smoke but no fire


Active member
Hi guys, long time no see.

Got a problem with a kubota 3 cyl engine in a digger.
It spins over, chuffs out black smoke but wont fire. Occasionally it coughs but it wont stay running if you let off the starter.

The injectors had a bit of carbon on the tips, but seem to get a good fuel flow. Took all the air cleaner off, so no restriction there. Valves all go up and down.
When i spin it over there is some smoke from the breather.

Im thinking head gasket maybe?
Its not a simple job to change as its so tight under the bonnet of this digger (and its stuck in a really difficult place!)

Any thoughts are appreciated!


Active member
The fuel stsytem has been cleaned / replaced as necessary.
As in my previous post, there does seem to be a good flow of fuel from the injectors.
It wont even fire with a squirt of wd40 in the inlet.

What has me is the smoke from the rocker cover. Seems that the smoke from the combustion chamber must be leaking into the galley where the push rods go?


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... its stuck in a really difficult place!
Assuming no broken parts - iIf you can apply enough voltage to the starter, it will spin fast enough to start and you can get it on a trailer. Be sure to remove the connections between the battery and the electrical system (to protect the charging system, instruments, etc) then use two batteries in series connected only to the starter. This sounds like it would cook the starter, but I've owned cars that were converted to 12 volts except for the original 6 volt starter, and that worked for many years. Instant starting!

I've read that WD40's formula changed a few years go in response to the glue-sniffing fad, and the present version doesn't have the volatiles that help starting. Do you have an old rusty can?


I read a while back about soaking a rag in gasoline, then putting it in the inlet by the air filter. Sure helped start my MF165 after I forgot to turn on then fuel & ran out the injection pump.