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720 Diesel

J

John 37A

Member
We are working on a black dash 720 diesel and had it on the dyno yesterday. At a free high idle it would not rev up to pto speed (tach on tractor is not working). About 510 pto rpm is all I could get. When pulled down to a load, it made 58 hp at about 450 pto rpm. At free high idle, it has a bit of a miss, like it's cutting back on fuel. Any ideas on what to try?

Thanks,
John
 
There is a procedure in the service manual to set up all the linkage and governor. I'd start by going thru it step by step.

And 58hp @ 450 pto RPM does not really mean anything unless you are using the conversion chart for that model dyno. The direct reading scales on the gauge are set for 540.
 
(quoted from post at 10:53:50 10/17/14) There is a procedure in the service manual to set up all the linkage and governor. I'd start by going thru it step by step.

And 58hp @ 450 pto RPM does not really mean anything unless you are using the conversion chart for that model dyno. The direct reading scales on the gauge are set for 540.
Click to expand...

I'll check it out. Waiting on my service manual to get here. Just checking to see if there was anything obvious that I might have missed in quickly looking it over.

That 58hp was using the conversion chart, not the hp gauge.
 

I assume you have already looked at the Throttle Lever Stops and you have no adjustment left there.?

As the governor cuts the fuel back, they sound somewhat different..they can be very RPM sensitive when going down a hill, on the road..

Ron.
 
(quoted from post at 00:01:40 10/18/14)
I assume you have already looked at the Throttle Lever Stops and you have no adjustment left there.?

As the governor cuts the fuel back, they sound somewhat different..they can be very RPM sensitive when going down a hill, on the road..

Ron.
Click to expand...

I believe the adjustment is right. The governor seems sluggish (I've killed the tractor a few times by easing the clutch in at low rpm- something that I feel shouldn't happen) at low speeds and there is a definite sound difference like it is cutting fuel at high idle, which is somewhere around 500 pto rpm.
 
This tractor has a fass fuel system on it rather than the stock lift pump. Both filters are new and the system provides plenty of fuel. I would like to return to original setup soon. I will check pressure though.

Thanks to all for the advice so far. This site is wonderful for stuff like this.
 
I believe your concerns can be answered once you have obtained SM-2020 (12-57) and have read section 40...40-5-1 to 40-10-11. There is a lot of information to be aware of to pin point the problem and then to take corrective measures. I would verify the FLYWHEEL is properly oriented to the crankshaft. Picture 40-10-11 can be only verified once picture 40-10-16 has been verified.
Bob...
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