YM1700 injector timing question

[goose117]

Hello - I've read through many of the injector timing questions and answers but am finding my attempt at checking the timing confusing so I'm thinking I'm interpreting the instructions incorrectly.

My process has been to remove the injector lines from the injectors, manually turn the engine, then watch for fuel to come out of the the injector lines. The fuel just sorts of barely dribbles out of the lines at certain points during the engine rotation.

What I have got so far is that the rear (#1) injector line (see photo), connected to the front port on the injection pump, seems to output fuel when the timing pointer is between the #2 TDC and #2 timing mark (see other photo). This doesn't make sense to me. I checked and this is when the rear cylinder is at the top of its movement.

Can anyone help clarify if I need to change my method or interpret these results in a way that seems consistent with aiming for the fuel to be injected 22 dg before the #1 TDC timing mark? I've also included the instructions in the manual I have.

One other question - does the injector timing that is done when adjusting the governor effect where injection occurs per these timing marks?

Thank you.

 

[winston1]

I personally like the method given in the I&T manual for the 195 which would be the same as your 1700.

 

[goose117]

Thanks! This has more detail so I will give it a try.

 

[thepumpguysc]

Quick note but very important…
Where it says remove the delivery valve .. they mean THE CENTER of the dv.. NOT the entire thing..
Good luck

 

[goose117]

So I took out delivery valve and spring from the forward (#1) pump port then attached a clear tube. When I turn on the fuel at the fuel filter the tube fills up to the height of the fuel in the gas tank. However when I turn the engine over manually (CW) or turn over with the starter (injectors are removed), I don't see any movement of fuel in the clear tube. I know with the injectors attached they fire regularly so I'm wondering why I don't seem to see any fuel being pumped from the injector pump (making sure the fuel is turned on)? The pictures show the parts I've removed and the clear tube setup for monitoring the fuel coming from the pump.

 

[thepumpguysc]

Do u have the throttle about 1/2 way on and not in the shut off position.?
It’s a throttle shut off and not an electric sol. right.?
Put the throttle on 1/2 way..
If it’s electric, turn the key on.

 

[goose117]

Thanks for the suggestion. The throttle is all the way back (max open). Here's a link to a short video showing the lack of fluid motion in the tube with the throttle open and fuel on. fuel not pumping for timing check.mp4 (not sure if this is how videos are shared here).

 

[thepumpguysc]

U have the decompression lever on..!!

 

[goose117]

I have the injectors out so that's why there's no compression. I didn't take them out for the timing check but they just happen to be out while I'm doing this.

 

[California]

Pumpguy knows far more about this stuff compared to us amateurs but I'm not bashful about sharing an uninformed opinion .

I think the amount of fuel expelled per injection, every two revolutions of the crank, is so tiny that the vibration of the engine being cranked, has a far larger effect on the level in that transparent tube. And - look at the turbulence where the tube is connected to the engine. Something is going on there. Looks to me like bubbles.

So - I don't think the level at the upper end of the tube is telling us much. Pumpguy?

 

[goose117]

Thanks for the input. Yeah there are some bubbles there at the outlet. I could try greatly reducing the tube diameter so any change is more visible. Your comment about not really seeing a change because of the small amount of fuel pumped per cycle makes sense.

There don't seem to be bubbles in the line from the fuel bowl to the pump and I did bleed the connection at the pump.

 

[bmaverick]

Thanks for the input. Yeah there are some bubbles there at the outlet. I could try greatly reducing the tube diameter so any change is more visible. Your comment about not really seeing a change because of the small amount of fuel pumped per cycle makes sense.

There don't seem to be bubbles in the line from the fuel bowl to the pump and I did bleed the connection at the pump.

I once ran the YM2610 out of fuel. I recalled Aaron's bleed procedure on YT. Watched the video and yes, these Yanmar fuel sipping machines make lots of power and use small drops of fuel to run.

