The Classic Machinery Network

Hello all,
I hope someone can help me.
My Yanmar yb301 slipped into a trench while I was working, it ended up at 45 degrees and I tried to get myself out by using the bucket, the engine made a nasty grinding noise so I turned it off and had to get someone to pull me out.
Once out I left it for half and hour and then started it up and used it with no apparent problem for approximately 40 minutes, it slowly died on me and would not start, it would turn over showing exhaust fumes but would not run.
I assumed I had blocked the fuel pump, I sent the pump away for a rebuild and replaced both fuel filters as a matter of course.
I have now fitted the pump back on but it will not even fire, I have tried the injectors outside the cylinder block and they all fire fuel perfectly.
The compression seems fine as well
I have taken the end cover off and made sure that all the letters align properly, A-A B-B and C-C, the confusing thing is that with all the letters aligned the timing marks on the pulley show that it is 90 degrees out, I cannot see how that could be but it is.
Is it possible for the fuel pump to be out 120 degrees ? I have even tried easy start in the air intake and it still will not fire, I have no smoke from the exhaust at all.
I have a parts manual but have been unable to get a workshop manual to help me.
I do not want to end up scrapping the machine as I know its old but it does every thing I need it to do around the farm.
Can any one point me in the right direction please.
Engine number is 3TN84L-RB

Hi Andy seeing what you have posted my first guess would be that because the machine slipped into a trench at an awkward angle there may very well have been oil starvation causing some internal damage to the engine? Unless the engine was physically damaged I cannot see how the timing could move out.
The only other possible problem could be that if there was any muck in the diesel tank the awkward angle of the machine could have caused it to be sucked through the system; my only suggestion would be to try and start the engine from a gravity feed thus bypassing the filters (even though you have changed them) if the engine will run through a feed of clean fuel through gravity then you may have found the issue, if not you may be facing a bigger problem.
let us know how you get on.

Jeremy

Hi Jeremy
I have spoken to a mechanic friend of mine and he said that I should be getting either smoke or fuel fumes out of the exhaust, I am not getting anything but I do get fuel from the injectors when I have them outside of the engine, more worryingly is no firing even with the easy start.

luciousesox wrote:Hi Jeremy
I have spoken to a mechanic friend of mine and he said that I should be getting either smoke or fuel fumes out of the exhaust, I am not getting anything but I do get fuel from the injectors when I have them outside of the engine, more worryingly is no firing even with the easy start.

Andy I have recently seen a little Peljob excavator where the engine would not fire; she would crack a bit with easy start but still not fire, in the end the chap who owns it spoke to a lad who used to work on them and he reckoned the bores and pistons were worn so the lack of compression was causing the issue, this turned out to be correct.
I do wonder if a similar problem has occurred with your engine as it has been run at an awkward angle? Sadly I cannot offer you anymore advice but I cannot see how the timing could slip, is it belt drive, gears or a chain?

Jeremy

a engine needs few things to run fuel. air. and an ignition source
how have you checked compression as you need to use a compression tester try doing all cylinders and take a reading

then put oil down boars try again
also when pump was rebuilt don't assume that it was done right I have had every thing from no drive key locking pully/gear to slack bolts allowing gear to fall of after rebuild at reputable firms (it only takes tech to get distracted for a second)

a engine can be timed any way don't assume that the marks are correct I always put my own marks on when striping down
but as a rule of thumb no1 piston will be at top (or as ni on as makes no difference) when marks are aligned
how ever if it wont run/fire on easy start it sounds like there is a problem with compression which if has been running over at strange angle would be my 1st guess

I wonder, had some sort of keeper worn when on a big angle allowing the timing to shift
Have you tried sticking your thumb over a injector hole (the hole in the head when a injector is out) just to make sure you have compression still

I would also expect to see smoke out the exhaust even if compression was shot

It sounds like your timing is out

If the smoke isnt coming out the exhaust and your sure theinjectors are firing weres the fuel going

Is there smoke or fuel smell on the air cleaner side

If you give it a squirt of aero start does ar least rattle a bit ? If so it would indicate you still have a fuel problem as in lack of fuel

I trust you have wound it over with injector lines are cracked till a good fuel supply is coming out of each ?

Paul