IH 666 Carb...HELP!!!!!!

in-too-deep · Oct 27, 2015

Ok, folks, I'm at the end of my rope. Reman Marvel Schebler I bought when I rebuilt the engine 4 or 5 years ago. Always ran great. Lately now it's very hard to start and needs the choke to run and likes to surge. Just way too lean all the time. I have excellent fuel flow ALL the time. All the screens are clean. No vacuum in the tank. All the passages are nice and clean and no corrosion or anything ugly in the carb. I've had it apart 4 times now. Even tried adjusting the float level. I have played with both adjusting screws til I wear out the screwdriver and neither will help. As soon as I push the choke in some, it stutters and the throttle plate slams shut and it dies. Choke is working as it should. My friend has a 666 also, so I borrowed his carb and it ran great. No issues at all. So, I know it's not a vacuum leak or valves or something in the engine. I also got a new carb to manifold gasket. This is my cattle feeding tractor and I would really like to fix it. Should I soak it in Holy Water?

504 · Oct 27, 2015

Take a small file to the corners of the needle valve,they are all made in China. A little bit of varnish build up and they stick bad.

old · Oct 27, 2015

When you cleaned that carb did you run a wire or other such thing in ALL the passage ways?? If you do not you still have some thing on one or more of them that is causing the problems. Me I use a torch tip cleaner tool to poke out all the passage ways carb cleaner spray and air and do it 2 or 3 times. I also soak the carbs in carb cleaner for 24 or so hours before cleaning them.

VicS · Oct 27, 2015

I go with old. You need to soak it. Then squirt carb cleaner with the pipe adapter. Don't give up.

Steve@Advance · Oct 27, 2015

You say the throttle closes as it is dieing? That sounds like the governor linkage is connected backward. The throttle should open as the RPM decreases!

Try starting it up with the governor link disconnected from the carb, control it by hand, see if there is any difference.

If that doesn't make a difference, open it up, look at the main jet circuit. Those are simple carbs, the full throttle fuel is siphoned directly up the venuri tube. All fuel passes through the main jet, so if it won't even idle, there is a restriction or air leak in the main circuit.

in-too-deep · Oct 27, 2015

Sorry I wasn't very clear. If I open the choke too much, it dies and usually the throttle slams shut as it dies. Throttle works as it should otherwise.

cuby · Oct 27, 2015

Venturi tube in wrong. I fought one of these many yrs ago and found that I had installed it upside down after cleaning the carb.

in-too-deep · Oct 27, 2015

Yep, very simple, which is why I'm so dang frustrated. The only thing I can see, is someone over tightened the main jet housing in the bowl. The needle is ok, but the brass housing that it screws into is ever so slightly twisted. That's the only thing left I haven't tried.

in-too-deep · Oct 27, 2015

Hmmmmmmmmmmmmm. I will try that.

in-too-deep · Oct 27, 2015

Yep all clean.

old · Oct 27, 2015

That part being twisted some will not hurt a thing have a tractor that has one that way for well over a decade and it has been running just fine.
As for the throttle when it starts to die the gov should be opening it up to max since it is slowing down so something is not right

old · Oct 27, 2015

If truly clean then you have as I posted in another one the throttle plate working back wards or some such thing since as RPM goes down the gov should open up the throttle. This one reminds me of one I did years back and cloud never get right. Got a replacement carb and set the old one aside for a few years. I then needed a carb and figured I would mess with the old one. It had not had gas in it for years and kept in an old fridge so dry etc. Cleaned it up and put a kit in and worked just fine. Found you can bake a carb at low heat and some times get things you can not any other way

in-too-deep · Oct 27, 2015

Yep! You were exactly right. Some dummy (me) should pay more attention!

IH 666 Carb...HELP!!!!!!

in-too-deep

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504

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old

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VicS

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Steve@Advance

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in-too-deep

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cuby

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in-too-deep

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in-too-deep

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in-too-deep

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old

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