Combines Smokin 750

[Rockpicker]

Yes it is normal. My grey cab 760 smoked pretty good and I bought it new. My neighbor's 850 smoked pretty good too. The truck drivers could always tell were I was.

 

[dav11]

I have had the same thing with 860 with 354, took 2 years to figure it out, had problem where it didnt have the power it should, and so much smoke it looked like you were burning used tires there was so much smoke, took injection pump to one repair shop and they kept telling me there was nothing wrong and telling me all these other nonsense things to do and nothing worked, then took it to someone else and he found that the scribe mark on the base of the pump was off 8 degrees- therefore if its off 8 on the pump it is off 16 degrees to the motor, after enough use the gears that run the ijection pump can wear ever so slightly and some on each one adds up to enough to get the timing off, I would try to loosen up the 3 bolts on the base of the pump and turn it to one side or the other slightly and see how it performs then, just wanted to let you know what my experiences have been-- good luck.

 

[ski_whiz]

Yes, you're right about the timing. Extra or correct advance helps to burn the fuel. We normally correct the timing with the Perkins marking angle tool. The wear in the gears can't always be corrected by moving pump, but Perkins built a solution into the drivetrain of the pump. The gear in the timing cover which runs the pump has slots in it and you can also remove it and jump it a tooth if necessary. I've had to do this many times - most common tune up issue on 354 with higher hours. It also may be overfueled, as these machines are underpowered. In this case I normally advance the timing slightly past factory spec. to help start the burn sooner. Shame to waste that fuel, but the power is nice. Check for these other things as they can also cause or contribute to the smoke. -Injection pump leak into engine, loses case pressure,affects timing -Dirty fuel lift pump_poor pressure -Air filter_Intake_Turbo condition -Injector nozzle condition The engine of the combine is most times the least maintained part. Don't forget to set your valves too. Remember, this thing runs wide open under maximum load for hours on end - give her a treat sometime.

 

[Jas]

This combine has just over 2700 hours on it. Is this enough for the gears to wear like you say they willIJ I am going to pull the injectors and have them checked out first. like I said, this combine runs good and starts good until it gets around 50 degrees outside, then I have to use a snort of ether or crank for a long time. I have a neighbor that has a gear drive 750 with an 18 ft. head and his smokes too but not as bad as mine.

 

[dav11]

There could be a number of things causing excessive smoking, to check turbo charger I would take off air intake hose on the left side and see if the shaft the fins are on is tight or if it looks like the fins have been rubbing the housing,the shaft the fins are on should be tight,if you have never done anything to the injection pump itself its very possible that it may have some worn parts, I had mine gone through at about 2200 hours and there were a number of parts that needed to be replaced, it is possible that the gears running it do have a degree of wear and are creating a situation where the timing is somewhat late or not where it should be,On mine it would die in the field and couldnt figure out what was wrong and they kept telling me to try every silly thing imaginable, the dealer I work with simply didnt know,I finally found pump repair shop that helped me with it, I am not mechanic, its just things I learned the hard way-- experience. I also put on a electric fuel pump that pumped 10 gallons a minute and one pump repair shop told it was dieing because it wasnt getting fuel-- nonsense-- it was overfueling that is why it smoked so much, mine also does start hard once it gets about 40 degrees or colder,I dont like to use ether, I usually use WD40 because it has propane in it, ether is not good for an engine, be sure not to use any more than you absoulutely have to. What solved my problem more than anything was to get the timing where it needed to be. It will start and run good even if the fuel pump is out of time, but will smoke excessive and not produce power it should, however they do smoke somewhat, but mine looked like you were burning used tires which it shouldnt do.

 

[ski_whiz]

The problem is the design of the geartrain, including the right angle the pump is mounted on. As far as hours, it probably depends on how well it's been maintained, as this would affect the wear. If you have the marking angle checked on the pump at an older MF dealer (most of them had the tool, or at least we do),this can also check the condition of the pump shaft seal. The last engine that I had this problem with was an MF 3650 tractor, 2800hrs, smoking and down 15hp from spec. - I had checked everything, the guys geartrain was mint, not worn at all when I checked the angle on the engine, Injectors didn't even need to be adjusted. When I checked the angle on the pump, I left the pump on the tester over lunch. When I came back the fuel had leaked out the shaft seal all over the bench - lucky, as the problem then became very clear. The case pressure had been leaking out this seal and changed the hydraulic advance inside the pump - once repaired, along with a thourogh tune up, the problem was solved and the hp was slightly above spec. Don't rule anything out, the improvement in fuel economy alone may pay for it.