Yanmar FX 335-hard to start and sounds like it's missing at low rpm.

   / Yanmar FX 335-hard to start and sounds like it's missing at low rpm. #21  
Ok guys,we all know that synthetic oil will not cure his problem,and I did not say it would.
I added Amzoil to my engine after the rebuild and I am happy with it, all my tractors run on it.
Now lets get back to helping this member get his machine back on the soil:D
 
   / Yanmar FX 335-hard to start and sounds like it's missing at low rpm. #22  
Ernie, I am sorry if it sounded as if I were criticizing your recommendation to run synthetic oil. I interpreted his comment to mean he would change the oil and see if that fixed his symptoms, which seems a waste of time and money to me. I didn't mean to be negative or harsh. I apologize for not saying things more carefully. It is good to see you around again/still!
 
   / Yanmar FX 335-hard to start and sounds like it's missing at low rpm. #23  
Looking back my remark about the oil was unnecessary and I apologize.
 
   / Yanmar FX 335-hard to start and sounds like it's missing at low rpm. #24  
No problemo.... I have a thick hide.

This tractor is going to be a bear to diagnose over the internet, specially since it has been tinkered with already.
I THINK this machine had an out of time injector pump, or it needed new rings, but someone muffed up the job....

All I can say is that we rebuilt our 335 in a day after getting the parts from Hoye tractor, and it smoked a lot less than when it came out of the container after the rebuild.
I run synthetic oil in my yanmars because I plan to keep them until Im an old geez ! :D
 
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   / Yanmar FX 335-hard to start and sounds like it's missing at low rpm. #25  
I stand by my statement on synthetics in this application and I also wasn't implying anyone was saying it was going to fix anything. :thumbsup:
 
   / Yanmar FX 335-hard to start and sounds like it's missing at low rpm. #26  
With TDP's permission I drove the 25 or so miles to his house to sneak a peek at his FX335. From the get go I do not want to bring into my comments anything about the shop that performed the repairs. They are willing to take it back and look again. I guess I'm just trying to say lets just concentrate on what his problem might be. I confess right off I don't know. Here we go. Tractor was cold when I arrived. I removed radiator cap, cranked tractor. Zilch on any bubbles, reinstalled cap. No water in oil or oil in water. During the whole 30 minute run the tractor stayed cool. Tractor busted off on 1st revolution. Temperature was about 50 degrees. A little smoke on crank up but minimal. Idled and revved just fine. A tad of a governor hunt but smoothed out pretty quick. Very difficult to get my digital thermometer to the same location on all 4 cylinders but to the best of my knowledge all 4 were about the same. TDP had a tandem disc on it and he put her down and probably run it 10 or 15 minutes. He was running in a pretty high gear so the tractor was loaded pretty good. Pretty good grey smoke emitting and I believe the longer he run it the worse that smoke got. The tractor ran smooth through the entire event with good power. This tractor had very minimal if any blow by out the crankcase vent during the whole run.

TDP was sort of thinking the tractor had used about a quart of oil in the last 10 or so hours and maybe has 50+ hours since the initially overhaul completed back in October. He wasn't real sure about the oil use and is going to monitor that a little closer. The repair shop has a dynamometer and have run his tractor pretty extensively on it. TDP doesn't really know any results.

His invoice shows 4 new injectors. The shop mentioned removing gaskets but after looking at his repair and parts manuals we believe the injectors actually are a metal to metal seal somewhat like some spark plugs. No gasket shown on the parts drawing and repair manual states if the seat is scratched the injector will have to be replaced. Said all that to say the parts drawing also shows a shim pack that goes in the injector. More or less shims ups or lowers the injector working pressure. We believe that is what the shop was talking about when removing gaskets it was probably shims. Don't know that, just assuming.

Injection pump has not been changed and was put back with the identical shims that was on it so I would think timing is correct. TDP's parts manual is for his FX335, he has 2 repair manuals, one for the ym336 and the other for numerous Yanmar engines. I may be wrong but I believe his engine is a 4tne78 and I think his manual skirts all around that exact model but just in the brief session I had with it I believe all the information is there for a good mechanic. These are the manuals Hoye sold him so I would feel pretty sure they are about as close as is possible.

I again confess I don't know the problem. Very minimal blow by would indicate good ring sealing to me. Oil use indicates otherwise? OK, lets just focus on what could be wrong and not on what the shop did wrong. Any ideas?
 
   / Yanmar FX 335-hard to start and sounds like it's missing at low rpm. #27  
Great write up, Winston. If it weren't for the oil consumption I'd suspect water in the fuel tank. Sounds like #2, a cylinder pressure check would help isolate the problem. Still, it wouldn't hurt to drain the fuel tank and check for water and algae crud.

From http://www.dieselenginesystem.com

gray smoke emissions cause and remedy
Gray engine exhaust emissions, fuel for machines that are part of the temperature is too low, oil and gas atomization bad, too late to burn the fuel to be discharged from the exhaust pipe. The main reasons for this phenomenon are:

(1) If the injection time of late, when leaking fuel injector fuel injection, injection pressure is too low, poor atomization, when the machine was too late combustion temperature is too low to be discharged to the form of white smoke.Approach, the correction of fuel injection time, check the injector conditions.

(2) lack of pressure within the cylinder. The cylinder liner, piston ring wear components, and the bad valve seals, causing the engine to take gray smoke when first started, and then with the machine temperature rise, into a light smoke or black smoke. Approach is to replace the worn cylinder liner, piston ring or valve repair, valve seat ring.

(3) diesel in the water. If, after the engine started emitting smoke gray, with the machine temperature rise, gray smoke still exists, then it may be too much diesel fuel mixed with water. Solution is to start a day before the fuel tank drain valve is opened, the bottom sediment and water discharge out.
 
   / Yanmar FX 335-hard to start and sounds like it's missing at low rpm. #28  
No problemo.... I have a thick hide.

This tractor is going to be a bear to diagnose over the internet, specially since it has been tinkered with already.
I THINK this machine had an out of time injector pump, or it needed new rings, but someone muffed up the job....

All I can say is that we rebuilt our 335 in a day after getting the parts from Hoye tractor, and it smoked a lot less than when it came out of the container after the rebuild.
I run synthetic oil in my yanmars because I plan to keep them until Im an old geez ! :D

Ernie, does your tractor still have a little smoke? And did the smoke get less with hours?
 
   / Yanmar FX 335-hard to start and sounds like it's missing at low rpm. #29  
Well Winston, Your the only one to actually see it so, you would have a better understanding of what is going on. If the smoke isn't a water problem. I ( just a guess) believe his problem is fuel related. What's your thoughts ?
 
   / Yanmar FX 335-hard to start and sounds like it's missing at low rpm. #30  
Well Winston, Your the only one to actually see it so, you would have a better understanding of what is going on. If the smoke isn't a water problem. I ( just a guess) believe his problem is fuel related. What's your thoughts ?

Really confused. No blowby, oil usage? Didn't notice in his parts manual about valve stem seals. TDF, why don't you look in your parts manual and see if it shows valve stem seals. Probably not the problem but it just came accross my mind.

One more thing I forgot was TDF said it started missing after he had run it hard 30 mniutes or so. This was with no load and maybe mid or less throttle. After talking with him about it I believe it was really not a miss but rather the governor hunting. He stated it went away if you decreased or increased the throttle. Didn't witness it myself so nothing definite.
 
 
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