1610D throttle and white smoke

[Eric5444]

I recently got a 1610D from a container shipment. For the guys unloading the container and assembling their tractors it was like Christmas in March! Great fun. The tractors turned out to be pretty good as well, one 1702D looking practically showroom new.

My 1610D seems to be in great shape too. 550 real hours (a four digit meter); nice paint, no leaks, etc.). It looks like a lovely replacement for my 1300D. But onrunning it I have had a issue come up on which I could use some advice.

The throttle seems to have a kind of detent stop indicating when it is pushed to an off position, but you can easily push it further past that point. When I turn the machine off and go past the detent point (as the engine runs fairly rapidly) it makes a kind of fluffing sound, a lot of white vapor comes out of the exhaust, and it keeps chugging. If I shut it down by pushing only as far as the detent it stops normally.

What's going on here? What's the purpose of the detent? Is there any good reason to push the throttle past the normal shut down point? Your advice would be much appreciated.

 

[kayssupply]

On any Yanmar I have had that doesn't have a fuel shut off ,located on the right just below the throttle, the detent position is the normal idle position. You push past that to kill the engine.

There is a locknut and adjustment at the pump to adjust the idle/ kill.

 

[Eric5444]

Thanks for the reply. It makes good sense that the detent position would be there to make it easy to go to a good idle speed. What is still unclear to me is the meaning of all of the fluffing and emitting of extra fuel as white vapor when I go past that mark. Any ideas?

 

[normde2001]

Eric, I believe you said it shuts off in the idle (detented) position. Sounds like it's just not running up to snuff. Have you done normal maintenance, check/replace air, fuel filters? Possible water in fuel, or clogged air filter. If OK, follow the linkage and see if a problem with fuel shutoff mech.
Norm

 

[roger_scotty]

The throttle controls the "throw" of the fuel pump....That regulates the total stroke on that pump and is adjusted with shims on some models. I'm wondering if yours has that adjustment out of whack. It is hard to explain, but easy enough to see in any of the Yanmar shop manuals of the later 1980s for the US models. They go into detail with illustrations. Take a look at them and maybe you can see a problem. I know that mine required some adjustment by the DPO and I still haven't gotten it quite right.
Hmmm...yours doesn't happen to have a connection that pulls the compression release when you pull the throttle all the way back does it? I've heard of that but haven't seen it on the US models. That's worth a look. You would see it as movement in a shaft that goes through the valve cover when the throttle is all the way retarded. A wild guess, but it would sure cause the symptoms..

 

[Eric5444]

I have done the normal maintenance: new oil and filter, made sure air filter is clean, drained and replaced fuel and fuel filter. The engine seems to run fine--as long as I don't push the throttle past the detent point--so I don't think it is a general problem of poor running, though I could be wrong.

As to Roger's suggestions, it was interesting to learn how the throttle works. I'll have to think about the shim point but I notice that if I push the throttle to the detent it shuts off nicely, making me think it is adjusted about right. I'll have to check later to see if pushing the throttle way forward opens the compression release. Since I've done this when the engine is going at some speed the symptom of unburned diesel oil coming out of the exhaust would certainly be explained by that idea. On the other hand, it seems to keep on chugging and is unwilling to stop. Anyway, will check that out when I get home.

Thanks to you both.

Eric

 

[roger_scotty]

Erick, as I read back through these messages I'm not sure that Norm and Reed and I communicated successfully that the detent is not the "shut off" position. The detent is the normal idle position. One pushes past that point to shut the engine off. I hope that yours turns out to be a compression release, that's easier to deal with than the fuel pump. But since it isn't idleing at the detent place then I'll bet you end up adjusting at the pump. One other possibility for it turning off at the detent point is that the throttle friction plate (which carries the detent, spring, and ball) is adjusted wrong, though that still wouldn't explain why it goes into "snort mode" when you push past the detent. As far as I can see, snorting like that could only be: 1. compression, or 2. the stroke of the fuel pump.

 

[kayssupply]

I had an Iseki with electric/key shutoff. It went bad. I tried to put a manual shutoff valve in line. It snorted and coughed like he describes when I used it. It cost $440 to fix that one with the OEM part.

 

[Eric5444]

Thank you Roger and others for your continuing and help. I get the point that the detent point for the throttle should put the machine at idle, which it is not for my machine. Perhaps the fuel pump needs adjusting, as you suggest. "Snorting" mode is a wonderful (and accurate) description for what it does when pushed past the detent point.

My machine also seems to ping too much when under load, at least at less than high throttle. I gather this might be an injector timing issue but perhaps it could also be related to misadjustment of the fuel pump. Guess I'm going to have to haul it in to a local shop. Thanks again for all of your help.

Eric

 

[roger_scotty]

Eric, I'm assuming that yours doesn't have the ignition key shutoff that Reed is talking about. Some do, but it is rare in Yanmar. I did not include that in my short list of possible problems, and don't know anything about them.
I'm not understanding what you mean by "ping". All diesels knock and just between us Yanmar owners, some of the Yanmars are real "YammerHammers". At some RPMs, The two cylinder models can make a noise that sounds like hammers on a steel drum. Three cylinder models are less noisy - particularly at idle. But none of these sounds are like the ping of a gasoline engine when climbing a hill under too much throttle.
I wonder if it could be the fuel? Too much additive or something volatile in it would explain everything. Have you tried simply dumping that fuel and putting in some fresh?