , thank you

Charlie.!

[Sulaire]

Success! , it turned out to be an easy fix in the end thankfully!

There was no gap between one of the vavles and tappit , so the valve was slightly open so no compression!!

We set it to factory setting and gen started first time, for the first time EVER!!!

Thanks to everyone who replied

Charlie.