Yanmar S4D106-FA in Komatsu Wb93r tlb

[Strikebonnie]

I have the above mentioned 74 kw engine in my TLB , assembled in Italy. My machine has always been very difficult to start even in warm weather. Any advice appreciated.

 

[Gjamtrac]

S4D106-FA is Komatsu's model no. for the engine.
Yanmar's model No. is 4TNE106D. This might help you find more info about it.
How many hours on your TLB? Did it used to start easily?
It may need the intake and exhaust valves adjusted. Most Yanmar engines should have .008" clearance when cold.
Improper valve clearance can make them hard starting.
Does your TLB have a Thermostart system for heating the air and fuel before starting? It is usually activated by turning the ignition key counter clockwise and holding it there for 20-25 seconds. Also, pulling the decompression lever/cable for about three seconds while cranking, after heating, may help.

 

[Strikebonnie]

Thank you for the information, will check it out. It does have the preheating thermostat which is operated by turning key anti clockwise . I'm not sure about the decompression lever. (Similar to a motorcycle decompression lever?)I may have to check the valve clearance

 

[California]

Thank you for the information, will check it out. It does have the preheating thermostat which is operated by turning key anti clockwise . I'm not sure about the decompression lever. (Similar to a motorcycle decompression lever?)I may have to check the valve clearance

Verify the Thermostart actually warms the manifold. And verify there is diesel coming down a tube to it. You should feel warmth if you touch it. After some 10 seconds heating, the tiny dribble of diesel should burst into flame. You might hear this and you can see it if the air cleaner enclosure is removable.

Like a spark plug, the TS a component that needs replacement after a while. I just bought one on Ebay, under $10 shipped, cheapest I've ever seen. The TS module isn't unique to Yanmar, MF and likely others used it.

Decompression lever. Yes, same as a motorcycle. Begin cranking with compression released then when it reaches maximum rpm after a couple of revolutions, drop the lever and let the inertia of the spinning flywheel assist the starter. Keep the starter engaged until it will run on its own.

 

[Strikebonnie]

Thank you for this, I will take some pictures and post tomorrow. Just to confirm that it is the same. I can't seem to find the decompression lever/cable actuator.

 

[Strikebonnie]

My Yanmar engine in Komatsu tlb. I have removed air filter to get to injectors to bleed off the air. Still battling to start. Last photo of air-intake after pre-heater activated

 

[Gjamtrac]

How do you shut down the engine (if you get it running)?
Most Yanmars shut down either by pulling the throttle lever all the way back, or by pulling a cable that goes to the injector pump. Perhaps your linkage/cable is not releasing from the shut down position when you try to start.
Try spraying the injector pump area with a penetrant/lubricant such as Liquid Wrench or even with WD-40. Especially on the lever on the pump where the throttle linkage connects.
From your picture I'd say your Thermostart is working!!!

 

[Strikebonnie]

Thank you, normal shut is with cable to injector pump. Will check that out as it looks a bit tacky there. Will update tomorrow

 

[California]

You mentioned opening injector lines to bleed air. According to an old-time dealer who used to post here, that is never needed because air in the high pressure lines will be expelled through the injectors.

Instead, he advised the following for farm tractors. You might need to adapt this a little for your application.

Top of the fuel filter has two bleed screws. Bleed the screw nearest the fuel tank first. Then close it and bleed the second, downstream screw until no air comes out and the filter bowl is filled.

Then go down to the injector-pump inlet and bleed the screw there.

That's all. It's always worked for me after replacing the filter element, or running out of fuel.

 

[Strikebonnie]

Hi chaps just some feedback, I finally managed to get my machine started. It last worked about 8 months ago. Followed the fuel from the tank all the way to the injectors and still wouldn't fire up. You'll probably think I'm crazy but eventually started it with 2 seconds of 24volts. Thereafter it starts fine now with 12 volt battery. So it seems my starter was dragging and not spinning the motor fast enough