Intake Valve Build Up

[MaineDad 85]

Guys,

I took the carb off my C-160 because I have a brand new one being delivered tomorrow. I took a look inside and noticed some carbon buildup. Should I even try to remove some of it through the carb hole with a long cotton swab or something else? Or do I risk having some of that crud falling into the engine?

I know I could take the head off and access it that way, but I'd rather not at this time. What do you guys think?

[MaineDad 85]

Doing some more research, I may want to install new valves. If I buy a valve spring compressor and new valves, is it too hard of a project? Of course I would need a new head gasket too.

[KyBlue 655]

I wish I could offer some insight into ur question...but Im like you, gonna be waiting to hear what the experts say..

[Electro12WH 50]

I would wonder why there is carbon on the carb side of the intake.

[Electro12WH 50]

If you are going to install new valves, you need to recut the valve seats and lap them in also.

Someone asked (and I forgot who) about using water to decarbon. When I was a kid a century ago, we would pour water down the carb while the engine was running. Not so much as to stall it. Just a little at a time. The water turns to steam. Then when reving up the engine, chunks of carbon were blown out the exhaust.

By the way, what are you going to do with your old carb?

[MaineDad 85]

I'll probably just box the old carb up and put it away. Unless someone wants to buy it from me.

[KyBlue 655]

Whyd you replace it?

[bluetuna08 0]

ok...here goes...I am not trying to offend anyone...but...thank God the old days are over

please dont pour water down the carb because that would be bad in so many ways. the carbon build you see may be a "gum" from the gas or you valves are bad and blow by burning a little gas before it goes into the cylinder.

replacing valves is not hard if you know what you are doing

if you get new valves it is good to get a machinist to cut in new valve seats. if you run the tractor all the time it might be worth sprucing up the c-160. if you only using it occasionally than I personally wouldnt go through the trouble

buy a can of carb cleaner rather than sticking a cotton swab down in the hole. the carb cleaner will probably dissolve most of the build up anyway. although doing that isnt very good for the valve seats either but its what I would try first.

hope this helps.

[MaineDad 85]

Because it was obvious that it was in need of a rebuild. I took it off to inspect it and discovered the float was sticking, the float needle and seat were all gummed up, the bowl was all tarnished, the high speed needle was dirty and scoured, and the throttle bushing was worn. I looked into rebuilding it but found a brand new one at a great price.

[sorekiwi 761]

My take on this:

How big a can of worms do you want to get into? If there is carbon on the back of the intake valve, then it must be sucking oil up through the valve guide. Does the motor smoke?

Maybe the valve stem is worn, in which case a new valve (with an unworn stem) may fix this. Ideally you could cut a new seat at the same time, but you could probably get away with just lapping the new valve in.

Maybe the intaket guide is worn, so now you need a guide (they're cheap), and you definately need to cut a new seat, and possibly a valve as well..

And if youre doing the intake you might as well do the exhaust as well (which are more prone to giving problems anyway....

Unless you have a seat cutter (expensive), or know someone who will come to you to cut the seats, You'll have to pull the engine and take it to a machine shop. And then there's always the temptation to say "well, since I've gone this far, maybe I should..." and before you know it you've bored it, new piston etc etc and a $700 bill.

If the motor was running OK before (except for your carb issues), I would leave it alone. If you really want to get rid of the carbon, you could turn the engine until its at TDC on compression (both valves are firmly closed at this position) and scrape out whatever you can from the port. You'll need something like a little screw driver to "chip" off the carbon. Then you could blow out all the crap with compressed air. None of this will end up in the engine because the valves are closed.

I've heard about the water thing, but dont think I'd ever do it. The version I heard though, was to spray it in in a mist, like from an old Windex bottle.

Let us know what you decide!

BTW Micah, I read your website with interest. When I move to Ohio I want a place big enough for a reasonable size garden, so I'm trying to learn the ropes now. :hide:

[MaineDad 85]

Mike,

I agree. I'll first try to clean out what I can before installing the new carb. The engine does not smoke at all. I'm not ready, and neither is my wife, to open a $700 can of worms

Thanks for reading my web site. I have fun posting my experiences...

[big mike 13]

I wouldn't loose a minutes sleep over the carbon,no it's not normal but does not affect the running condition.If you replace a valve it should definately be the exhaust as the are much more prone to breakage from the extreeme heat the are subjected to.I have never seen a K series valve guide that needed replacement....the geometry of the valve train is very friendly to the guides.

Marvel Mystery oil may help with carbon build up.

Does the new carb have a high speed adjustment?If not you may want to hang on to your old carb.Without the high speed adjustment you are depending on the motor to run good at a setting determined by an engineer not having a clue as to the application the carb was going to be used in......my .02?....Walbro carbs SUCK!

If the throttle bushing is worn you may be able to find a machinist that would bore the hole and make you a new shaft.....works like a charm :hide:

[linen beige 14]

Is it carbon or just plain dirty build up? Shoot a little carb cleaner on it, it won't hurt the valves a bit. If it's just gummy,dirty build up the carb cleaner will take the bulk of it right out. If it is carbon you may be able to grind or just hand lap the old valves and give her more hours to live. If the seats don't have warpage or pits in them or a groove burned in them they don't need to be replaced. If the old valve is not chipped, warped, or burned down so thin that grinding, lapping will remove enough margin to allow it to close too far into the seat and stick, then a little elbow grease with some lapping compound might be all it takes. Even if that doesn't work, you have not hurt any parts that didn't already need to be replaced. Only spent a little time learning a new skill.

