typical small engine carb issues

[MELOC]

i would rather fix my collection of small engine carbs with a big hammer, but i need to get something running that will mow grass.

sooo...the troybilt, briggs powered, self-propelled mower runs when given gas directly to the intake, but won't pull gas. i gave it a few drops several times and it runs and starves out. i removed the bowl and cleared the "bad" gas. the plastic float seems to be free and not sticking. i assume there is varnish in the small ports, but here is the puzzler. once, to be sure the float was not sticking, i unscrewed the bottom nut on the bowl and drained out a little gas...plenty of gas. i then tried to start the beast and it fired over for about the same amount of time as if i had dumped a trickle into the intake. i had those results twice.

because i didn't feel like totally disassembling the fuel line and such, i didn't check to see if the unit had a filter in the bowl like i have seen on others. maybe there is snot on the filter?

i also ran the needle out and in (totally removed it once) and tried starting the beast with the needle in several positions. the theory was that maybe there was a bit of schmutz that would dislodge if i moved the needle. that had no real effect.

so what do i need to do to get this beast running? it is a simple carb. do i need to run some thin wire through the ports? check the filter if it has one?

example 2

i inherited another push mower. it is a tecumseh. simple carb with a float that sticks on occassion. i had that one totally off and cleaned everything i could see. it will run as long as you jimmy the primer button, but it starves when left alone. it ran for an hour or two this spring, but it starves now.

any pointers?

[Ed Norman]

I always recommend Seafoam because it works. Last year I got a Honda cycle running that had been sitting for over 10 years with rusty thick gas in it. I drained the tank, put in a quart of fresh gas, and plenty of Seafoam. It took a while to make it's way thru the carb while cranking, then started hitting. Soon I had it popping and making smoke. It would die if I eased off the gas but finally it started almost idling. I rode it around the yard for a half hour at half throttle and it kept running better. I then added more gas and less Seafoam and ran it some more and now it starts, runs and idles like new. No teardown of the carb or anything.

I have done the same thing with many small engines. Once in a while it won't work because of an obvious problem, like the 1956 Evinrude motor with a dissolved float. But most engines that just got shut off and set aside respond very well to it.

It is in the parts store by the carb cleaners.

[Wis Bang]

Last time I used Dad's TB pony tiller I had cleaned the float & needle and had it running but the bowl was leaking so my neighbor took me to a local mower shop where he knew the owner. He cut me a new bowl gasket and inspected the carb. He had a squeeze bottle of 2 cycle fuel w/ a short hose. After filling the bowl he sat the bottle down and took an air chuck and blew in from the choke side while setting the mixture. You could actuall see the mix change. great way to set the carb and test it's function. Tiller started on the first pull when I re-installed it.

Sea Foam is even in the auto section of alot of wal-marts too. It's good stuff.

[Cabin Fever]

I've had carb problems on several small engines and fixed them all the same way....not saying this will work for you, but it has always for me.

I simply remove the carb. Take it completely apart. Soak the parts in carb cleaner. Spray the carb cleaner through every opening, jet, and orifice I can see. Then, put the sparkling clean carb back together and mount in on the engine. The enigne starts and runs flawlessly.

I've done this at least a half dozen times on different carbs. I have no idea what the orginal problem was. All I know is that I fixed the problem with a good, thorough cleaning.

BTW, the original problem was never old gas. I always drain gas between seasons and run the engine dry.

[MELOC]

i have heard that the use of ethanol in the gas blend is what is damaging our small engines, but who knows?

i bought some sea foam and gum out carb cleaner this evening. good grief...the sea foam was $8.67! i hope it works because now i won't be able to eat lunch for 2 days.

[HermitJohn]

What CF said, soak carb in carb cleaner and blow out the passages with can pressurized carb cleaner or compressed air. Actually most of time one $1.50 can pressurized carb cleaner is fine all by itself but with difficult carb, soaking overnight in big can carb cleaner is better. In my experience if needle valve is sticking or hanging you need to replace it which means buying a kit. Some of them just get weird and stick. Even back when the needle was all brass and didnt have the rubber tip, I still could never clean or hone needle to where it didnt stick occasionally once it started doing that.

I hope your seafoam experiment works, but I am not a believer in a "miracle in a can". I've lived through various popular "miracle in can" cures that came and went. Didnt see where any of them were worth the money.

[scott]

Marvel mystery oil is your friend.

it will clean out all the nooks and crannys

[Ed Norman]

Originally Posted by HermitJohn

I hope your seafoam experiment works, but I am not a believer in a "miracle in a can". I've lived through various popular "miracle in can" cures that came and went. Didnt see where any of them were worth the money.

Miracles in cans promise everything and don't deliver. Seafoam works as advertised.

Of course it won't fix a bent needle valve or cracked float, but it is excellent at cleaning out the gunk.

[HermitJohn]

Originally Posted by Ed Norman

Miracles in cans promise everything and don't deliver. Seafoam works as advertised.

