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?