4520 Rev-Up At Cranking

[Budinohio]

All of Deere's farm tractors and combines in the late 70s and through the 80s (don't know about now) started this exact same way. I always got 3-4000 hours before an overhaul was needed. Hope this eases some minds, bud.

 

[gabby]

</font><font color="blue" class="small">( All of Deere's farm tractors and combines in the late 70s and through the 80s (don't know about now) started this exact same way. I always got 3-4000 hours before an overhaul was needed. Hope this eases some minds, bud. )</font>

My 7600 has over 5,000 hours on it and the engine is still in good shape. Cranks well, uses very little oil, clean exhaust. It does have the cold weather fuel boost button on the inj. pump that causes a quick rev up but it turns enough revolutions before firing to get some oil moving. The 4520 fires very quickly and immediately takes off to high rpm's. I will be very disappointed to be needing at an overhaul in 4,000 hours or less on it. None of my other tractors have any kind of throttle override for startup.
gabby

 

[EquipmentJunkie]

I experienced the same start-up scenario when I test-drove a 4320 at a trade show a few weeks ago.

When the engine first fired and raised to the higher rpm, I thought I did something wrong. I was flustered and quickly scanned the instrument cluster to see if I had set the throttle to 3/4 position by accident. The engine dropped to normal idle speed about the time that I determined that there was nothing that I did to cause the situation.

I said something to the Deere zone rep that was working the show. He said that they all do that at start-up and Deere will be correcting this issue in the future.

I agree with you about being concerned with the overall wellfare of the engine. It goes against everything that I have been taught and researched on correct engine start-up. I just don't like the high speed, "dry fire" start.

All this being said, don't those new, Deere engines sound fabulous?

 

[green4710]

I test drove a 4720 when they first appeared on the dealers lot, and when it revved, I thought I had a setting wrong also. My dealer just came back from the factory, and said the reason they rev like that is for oil pressure. By revving it, the oil pressure comes up fast, and voila. I dont think I agree with that. Cold diesel engine, generating a lot of heat and rpms all the sudden. Can you imagine a semi with a huge cat diesel doing that when you start it???? I wouldnt want to be around.