186D bleeding?

Mith

Active member
Ok guys, I'm having trouble with a 186D.

Changed the fuel filter and the engine wont start. Reckon its just pulled air into the injection pump.
I cant see any fittings to bleed air out of the injection pump. Its a gravity feed system, and doesnt seem to bleed itself.

I've done it once before to this tractor, but it involved lots of mess and forcing fuel into the injector pump. I cant believe thats the right way to do it.

Any thoughts, or am I barking up the wrong tree?
 

ghautz

Member
From what I have read on other Yanmar forums there are probably a couple of bleed screws between the filter and the injector pump. On my 1500D, they are 10mm hex heads with philips drive slots. I just open the closest one until there are no bubbles in the fuel leaking out, then go to the next and do the same. The tractor starts with no trouble.
 

California

Super Moderator
Staff member
Site Supporter
From what I have read on other Yanmar forums there are probably a couple of bleed screws between the filter and the injector pump. On my 1500D, they are 10mm hex heads with philips drive slots. I just open the closest one until there are no bubbles in the fuel leaking out, then go to the next and do the same. The tractor starts with no trouble.
That's my experience too. My Yanmar has two bleeder screws on the fuel filter and one at the injector pump inlet banjo. The manual says bleed them one at a time working downstream, ie first the bleeder at the filter inlet, then at the filter outlet, then at the pump. And you never need to bleed at the injectors. This has always worked perfectly for me.

Here's a picture of a filter assembly I bought off a VN "factory rebuilt" Yanmar. It turned out to have some bogus, unavailable element and bowl on it.

Alongside the bogus soft parts are a new genuine filter element and bowl that are correct for all the YM's up to about 25 hp. Larger Yanmars have a similar, longer element and bowl.

The two bleeder screws are obvious at the top of the filter housing.

IMG_3186rFuelFilter2.jpg
 

Mith

Active member
Cheers guys.

So there is only one bleeding screw on the injector pump which will be on the banjo connector where the fuel line attaches?

I'm getting a nice flow out of the filter, but nowt seems to go into the injector pump. There's only about 1/2 gallon in the tank, so the level might not be high enough to provide the gravity flow to the injector pump.

I got it going once by holding a tank high above the inhector pump. Re-connected it back up to the filter. It ran fine but then I turned the fuel off, forgot to turn it on and fired it up and put myself back to square 1. Bugger.....
 

California

Super Moderator
Staff member
Site Supporter
Cheers guys.

So there is only one bleeding screw on the injector pump which will be on the banjo connector where the fuel line attaches?
That's the case on Yanmars a little older than yours. And I've never heard of anyone having a problem after bleeding as I described.

I'm getting a nice flow out of the filter, but nowt seems to go into the injector pump. There's only about 1/2 gallon in the tank, so the level might not be high enough to provide the gravity flow to the injector pump.

I got it going once by holding a tank high above the injector pump. Re-connected it back up to the filter. It ran fine but then I turned the fuel off, forgot to turn it on and fired it up and put myself back to square 1. Bugger.....
Maybe it's sucking air and losing the prime? I've read of cracked fuel bowls, and of course that o-ring needs replacement occasionally because they tend to harden. Plus if the fuel line has been off, it might not be airtight.

I love my Yanmar! I simply never have hassles like this. Does that model 186 have an electric shutoff solenoid or something that adds complexity?
 

Mark777

Member
Jim,

ghautz and California nailed it.

If there were a list of things one might dislike about a Yanmar it would be owning one and running out of fuel.

Cracking the injecor lines at the cylinder head does NOT work on a Yanmar direct injection engine. Purging air before the injection pump is the only way to get the beast to start....

It's really fairly simple once you've done the one, two, three method and as mentioned above...this is how it has always worked for me:

The fuel tank should be nearly full to speed the process.....

On the fuel filter valve body (two 6mm/10mm head cap screws)-lossen the top left screw and allow a full, sloppy and miserable 10 seconds for fuel to dribble all over your tractor. Snug cap screw closed and proceed to the next (right) screw and do exactly the same thing. Proceed to the fuel injection banjo fitting and do the exact same thing.

It will start every single time when one follows this simple but tried and true method.............unless :( 1- you have a weatherd/cracked fuel supply line, 2- pinched or broken fuel jar "O" ring, 3- chipped, cracked or warped (plastic) fuel filter jar.

Good Luck - Mark
 

Mark777

Member
California....

The 186D does not have a lift pump or electric solenoid. It's equipped with the mechanical fuel valve body....nearly the same as yours (maybe a little smaller??).

Mark
 

Mith

Active member
Well, when I loosen the fitting on the inlet to the injector pump noting comes out no-matter how long I leave it. Fuel is coming out on the filter as expected. If I take the pipe off and hold it lower down fuel comes out, so the level in the tank must be lower than the injector pump. Simple solution, fill the tank up :D
I did find a split fuel line which I replaced.
I'll let you know how it goes, thanks.

Quick question, has anyone got an article explaining how the powershift works?
 

Mith

Active member
Cheers guys, got it running today. Primed the injector pump by putting fuel in under pressure (giant syringe) then connected it up the the filter, bled the filter and away it went.
I could have just filled the tank up, but I didnt want to do that on my dime ;)

Anything on powershift?
 

Mark777

Member
Jim,

It's a pump.....a pump not associated with the tractors hydraulic system or dependent on the exterior hydraulic pump that powers the 3PH.

The rumors about it being bullet proof are quite true as they were developed for Japans "Rental" equipment industry and that's how idiot proof they actually are.

Here's a pic' from my parts book of the innards' of the YM186D power-shift pump:
 

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