Umm.... Seafoam instructions include putting it in crankcase, putting it in gastank, and putting it down the carburetor. If that isnt the mark of a "miracle cure all" then I dont know what is. Real products are sold for a specific purpose with specific expected results, not just some generic "better performance". If Seafoam for instance sold itself as a carbon cleaner that you soak say EGR valves in then I would have some respect for it. A pint of anything added to 20 gallon gas isnt going to do all that much. Same with it added to 5qt crankcase oil. Matter of fact diluting crankcase oil with a non-lubricant is never good idea. Even adding qt ATF to crankcase which may have some benefits short term probably not great idea long term. And ATF is an excellent lubricant with lot detergents.

[MELOC]

the briggs is running after a bit of carb cleaner, but i am missing (have been the whole time) a spring that regulates the choke. i would, and have tried) to make one work, but i have no idea how or to what it attaches. a lever operated by the throttle cable moves the choke to a certain point and then the choke is regulated by the missing spring. without the spring, the choke opens and closes as it chooses at the high setting just before it would be forced closed by the lever. back the throttle off of the start setting, and you have no regulation. i need a diagram for that one.

the tecumseh needs a new (tiny) spring that operates the needle in the float assembly (looks like a paper clip...kinda). it's odd though as the needle must have been sticking shut. the spring was corroded and barely held together. it fell apart when i was checking it out. it's hard to believe it had the fortitude to hold the needle up and closed. float itself doesn't seem to be sticking any. maybe if i reassemble the bowl, it will get the gas it needs...before it floods out, lol. i may as well wait until i can get to a shop to get parts to rebuild it.

[Ed Norman]

Originally Posted by HermitJohn

Umm.... Seafoam instructions include putting it in crankcase, putting it in gastank, and putting it down the carburetor. If that isnt the mark of a "miracle cure all" then I dont know what is. Real products are sold for a specific purpose with specific expected results, not just some generic "better performance". If Seafoam for instance sold itself as a carbon cleaner that you soak say EGR valves in then I would have some respect for it. A pint of anything added to 20 gallon gas isnt going to do all that much. Same with it added to 5qt crankcase oil. Matter of fact diluting crankcase oil with a non-lubricant is never good idea. Even adding qt ATF to crankcase which may have some benefits short term probably not great idea long term. And ATF is an excellent lubricant with lot detergents.

You talk like a person who has never tried it. I said to use it to get the carb ungunked. I never mentioned gas tank or crankcase. Look on some of the outboard motor rebuilding sites, or the golf cart repair sites, seafoam is praised by everyone who has tried it.

Every product tries to expand their market. Look at WD40. Supposedly does everything, except it only does a few things good. The rest are possible uses to get more sales. Business is built upon sales. You think the makers of Silly String started the company as a way to detect trip wires on booby traps in Iraq? But do you also think they complained when it started getting used for that and sales increased? Unless you have tried Seafoam and had a failure, don't run it down and talk without solid footing.

[HermitJohn]

Originally Posted by Ed Norman

You talk like a person who has never tried it. I said to use it to get the carb ungunked. I never mentioned gas tank or crankcase. Look on some of the outboard motor rebuilding sites, or the golf cart repair sites, seafoam is praised by everyone who has tried it.

Every product tries to expand their market. Look at WD40. Supposedly does everything, except it only does a few things good. The rest are possible uses to get more sales. Business is built uponI sales. You think the makers of Silly String started the company as a way to detect trip wires on booby traps in Iraq? But do you also think they complained when it started getting used for that and sales increased? Unless you have tried Seafoam and had a failure, don't run it down and talk without solid footing.

The only thing WD40 is really good for is to disperse moisture, like spraying under distributor cap on old engines in moist environment. Its not a good lubricant and its not good as penetrating oil to free up rusted parts. I dont use it and dont keep it around. A small old fashion oil can with some ATF or some light machine oil is much more effective lubricant.

Why would I buy Seafoam? Regular carb cleaner is $1.50 for a aerosol can (79cents before the big inflation last year) and works fine to clean up a carburetor. Why would I spend $8.50 for something that doesnt even advertise itself as a carburetor cleaner. Even according to you the Seafoam marketing is entirely build around getting people to buy it and waste it adding to gas tank and to crankcase, then buy more in hopes of some unspecified good result. I've never bought it, but was trying to help neighbor with his car, and he whips this can of Seafoam out and asks me what I think. Read label and tell him it sounds like a miracle in a can type product that implies it will do everything yet actually promises nothing. He puts half in crankcase and half in gas tank. And as promised... nothing. I've heard others that it will remove carbon deposits if you soak say egr in it undiluted, but it doesnt promise to do that so no idea if it does or not. I dont own a vehicle that still has an egr valve..... so guess I will never know.

