(800) 853-2651
SHOP NOW

7720 combine not making much wind

M

Moline_guy

Well-known Member
We have a 7720 that doesn't seem to be blowing air through the sieves like it should. New belt, it is running on top side of driver pulley and low side of driven pulley. Monitor in cab says it is running up to speed, but just doesn't seem to move much air compared to my 7700. Any ideas what might be the problem, corn husks just fall out of the back instead of blowing out the back, Thanks for any help or information.
 
At times like this look at the improbable. Worn belt? Pulley sheaves can wear to the point of allowing slippage? Monitor working correctly? They can be bothered by moisture. Fan housing not bent or restricted? Fan paddles straight? Cover between top of fan housing and lower auger pan in place and in good condition?
 
I bet it is slipping inside the driven pulley. Sometimes the "rails" on them adjustable pulley get caked up with old grease and dust and won't let the pulley go all the way in or out to keep the belt tight.
 
Check the roll pins in the pulleys. They like to break and only one sheave of the pulley will drive the shaft causing belt slippage. But all this is a non issue if the monitor reads the correct speed as the speed pickup is on the right side of the combine. Only other things to check is make sure the fan shaft is not spinning inside the fan. Also make sure you have the side shields in place.
 
I have had a few combines and a few problems with them but I am not experienced enough to help you. I go to the combine and chopper site {click on discusions on left and scroll down}for help. There you will find someone with the answer to your problem.
I would suggest that you check the curtains inside the machine.
 
Do you have a chopper on the back of the combine? Is the panel in place that directs the shucks into he chopper from the walkers? If not, that will let the shucks fall instead of being chopped.
 
Your combine should make enough volume of air that the shucks not attached to a cob should never even touch the chaffer. However, if they are attached to a cob your rear finger grate is damaged or else the curtain above the walkers is mounted too far forward and letting the cobs and shucks fall down onto the cleaning shoe. You should be getting at least 900 RPM on your fan speed. Any less than that indicates a problem. Also, be sure you aren't just getting shucks sucked into the fan intake due to very dry conditions in the field. Sometimes that happens and there isn't a lot you can do about that. Mike
 
I should have worded that differently, we don't have a chopper on it and the husks are coming off the top of the walkers, but aren't blowing off the walkers like the other combine. The husks are not on the sieves, but we are getting some pieces of cob stalks stuck in the front 1/3 of the top sieve, which the other combine has never had a problem with. Curtains both look fine, but didn't realize there are different settings for them. Looking from the side doors in, concave looks fine. I will have to check the pulleys again for grooves, but like I mentioned, belt is way up on driver pulley and low on driven pulley. Fan seems secure to shaft and no broken sheet metal and side shields are in place. This combine has an air chaffer top sieve and standing behind the machine with it running empty just doesn't have much wind coming off of it like the other combine with a standard sieve. The 7700 also has sheet metal plates attached to the wire fingers behind the augers and above the sieve, the 7720 does not have these plates.
 
That's what I thought too, but when I put the new belt on, the sheaves pulled all the way together when the old belt was removed, so I don't think that is the problem.
 
Fan looks to be good condition, sheet metal looks good, air vents to the back of fan are clean. I guess monitor could be reading wrong, just not sure what is going on with it.
 
Will have to look at those pulleys to make sure that is not the problem, I guess monitor could be reading wrong.
 
You must log in or register to reply here.

Similar threads

M
48 B Water flowing directly into crankcase (>2 qts/min)
Replies
18
Views
932
cushman
C
W
John Deere 212 Riding Mower Kohler With A 12 hp K301 AQS
Replies
3
Views
606
T.R.K.
T
C
Basic Tuning of Carbureted Performance Engines
Replies
2
Views
860
CFS Carbs
C
M
New-to-me JD-A and JD-B Repair Tips
Replies
13
Views
846
Fixingfarmer
Fixingfarmer
V
new owner of a 620, will try to update this as we go.
2 3 4
Replies
61
Views
3K
valiant8086
V
Tractor Parts Tractor Manuals

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Copyright © 1997-2024 Yesterday's Tractor Co.

All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.

Yesterday's Tractors - Antique Tractor Headquarters
Website Accessibility Policy

Back
Top