Y385 Engine problem

   / Y385 Engine problem #1  
G

Grommit

New member
Joined
Nov 12, 2009
Messages
15
Hi all, I am new to the forum and hoping you can help me with a problem I have with a Siromer 30HP (for Siromer read Jinma) with a Y385 engine.

I have read through a lot of the posts and replies on this site and you all seem to be a very knowledgeable bunch of folks, here's my problem:

The tractor has been working well for about 5 years (about 1000 hours, clock packed up at 200!) with the exception of overheating in the summer when using a flail mower. Recently the engine stop rod inside the fuel injection pump governor lightly seized closed which meant the engine would not start (yes there was oil in the pump). I had to remove the pump to be able to open up the governor assembly and free it off, no big deal and it all works fine with no corrosion etc. The real problems started when I put the pump back on the engine.

After initially getting the pump timing 180 degrees out I finally got it timed in and it starts (with difficulty to say the least). Lots of cold cranking and it eventually fires into life with lots of blue/grey smoke and knocking - it will rev but eventually dies out at idle and is a rough as a Badgers bum. I have cleaned all the strainers; tank, banjo bolts and changed the fuel filter and double checked all the low pressure fuel lines but to no avail.

I suspected the injectors (new ones on order) but I am not convinced they are faulty now, each time I loosen the fuel pipe on each injector the engine note changes onto 2 cylinder running and the knocking reduces, more so on the front cylinder, but each cylinder does seem to be playing its part. The more I think about it I suspect it is air in the system especially as I can now see very tiny bubbles circulating round the fuel bowl when the engine is running.:confused: Could there be a leak on the lift pump? When I unscrew the plunger and pump it, some fuel comes out round the shaft and it does not seem to pump fuel back to the tank as well as I remember it doing when I ran out of fuel a couple of years ago and had to re-prime the pump. Could this leak air into the system and cause the problem I am seeing?

All advice welcome :)
Guy
 
   / Y385 Engine problem #2  
   / Y385 Engine problem
  • Thread Starter
#3  
Thanks Tommy, When I first got it going I had the timing too retarded and had loads of black smoke, I have since spent 3 days checking and re-checking the timing following the advice previously posted on here for setting up the pump. Now no black smoke just the problems I described.

I am as confident as I can be that the timing is now OK. I am going to re-check it tomorrow after a couple of days "thought time" but I really don't think its the issue now.

I am based in France so time wise I am a bit ahead of you so will update in your morning
 
   / Y385 Engine problem #4  
Here is a copy of a post I made some time back on general timing instructions for mechanical pump type diesels. This method should get you very close to right. I was a diesel engine mechanic for many years and used this method hundreds of times on various engines of different makes to include Indian, Russian, and Chinese military diesels.

You can set timing on most injector pump type diesels by removing all the injector fuel lines from the pump. Rotate the engine in the direction of rotation until you see the exhaust valve on #1 cyl close. Continue rotating the engine until top dead center is reached on the flywheel indicator. Now back the engine up (reverse rotation) about 1/4 turn. Put a little fuel into the top opening of #1 injector pump outlet (where you removed the injector line). Wipe off the excess fuel so the puddle on top of the pump outlet is concave. Very slowly using a pry bar on the fly wheel teeth, one tooth at a time, turn the flywheel in the direction of rotation, all the while watching the fuel puddle in the pump. As soon as the puddle moves the slightest amount, from concave to convex, stop and look at the timing marks. If your timing should be 14 degrees BTDC the flywheel marker should read 14. If it does not read correctly than most manufactures use slotted holes in the pump mounting flange to allow you to rotate the pump a little to adjust the timing, much like turning old style distributors.. After moving the pump and retightening it the process must be repeated. You can also do the inverse to rough set the timing. That is, set the flywheel to the proper advance mark and very carefully rotate the entire pump in the slotted mounting holes until the fuel puddle moves. You must then redo the first process for fine tuning.

Should the puddle not move by the time the piston goes past TDC on the compression stroke than you are probably 180 degrees out. The easiest remedy is to remove the pump turn the pump shaft 180 and reinsert and try again.

I have used this method hundreds of time and it has always worked well. It will only work on engines with inline or rotary piston high pressure unit pumps.
 
   / Y385 Engine problem
  • Thread Starter
#5  
Thanks for your post PSJ12, I had read your method earlier in the week and was doing exactly what you suggest.

I decided not to trust the very vague marks on the fly wheel so I removed the radiator, cleaned off the paint from the crankshaft pulley to reveal the timing marks; 0,10,20,30. To my amazement the timing was at about 40 degrees BTDC. I don't understand how I ever got it running, no wonder it was knocking, that far out all the fine adjustments I was making obviously made no difference. The adjustment on the pump gear and housing was not sufficient to bring it to 16 BTDC, I had to remove the pump gear and move it 2 teeth meaning that the teeth marks no longer line up as the manual states they should. It now starts at the flip of the key and I have been out cultivating this afternoon.

The lesson I will take from this is do not trust the fly wheel marks AND always worth going back to basics before looking at a more complex solution.

Thanks for your help, very much appreciated.
 
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