Yanmar YM2000 Fuel Pressure/ hard starting

[Indirocz28]

Have been scanning hard starting threads here.
Have a Yanmar YM2000BD.

It seems hard to start most of the time except when warmed up.
I figured at first Thermostart was bad, which it was, I致e since fixed that with a new one, and it works well!

Ambiernt temperatures here are high 70s and up to the high 90s currently.

Anyway, so when I got it home from testing out when I bought it, it wouldn稚 re-start and ran the battery dead.
Just lots of cranking and some white and black smoke. Finally I noticed the fuel bowl ring/but was not tight, so figured it was sucking air. Took fuel bowl off, inspected filter and o-ring, all look good and clean, put in square and ring but went on straight and tight all the way to the top. Bled the screws on the filter housing, the screw on top of the banjo bolt on top of the pump, and then cracked the lines at the injectors, and craned the engine over until some fuel was dripping from the cracked injector lines.

Tightened injector lines back up, let the tractor battery sit on the jumper cables from my truck for about 15 mind, pulled the throttle lever back about half way, cranked with decompression lever out for about 8-10 turns then pushed it in, tractor fired right up.

Drove around the yard a bit that evening testing things out some more, and then parked it in the garage.
Next two days, get home from work and decide to start it and play with it a little bit. Both days second try, tractor fires right up and ready to go.

Third evening, back to crank crank crank and no starting again. Same thing for the last 3 days, it痴 just sitting in the garage stuck there taking up space now. I致e gone through the bleeding procedures each time, and no change.

Today I pulled the lines out of the injectors and while cranking it over noticed what seemed to me like very weak fuel pressure coming from the pump for a diesel.

I値l try to attach the video here.

 

[winston1]

No, that would not necessarily be weak. the pump just has a small plungers that pump a very small amount. But when you constrict that small flow the pressure becomes great. With an open line that is not evident.

 

[Indirocz28]

No, that would not necessarily be weak. the pump just has a small plungers that pump a very small amount. But when you constrict that small flow the pressure becomes great. With an open line that is not evident.

Okay good to know!
I just know on the pickup, and especially my old Dodge if you had a line loose, you knew it!

 

[Indirocz28]

Not sure if this helps any. Just got the new muffler put on a few minutes ago.
Bled fuel lines again still doesn’t want to start. Am I just not finding the sweet spot for a/f mixture with the throttle lever?

 

[winston1]

Should not be a sweet spot. Wide open should work if hard to crank and then idle down when she cranks. How long have you had the tractor and how long has this hard start been going on? Low compression on these makes for hard start.

 

[California]

Are you cranking with compression released, then dropping the compression release and continuing cranking with the inertia of the spinning flywheel assisting the starter? That's all I can think of.

 

[Indirocz28]

Are you cranking with compression released, then dropping the compression release and continuing cranking with the inertia of the spinning flywheel assisting the starter? That's all I can think of.

I am opening compression release, getting it spinning then pushing it closed.

Anywhere from half to full throttle.

Winston, I have only had the tractor a week. When I bought it, it cranked for 30 sec or so and fired up. I tested it out a bit, shut it down. In short the day I bought it before I took it home I started it 3 times, and each time about 30 second crank and off to the races.

I did just drain the fuel tank, and took the fuel bowl off to empty it. The fuel has been in there since this spring according to the PO. There was some trash in the bottom of the filter, but the tank looks good.
I’ll put a fresh filter and fresh fuel in it tomorrow.

I am quite mechanically educated, at this point I am fearing the worst, just hopefully it isn’t. Looks like a good place to start is to check the valve spec as well. I’ll probably do that this week, and I guess order the compression test adapter from Hoye. I already have a diesel compression testing kit from working on diesel trucks.

 

[kenmac]

Just a suggestion.. Make sure the compression release is closing all the way.
All these things need is good fuel and good compression to get started

 

[thepumpguysc]

Whats the pressure AT the inj. pump inlet?? It does have an electric pump doesn't it??
Loosen the INLET LINE AT the inj. pump , turn the key on & SEE if it has fuel or bubbles, immediately after turning the key..

 

[California]

I have only had the tractor a week. When I bought it, it cranked for 30 sec or so and fired up.

That's not normal.

Warm weather and Thermostart used, these will fire and run on the first complete intake/compression cycle.

Worse than ideal conditions, maybe a few stumbling strokes (keep the starter assisting it for a few seconds).

Here's an example, a sound file I posted long ago. Temperature chilly, 50 degrees. It fires and runs on the third TDC.