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Farmall & IHC Tractors Discussion Forum

Ih 666 tractor not running properly

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Author  [Modern View]

07-26-2020 12:30:23

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Good day
First off I am completely new to tractor repair with that said I have a friend with an case iH gas 666 that we've be trying to get running right so for new complete carb kit installed new plugs , wires, cap , rotor ,points, condenser , coil . Battery.
The issue .

Starts up great idles great revs up great slow as well as fast returns to idle great now all the tractor does is haying so sickle mower hay rake n Bailer so it doesn't work that hard however while using it it stumbles n pops when the tractor encounters increased drag ie, a small incline , turning a corner the tractor will act up till you throttle it down ti idle for a couple seconds then throttle back up with almost no issue
Question 1. Could this be and issue with the govner " I did notice while walking beside the tractor that the linkage rod going to the carb would "snap " rear ward and stay there till the throttle was moved to the idle position "
Question 2 where could I find adjustments or testing/diagnostic video/ procedures
Any help would be hugely appreciated
Pictures and videos are most preferred as I have a learning learning disability that makes it hard for me to read and understand
Thank you in advance

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used red mn

07-26-2020 22:52:49

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 Re: Ih 666 tractor not running properly in reply to Krazinite, 07-26-2020 12:30:23  
Okay the Tractor Vet has arrived in your post all well and fine. He has taken you down the road I was about to lead you of checking the timing. Even with all his ...laying down the law of the TV... he did not mention you should make sure your mechanical advance is working in your distributor. This can be done in sort of down and dirty fashion by pulling off the distributor cap bump the starter a little to see which way the rotor turns. Then taken the rotor between you thumb and forefinger and twist it in the direction it turns when running. Use similar force as you would to break the seal of a soda bottle. You should feel it turn against some spring resistance and when you relax it should return to nearly its original position. If it does this it is probably fine. It can be checked more thoroughly with a timing light but I do know the advance specs, maybe Tractor Vet will be willing to check his book for you in the morning and post back. Just to fulfill his prophecy, I will say I would take all his warnings about burning up the pistons etc. with a grain of salt. If you donít take this tractor out and pull it for about all she is good for 3 or 4 hours straight I believe it will treat you well on regular gas.