A fine mist of water into the intake of a running engine will soften carbon build up in the combustion chamber without hurting the engine. Water injection kits are still being sold, and they do work. But it won't have much, if any effect on any carbon in an intake (or exhaust) because there is no compression/combustion working to loosen it up.

[htopjimmy26 3]

Just curious , did you buy a new Walbro non adjustable carb? I would like to know after you get it installed how it runs. As to the carbon my 2cents aren't really worth the powder to blow 'em up but.......a little black soot/dirt/carbon is probably normal and nothing to worry about, Kohlers are dirty rugged little pigs that were engineered in the late 50's?, not formula 1 engines . If you can't chip a big hunk off then it's probably nothing to worry about. If you decide you must clean it out probably the thing to do would be pop the head off, then turn crank until the intake valve opens and hose her down with carbclean or ether[with carb off]. Good luck :hide:

[htopjimmy26 3]

BTW, if you smoke ingnore the ether part! :hide:

[MaineDad 85]

OK guys here's an update. I installed a new Kohler carb last night on the C-160. High speed it sounds much better, but I cannot get her to idle down now. I've made every possible adjustment on the idle speed screw and the idle mixture screw. She just sputters and smokes. Just a little throttle and she runs fine. I also noticed that gas is coming out of the carb after it is shut down now too.

I guess the head needs to come off huh?

Thoughts?

[sorekiwi 761]

OK guys here's an update. I installed a new Kohler carb last night on the C-160. High speed it sounds much better, but I cannot get her to idle down now. I've made every possible adjustment on the idle speed screw and the idle mixture screw. She just sputters and smokes. Just a little throttle and she runs fine. I also noticed that gas is coming out of the carb after it is shut down now too.

I guess the head needs to come off huh?

Thoughts?

I think you still have carb problems - even though its a new carb. Fuel shouldnt come out of the carb when you shut it down - the needle valve isnt shutting off the fuel.

I'd take off the bowl and check out the float/needle valve. Maybe before you pull the float off try and blow (with your mouth not an air gun!) through the fuel inlet. Gently raise the float and see if it shuts off the (air flow).

It is possible that a brand new (ie empty) carb can dislodge the needle valve or even go out of adjustment with regards to the float height. When the carb is full of fuel, the float is riding on a "cushion" of fuel. When the float bowl is empty the float can bounce around, unrestrained and the little tabs can bend a little. I've seen this before on automotive engines.

Flooding really shows up at low speed (high speed the engine can deal with the excess fuel). Was the smoke black (excess fuel) or grey (burning oil). And spluttering at low speed is classic carb/fuel problems. Valve problems would affect how it runs at high speed too.

Keep us posted....

[MaineDad 85]

Mike,

Thanks for the reply. It was black smoke. I'll take the bowl off and give it a look.

Thanks,

[linen beige 14]

I think you still have carb problems - even though its a new carb. Fuel shouldnt come out of the carb when you shut it down - the needle valve isnt shutting off the fuel.

I'd take off the bowl and check out the float/needle valve. Maybe before you pull the float off try and blow (with your mouth not an air gun!) through the fuel inlet. Gently raise the float and see if it shuts off the (air flow).

It is possible that a brand new (ie empty) carb can dislodge the needle valve or even go out of adjustment with regards to the float height. When the carb is full of fuel, the float is riding on a "cushion" of fuel. When the float bowl is empty the float can bounce around, unrestrained and the little tabs can bend a little. I've seen this before on automotive engines.

Flooding really shows up at low speed (high speed the engine can deal with the excess fuel). Was the smoke black (excess fuel) or grey (burning oil). And spluttering at low speed is classic carb/fuel problems. Valve problems would affect how it runs at high speed too.

Keep us posted....

My thoughts exactly! :D

[bambooheels 0]

needle valve isnt seeting right. thats one, who in the world ever thought h2O was good in any engine was on crck as for carbon on the intake side i doubt yu are seeing carbon more like sludge buildup from gas uildup. no big deal, is your head gasket good?

[linen beige 14]

who in the world ever thought h2O was good in any engine was on crck

Is that why the military used water injection in fighter aircraft and bombers up into WW II? Racing aircraft still use them. So do some racing boats. It cools the combustion chamber enough to allow higher compression/ more complete combustion/ higher power. It also eliminates cabon deposits. Ever notice that most all engines run just a touch smoother in foggy weather? The water mist being brought in through the intake just might have a little bit to do with that. No one has said to take a garden hose and spray it full blast down the carb (Although I have a '66 Ford Fairlane with a 289 2v that will run that way.). A FINE mist of water introduced into the intake will soften carbon in the cylinder and allow the compression/combustion to drive it out the exhaust.

[bambooheels 0]

sorry my friend but i know of much better ways to keep my engine clean, keep carbon to a minimum and keep water out of my engine. FYI the militry also dumps tons of jet ful and unused fuel into the oceans every day, that doesnt meen they are knowledgale people. think we all can agree that kohler, tecumseh, briggs and in your case ford would never recommend using water for any internal reasons in air cooled engines, and no i never seen any serious differnce when it was misty out, maybe we should call NASCAR and tell them only to race on misty days! any smart, reliable, self respected good small engine mechanic would find other ways to clean carbon buildup. but if you want to do it that way, lets all have a bi annual feed your engine water day so everyone will have a good running engine...

by the way if i sound alittle disturbed its because i am, am be real my friend you cannot compare what people do to V-8 engines to a small air cooled engine, i can run diesel in my truck but i woudnt put it in my wheel horse..... :imstupid: