Yanmar 155D running like crap

[careyo63]

Oh. Mine is metal. It is a big problem with old tractors and motorcycles that have not had their tanks full. The condensation is the problem. My friend has an old IH tractor that the fuel line keeps getting clogged with rust from the tank.

Had bikes all my life since I was 12 except for now. First was a good ole XR75. I went down Phys. while on one. It wasn't good!! Here's what I did to prevent condensation and actually back pressure. I seen air bubbles coming out around the Injector return on the tank and new that wasn't a good thing. Came off a old Kawasaki 220 Bayou. Just drilled a hole in my cap and works great. Took care of that potential problem.

 

[thepumpguysc]

That's a slick fix, right there..

 

[Jtullis13]

Condensation is a big problem for any metal fuel tank. I didn't think any of the Yanmars had metal tanks, but if they did I would keep it as full as possible. Use some sort of fuel treatment too, there are plenty of different kinds out there.

 

[chevy791979]

I had a delivery valve spring on #1 cyl that was missing since the tractor was new. It smoked like **** and one hole wasn't even injecting fuel. Long story short, I'm the 2nd owner and the original owner said it ran like that since he bought it. It started hard and smoked like a freight train. I found the the #1 delivery valve spring was missing. Got two delivery valve springs and valves and it runs like a champ. Also put new injectors in it

Check your spray pattern on both cylinder and see what that tells you after you determine the hole that is "dead"

 

[thepumpguysc]

This thread kinda got hijacked.. What happened to Docdox.?? Did u figure out the problem.??

 

[careyo63]

Seen this last night and thought the same. My guess why was to me pretty much two things. #1 He found the problem which I think he did. #2 The big one. Having to figure out how check the compression. With most Comp. testers having any Threads that will work. That would have been a guestion on here for sure And if he did find them Low or No!! We would have heard something if it was similar to #2 I'm sure. Sometimes no news is good news. And it all so seems there is a lot of things done and talked on PM. Just sayin..............

 

[rScotty]

This thread kinda got hijacked.. What happened to Docdox.?? Did u figure out the problem.??

I wondered that myself. Looking back at the first post I see one thing that we overlooked when Docdox wrote,
" I have to run it up to 3000 rpm just to move it and when I till it spews black smoke. Meaning it has unburnt fuel which leads me to believe it's a bad cylinder not an injector."

Doc, that's not correct. Black smoke doesn't necessarily eliminate the injector. In fact, an injector that is squirting liquid instead of a making a aerosolized spray (as it should) is a common way for injectors to go bad and will certainly make the engine spew black smoke from unburnt fuel.

You can check the injector by removing it - which can be very difficult to do and I'd check some old discussion threads here & maybe buy the special tool.
Anyway, when you get the injector out, you can hook it up, crank the tractor, and see how the injector patterns against a piece of cardboard held a few inches away. Try not to inject your skin with high pressure fuel, big health problems from that, but easy to avoid.
Good luck*
rScotty

* I've noticed that most of the time good luck beats good planning....

 

[clemsonfor]

I have a Yanmar 155D that I use for tilling my garden. Last couple of years it has progressively weakened and now it is very hard to even get it started. I am going to do some checks on it and see if maybe it has a plugged injector but I believe it has a bad cylinder. I have to run it up to 3000 rpm just to move it and when I till it spews black smoke. Meaning it has unburnt fuel which leads me to believe it's a bad cylinder not an injector. It has over 1000 hours on it so probably due for an overhaul anway. One other thing I noticed, when I pulled the air cleaner there was a bunch of diesel in the bottom of the cap. Not supposed to be there........

I know I'm late to this but 1000 hours on that motor is nothing!! With care it should of lasted three to six times that long easy

 

[clemsonfor]

Filling your diesel tank halfway is the best way to rust a fuel tank.

That would be true. But these tractors have plastic tanks. Haha

 

[duanew1]

That would be true. But these tractors have plastic tanks. Haha

Mine doesn't. It is a YM2001 though.