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The tractor vet

07-27-2020 09:25:36

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 Re: Ih 666 tractor not running properly in reply to used red mn, 07-26-2020 22:52:49  
Well as for the burning pistons i save one from the times that i had to replace them . (#1) the pistons are NOT the same as what they were when NEW as the org. pistons were Forged and the NEW pistons ya get are of a Cast design and will now conduct the heat as fast down into the skirts and into the cylinder walls as well so they retain the heat and keep getting hotter . Next todays reg gas burns way hotter , this is not something i came up with , this come from a chemical test lab that did a test on the gas when the first engine went down after a total rebuild . That engine had around 35 hours on it before it was put to work . This was on a 64 706 that when we rebuilt it we got the kit as per the owners request to up grade to a 291 from a C263 that had several different bore classes from the factory new , it had 2 A-B class bores and four C-D class bores so that meant ordering in two of one and four of the others as for you that think one size fits all NOT . It's not a big deal BUT you have to go to Your friendly Case I H dealer to get the sleeves to fit the hole and i am fine with this as the cost of parts does not come out of my pocket . If you use a A -B class sleeve in a C-D bore in short order you will find that sleeve in the bottom of the pan. The customer wanted a little more power and i told him ok fine so why not upgrade to the C291 kit for a C 263 since he insisted on all I H parts and hey he is payen for it . So we ordered in the KITS as that upgrade at the time was only avl. from Case I H . Now to do this upgrade you have to BORE the block and i sent the bloc off to the machinist who is way over the top on OCD , , first the block was checked for line BORE(not Line Hone) , Then the block was set up on his huge fancy Boring bar set up and the boring was done off the center line of the crank ( this operation will open your eyes as to just how far out center line of the pistons can be . ) each sleeve was Fitted to the hole down to the thenth of a thou. Each piston was fitted to each hole and here again the pistons are NOT all perfect and the same size , but fit the hole they were going into with .004 clearance ( that is half way between spec. ) the deck of the block required a dusting of around .006 thou. the head needed .009 . Now here is where we went overboard each piston was weighed along with the rod we took a avg. on bearings and rings then balance the crank , flywheel and dampener along with clutch and PPA , Cam was sent off for a rebuild . Carb gone thru and made into a C291 carb , Jet change and a few other tweaks , Dist was redone to C291 Spec. as they are different ( how many of you can redo a curve ) or have the equipment to do so. Around here i am last man standing that can do this. This engine was NOT a rebuild but a Build to get every oz of performance that could be pulled to work and not just a 300 foot pass . rockers were reground so there was no ware . when all done i spent a day running and fine tuneing and break in on the same gas i ran in my 706 RAG , yes my own 706 was a RAG/ DOG that no one wanted this is what i farmed with stuff i bought that ya got hug with , My rag/ DOG would run over 87 Hp impressive for a 706 gasser and would run all day and into the night dragging a 710 4x16 plow 8-10 inches deep up and down our humps and bumps . This one was doing that fresh . After eight hours run time at the shop on the dyno of varing loads and RPM's the customer took it home and used it to feed cows haul manure move bales ALL winter LONG . when spring came he called and said he now had 35 more hours on it and would like to get with plowing his 88 acres and was changing oil , told him i would be out shortly as i want to see how it was going to run . He and hooked to his set of 540 4x16's and went to the field . Made a couple rounds in fourth low and it was not even working it , we stepped it up to first high and she was hauling the mail only on some of the knobs when she got down in to the clay ya had to grab the T/A but pulling up hill she would just open the gov a little more . He had the gas from up the road from a little out in the country Maw and Paw place in it , the same gas i ran in my tractor and combine and pick up . He plowed all day on that tank of fuel . Fast forward to the next day Sunday. He came home from church and gets into his work closes and goes up and checks the tractor ove and fills the tank from HIS ON FARM tank that his fuel guy dropped off late Saturday afternoon , Then goes up to the long fields and start plowing he made the end turned around and was headed back when it started action up LIKE IT WAS RUNNING OUT OF FUEL , Missing throwing back smoke and JUST DIED and when he went to restart she was LOCKED UP . I get the call and he is doing a war dance , It is Sunday and SUNDAY is MY DAY , Told him to drop the plow right where it sat and fire it up and drive it to the shop and i would look at it the next day , And i get it's locked up told him it took you how long to walk from the tractor down to the house and call me and it will take you how long to walk back up to the tractor when you get back to it it will restart and may have a Knock now , don't worry about it the damage is done . Monday i get to the shop and it is setting inft. of the doors , I get it in and stuff it into a hole And pull the hoods and fuel tank drain the cooling system and pull the head , I figured one maybe two pistons were trashed NOT ALL SIX . All damage occurred ABOVE the top ring not at the skirts . So here is a news flash for you experts the top of the piston around the rings is .019to .020 SMALLER then the skirts are , so ya all that can add subtract should be able to figure this out . The PISTONS SWELLED more then .024 to LOCK up and score the sleeves . I have built many engines in my life time and can tell what caused damage and failures when everything was done correctly and what i saw was FUEL RELATED , He and i fought over this for a week while i was waiting on parts . His cousin convinced him that i knew what i was talking about and recommended what i was saying to have the gas tested . We called them and they told us to buy a new gas can and pump one gallon fron the fuel supply in question and DELIVER IT INPERSON to them . We never told them whos gas it was they told us and they told us that NO it was NOT the 93 that was ordered ( but he was Charged for 93 ) it was infact 87 and they told us what was in it and how it reacted when under LOAD and JUST HOW MUCH HOTTER 87 burns then 93 does . 87 is a super HOT fast burn in a flash where the 93 is a COOLER LONGER BURN . I am not feeding you guys a truck load of Horse manure that testing was NOT CHEAP by no means . And over the years when someone screwed up and brought a load of gas that was WRONG we knew it in vary short order as i was putting a piston or two in , Now MOST times if caught fast then you could squeak by with running the hone down the affected hole and cleaning th aluim. off the sleeve and run a bottle brush hone to dress it up add a set of rings and stuff it back together and CHANGE the gas . But even tryen to mow hay would cause them to get hot and seeze . Yea i loved the gasser , they were a great tractor for the hobby farmer , they were a great tractor for the small to med. Dairy farmer who needed a start in any weather tractor . This problem does not only affect the 706/806 gassers if it is a newer high speed 4cylinder or 6 cylinder the problem is across the board 87 does not even run well in the 460-560and they were made to run on 89 . Now you add in how many times that head has been milled down during a valve job when they find it is warped .007 on up . Yep your car or pick up runs fine , it is injected computer controlled it detects the sightest ping or knock and only runs about 25 to 50 % of full load . any of you ever watched the gov. on a tractor work tryen to hold perset RPM's under load . Just mowing hay with a 9 foot Haybine on first cutting on the hills to hold PTO Rpm's she was working at or close to wide open , even my 806 Diesel with the same Haybine will let you know just how hard she is working , the tone of the engine the teltale smoke trail and the fact that a Gasser RUNS way hotter then a diesel . How many of you youngsters ever spent and evening plowing , I am not talking about over loading i am just talking of working it in the normal work range , a gasser will make the exhaust manifold GLOW put the Cherry red glow to the muffler and might even stand 4-6 inches of FLAME out the top while holding work range RPMS not lugging it down to where you can count the fan blade. I do not have the answers on how to solve this problem now as going by the BOOK on everything Except running the correct gas has been covered Checked double checked You find the 93 octane gas set as per MFG spec.'s and they will do what they were designed to do with NO problem . Way back and i don't remember they year i was at my engine parts suppliers place and the one cute FOX that i delt with gave me the new parts books as mine were getting out dated and we are talking a stack of books that would rivell Any old parts store book rack but it covered ALL engines and all gskt. and engine related items . She like it when i called and gave her the numbers of what i needed so she kept me up to date on books . She kew that every once in a while i would build a go fast toy engine and i got the new TRW , clevite, and perfect circle books and while going thru then there was a section that dealt with Gas and engine building for the Street and just what one go do and not do . For what they call performace today on the street for the time 9.5 to 1 was max on 93 pump . ing timing was not to go over 36 degrees @ 2000 but rec. keeping it down under 34 and went into great lenghts on the CAST pistons over the FORGED pistons . Guys i have been working on engines for a lot of years from mild to wild engines some of you have never even seen . I have come up with ideas that even stumped a couple engineers that told that will never work and when it was lit off and did work all ya could see was there mouths moving and not a word came out .