While I was bleeding each line, I had to check and recheck as the droplets were not that big. Once done, The lines went back on. Started and cranked over normally. It's not like a gasoline engine where you would expect those injectors to shoot a large mist.

Could I also assume, you had downloaded the Yanmar 2T & 3T fuel pump service manual from the YTOG?

And, did you watch Matt's YT vid too,

 

[thepumpguysc]

U might b in the “starting fuel notch” with the throttle all the way open.. try pulling it back to half..

 

[California]

U might b in the “starting fuel notch” with the throttle all the way open.. try pulling it back to half..

What's that?

YM240 Manual says to start at full throttle but I never understood why, and actually use about 1/3 throttle before it catches.

Comments?

 

[goose117]

I once ran the YM2610 out of fuel. I recalled Aaron's bleed procedure on YT. Watched the video and yes, these Yanmar fuel sipping machines make lots of power and use small drops of fuel to run.

While I was bleeding each line, I had to check and recheck as the droplets were not that big. Once done, The lines went back on. Started and cranked over normally. It's not like a gasoline engine where you would expect those injectors to shoot a large mist.

Could I also assume, you had downloaded the Yanmar 2T & 3T fuel pump service manual from the YTOG?

And, did you watch Matt's YT vid too,

Thanks for the input. I don't have a good feel for how much fuel is involved per firing. I do have some recent videos of the spray patterns from the injectors. It looks like a lot but probably isn't. Here's a short video short injector spray.mp4

I have watched Matt's governor adjusting video a few times. I haven't seen anything about how this governor adjustment and the timing adjustment I'm attempting now together effect the overall injection timing.

I haven't seen the pump service manuals but will look for them. I have a 240D manual that came with the tractor.

 

[goose117]

U might b in the “starting fuel notch” with the throttle all the way open.. try pulling it back to half..

I tried a couple of different positions but it didn't seem to make a difference.

 

[bmaverick]

Thanks for the input. I don't have a good feel for how much fuel is involved per firing. I do have some recent videos of the spray patterns from the injectors. It looks like a lot but probably isn't. Here's a short video short injector spray.mp4

I have watched Matt's governor adjusting video a few times. I haven't seen anything about how this governor adjustment and the timing adjustment I'm attempting now together effect the overall injection timing.

I haven't seen the pump service manuals but will look for them. I have a 240D manual that came with the tractor.

Compliments of the YTOG, see attached. Wish the images were better.

Before ever tearing into the fuel pump, there are plenty of things not to touch if you never done this work prior, ask @thepumpguysc who's been in this thread from the start. He's a master rebuilder on these fuel pumps. Having the fuel pump, governor, spray pattern and timing all just so will make it all work together.

 

[goose117]

Compliments of the YTOG, see attached. Wish the images were better.

Before ever tearing into the fuel pump, there are plenty of things not to touch if you never done this work prior, ask @thepumpguysc who's been in this thread from the start. He's a master rebuilder on these fuel pumps. Having the fuel pump, governor, spray pattern and timing all just so will make it all work together.

Thank you! There is a lot of good information in there. One thing I noticed is that the delivery amounts are around 25 cc per 1000 strokes, or 0.025 cc per stroke. For my 1/2 in ID monitoring tube, 0.025 cc is only a length of 0.008 inches, if I multiplied and converted correctly. If I used a 1 mm ID tube I might get around 0.3 in or so of change in the length of tube fill. With a 0.5 mm ID tube there might be about 1.2 inches.

 

[thepumpguysc]

I think you’re thinking about this wrong..
The fuel is supposed to be flowing out of the #1 cyl under a bit of pressure, not under gravity flow..
And when the engine is turned slowly, it SHUTS OFF.
THAT is the “start of delivery”..

 

[goose117]

It does sound like I'm not following what is happening correctly. It seems like the fuel will flow out of my monitoring tube if I put the open end below the fuel tank level at least for some part of the engine's cycle. Maybe this is OK and I rotate the engine till the flow stops and this is when I check the timing? Is this closer? Thanks for all your input on this!