[HermitJohn]

Originally Posted by MELOC

the tecumseh needs a new (tiny) spring that operates the needle in the float assembly (looks like a paper clip...kinda). it's odd though as the needle must have been sticking shut. the spring was corroded and barely held together. it fell apart when i was checking it out. it's hard to believe it had the fortitude to hold the needle up and closed. float itself doesn't seem to be sticking any. maybe if i reassemble the bowl, it will get the gas it needs...before it floods out, lol. i may as well wait until i can get to a shop to get parts to rebuild it.

Not a spring, just a clip to loosely connect needle to float arm, so when float sinks, it pulls needle down to let more fuel into the bowl. This clip is to prevent needle from sticking closed. Ideally gravity alone would cause the needle to fall as float lowers. You can make new clip out of piece of wire if necessary.

[HermitJohn]

Originally Posted by MELOC

the briggs is running after a bit of carb cleaner, but i am missing (have been the whole time) a spring that regulates the choke. i would, and have tried) to make one work, but i have no idea how or to what it attaches. a lever operated by the throttle cable moves the choke to a certain point and then the choke is regulated by the missing spring. without the spring, the choke opens and closes as it chooses at the high setting just before it would be forced closed by the lever. back the throttle off of the start setting, and you have no regulation. i need a diagram for that one.

Which Briggs engine do you have? Times have changed a lot in last decade or so. If this is old Briggs 3 or 3.5hp with metal carb and vane type governor then:

[MELOC]

no, that's not the one. i need to get the model number and maybe take a picture ...if my old sony mavica battery will hold a charge.

the air filter bolts on sideways and when you remove the plate, you see the air intake. on top and behind that is a plastic nut/accuator that has a "cove" on the side that a lever moves and it also has a tiny slot and hole for the spring to snap in.

i'll try to get some info and post it and maybe look it up. i got this unit for $30 used. it ran pretty well at first, but i think maybe the spring broke off before i ever looked at the carb. it started acting up out of the blue one day.

[MELOC]

pics of the carb...

[HermitJohn]

Not easy to find clear pic of this. Below is best I could find via google. I have a horizontal shaft Briggs engine on my ancient yazoo that has this choke setup. Dont know if I can get a decent pic without disassembling it or not. Anyway this is still a float carb with a choke plate. Engine once started and warmed needs choke completely open, so for temporary use you could tie it open with string or wire or whatever once its started and warmed up. Could also bend that metal tab that opens/closes choke out of way and just run a separate choke control cable down to the choke and independently control it separate from the throttle cable. Or you could leave things as they are and rig your own light spring to hold choke in open position. The throttle cable would force choke closed when in start position against the resistance of the spring.

I am going to be busy today but try to take look at my mower and see if I can take a pic that would do you any good without going to lot of hassle disassembling things. Sure this spring would not cost much, but you would need to go to mower shop and they might have to order it.

I have fought with this choke on my mower for some time as dang choke will close if you set throttle position too high but if you bend that metal tang enough that moves the choke to allow higher throttle setting, then the choke wont close when you are trying to start engine cold. Always searching for that happy compromise. But it hasnt annoyed me enough to re-engineer the dang thing with an independent manual choke cable though I have been tempted couple times and would have if I would have had spare cable handy.

[MELOC]

i tried to fashion a spring with stuff i had on-hand. i had a heavier spring, but couldn't figure where to mount the end that doesn't attach to the choke. i'll take a fresh look at it.

thanks for the picture.

[HermitJohn]

If you are going to use a non original spring, you want to fashion it so it holds choke open by default. Then check if when you have throttle cable in start position if the metal tang thing is holding choke closed.

I really think the answer on these chokes is to make the choke independent of the throttle cable like on old engines. Use original throttle cable as it exists, but then run a second choke cable and just forget the springs. Disable the metal thingy that lets throttle cable open and close the choke. You want choke to open/close completely independent of throttle position.

Saying that I do have my mower running pretty good with original setup, just cant max out governed rpms for heavy/tall grass as it will close the choke and flood the engine.

My old yazoo isnt set up for grass catcher. Just recently I put a verticle shaft Honda engine I had picked up very cheap on an old mower that I do have grass catcher for. Wanted the clippings for the garden. Anyway Hondas are just so much less frustration than any American engine I have dealt with. That Honda starts two pulls, no matter what. And it has a manual choke lever on the engine, no cables or goofy automatic choke setups. The Briggs has lot life left in it and I am Mr. Super Thrifty or I would swap it out for a Honda or Honda clone. Saving myself hassle and frustration has value too.

[MELOC]

one of the problems with rigging this with another dpring is that my choke sits at 90 degrees from the picture you posted and nothing i hook to will work. if i hook it to the lever/bracket in the far left, the square air fliter mounting plate obstructs the spring. there is nothing fixed i can hook it to. anything else, the throttle assemble, etc. seems to open the choke with spring tension as it is pulling in the opposite direction.

i went to the mower shop today and found a choke return spring...the only one they had, but listed for this mower. if i can figure how to mount it, i should be in business. i'll report my results, lol.