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used red mn

07-26-2020 22:57:33

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 Re: Ih 666 tractor not running properly in reply to used red mn, 07-26-2020 22:52:49  
Oh and your question about the governor has not been answered. The governor is fine that is normal action and what it is supposed to do.

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The tractor vet

07-26-2020 19:29:40

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 Re: Ih 666 tractor not running properly in reply to Krazinite, 07-26-2020 12:30:23  
Yep I H gassers do not like the new gas . But here is what to check , Get a timing light on it and check ing timing at wide open throttle , I is late i have my Booties off and my books are in the truck so i am not totally sure on this for a 666 , But if it holds true being a C291 then ing timing should be 18 Degrees BTDC Next off you MUST run 93 octane gas . Yep there will be a bunch of know it alls tellen ya i don't know what i am talking about . When they have worked on them for 35 years and have fought the same problems with gasser like i have and you set down and READ and org. owners manual where it tells you that minimum octane requirement is 93 and back when that tractor was built 93 was bargain basement gas and regular gas at the pump was 95 . Your not the only one with this problem . Myself and all my close friends ran gassers and we fought the same problems . As long as you can get 93 and keep it in tune and timing set at factory set and you run low ash oil in them they ran fine . Now the best coming down the pipe line is 90 and even with them spiken the gas with Al-KI-Hol and calling it 93 what you will end up with is burnt pistons and scored liners . Our last gasser died 4 years ago with two trashed pistons while mowing hay . So the best i can tell you is good luck.

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07-26-2020 17:49:58

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 Re: Ih 666 tractor not running properly in reply to Krazinite, 07-26-2020 12:30:23  
You mention it only happens during a hard pull. This is indicative of running lean. Next time it happens, pull the choke out a bit to see if it corrects. That will confirm a fuel issue. Also, take a look at the plugs. They may indicate a lean mixture as well.

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07-26-2020 16:57:01

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 Re: Ih 666 tractor not running properly in reply to Krazinite, 07-26-2020 12:30:23  
Ok yes this carb has the fuel shutoff solenoid the carb as also bin cleaned multiple times all jets and passages are clear there is no screen in the fuel inlet at the carb only up at the sediment bowl which has bin changed if memory is correct the flow rate from float bowl was / is on par
The only time this issue arises is when the tractor needs to climb a small incline or a sharp turn so any slight drag and I starts to bogg down which is the reason I inquired and the govner as I noticed that it seemed to jerk all the way back and seemed to stay there until throttle back

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used red mn

07-26-2020 15:36:05

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 Re: Ih 666 tractor not running properly in reply to Krazinite, 07-26-2020 12:30:23  
Krazi welcome to YT! I am not familiar with the 666 but we had a 656 on our farm back in the 70ís, which is basically the model prior. If your carburetor has an electric wire going to a solenoid ..no. 46 in link..about an inch in diameter and 1 and a half long I am pretty sure it does not have a main jet or load needle that has been referenced by other to adjust. The main jet fuel flow is preset. The solenoid is installed in the place it would normally be. The solenoid cuts fuel to the main jet to limit ...dieseling run on...when shutting off the engine. Does the tractor hold speed on inclines when on the road in 5th gear and full throttle? If it does not I am going to suggest that the fuel supply is restricted some way. I think those carbs have a plug in the bottom pull it out it will have an initial flow of what is in the float bowl, but after that it should continue to flow at least a pint in 3 minutes. The fitting where the fuel line connects to the carb ...no. 17... also has a screen in it that can plug. In original configuration the only other filter is a screen in the top of the sediment bowl under the fuel tank. There can also be crud and rust in the bottom of the fuel tank that can plug up the flow of fuel out of the tank. All the carb info I have given you is in reference to the IH built carb, which I believe is most common. You can tell if your tractor has an IH carb if the 4 bolts that hold the bottom of the carb on are 1/4Ē hex headed bolts a 7/16Ē wrench fits. Sorry, canít really take the time to find a video for you. Any video for a 460, 560, 656, 706 and 806 would likely apply to you situation, though some of those tractors may have an actual adjustable needle valve main jet.

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used red mn

07-26-2020 16:05:40

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 Re: Ih 666 tractor not running properly in reply to used red mn, 07-26-2020 15:36:05  
The link may not take you directly to the carb diagram I referenced, it is under D-29. I will add if the fuel flow is acceptable my next step would be to pull the bottom of the carb off. Pull out no. 31 clean out the passages with carb cleaner and compressed air.

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07-26-2020 15:29:05

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 Re: Ih 666 tractor not running properly in reply to Krazinite, 07-26-2020 12:30:23  
Quoting Removed, click Modern View to see

Load needle? Not sure what your calling the load needle

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David G

07-26-2020 14:22:40

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 Re: Ih 666 tractor not running properly in reply to Krazinite, 07-26-2020 12:30:23  
Agree, open up power valve 1/2 turn and see.

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07-26-2020 12:54:43

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 Re: Ih 666 tractor not running properly in reply to Krazinite, 07-26-2020 12:30:23  
With all you've done to this tractor, my guess is
the load needle in the carb needs to be opened a
small amount at a time until the engine responds
well under load.

I don't have any pics, as the closest I've been
to a 666 is my brothers 656.
One of the guys on here will have pics.

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