Small Engine Carb Adjustment

buddyb

I bought an old but well cared for Simplicity 6516 mower.It had set for probably a couple of years with ethanol gas in the tank and carb and would not run.The engine is a 16 hp Briggs 2 cylinder opposed flathead.I took out the plastic fuel tank and cleaned it and replaced the filter and all fuel lines.I disassembled the carb and cleaned it in a ultra sonic cleaner.The fuel pump is built on the carb on this engine,so I put a kit in the carb and fuel pump.The engine started and ran fine,but if it is cut off,and tried to restart it floods very easy.The main adjustment screw on the carb has no effect on how the engine runs.I assume the jets in the carb are still plugged even after the attempted cleaning. Any ideas?

GuvamintCheese

Unplug the jets.

steve45

You have to remove the jets and emulsion tubes from the carb and soak them till they are clean. A sevice manual will show you what is removable and what is not. Often you can find a youtube video of exactly what you are working on a save the money and time of getting a manual.

Smitty500mag

He said he put a carb kit in it and a carb kit comes with new jets so they shouldn't be clogged unless he just purchased new gaskets and no jets. You can clip a wire from a wire brush and rod the jets and then put them in a ultrasonic cleaner.

I was going to put a carb kit in my mower but a new carb was cheaper than the kit in fact it was cheaper than the carb cleaner liquid.

Junkballer

I've got that engine, be extra careful and not lose the very small brass spring that sits in the plastic body part of the housing on a stud behind the diaphram, the spring operates the little "U" shaped flap in the diaphram, there is a much larger spring that operates the larger part of the diaphram. You have 2 adjustments, idle speed control and the air mix which definetly has an effect on it running (screw the air in then back out 1/2 way to start then fine tune ) I've rebuilt mine 4 or 5 times in 25 yrs...easy [;)]

steve45

Carb kits rarely come with new jets. Most jets are removable and made of brass so they can be removed and cleaned. quote:Originally posted by Smitty500mag
He said he put a carb kit in it and a carb kit comes with new jets so they shouldn't be clogged unless he just purchased new gaskets and no jets. You can clip a wire from a wire brush and rod the jets and then put them in a ultrasonic cleaner.

I was going to put a carb kit in my mower but a new carb was cheaper than the kit in fact it was cheaper than the carb cleaner liquid.

wpageabc

Replace that puppy carb...

bpost

For all the hassle it is a LOT easier to just buy a new carb and run only ethanol free gas from now on.

mogley98

Don't shut it off


Don

quote:Originally posted by buddyb
I bought an old but well cared for Simplicity 6516 mower.It had set for probably a couple of years with ethanol gas in the tank and carb and would not run.The engine is a 16 hp Briggs 2 cylinder opposed flathead.I took out the plastic fuel tank and cleaned it and replaced the filter and all fuel lines.I disassembled the carb and cleaned it in a ultra sonic cleaner.The fuel pump is built on the carb on this engine,so I put a kit in the carb and fuel pump.The engine started and ran fine,but if it is cut off,and tried to restart it floods very easy.The main adjustment screw on the carb has no effect on how the engine runs.I assume the jets in the carb are still plugged even after the attempted cleaning. Any ideas?

Smitty500mag

quote:Originally posted by steve45
Carb kits rarely come with new jets.


Then you've never worked on small engines very much have you. I've never bought a carb kit for a lawn mower or a motorcycle that didn't come with new jets. Otherwise it's not a carb kit but rather a gasket kit.

grumpygy

Did you set the float. Or when all else fails add a shut off between tank and fuel pump.

remingtonoaks

To adjust the carburetor, screw your idol and air fuel mixture needles all the way in but don't screw them In tight, just where they barely seat. Then back both of them out 2 1/2 full rotations. Then you might have to find tune it maybe an eighth of a turn either way

NeoBlackdog

What grumpygy said. Check to make sure that the float and it's valve are operating correctly. If the settings are correct then check to make sure there are no holes in the float so it can fill with gas and not work properly.

steve45

Well Ive been a marine mechanic for 39 years and have worked on hundreds of carbs for marine engines both outboard and sterndrive. Not one carb kit EVER came with jets nor could you buy ANY kit that did. quote:Originally posted by Smitty500mag
quote:Originally posted by steve45
Carb kits rarely come with new jets.


Then you've never worked on small engines very much have you. I've never bought a carb kit for a lawn mower or a motorcycle that didn't come with new jets. Otherwise it's not a carb kit but rather a gasket kit.

Smitty500mag

quote:Originally posted by steve45
Not one carb kit EVER came with jets nor could you buy ANY kit that did.


WE're talking about law mower motors but boat motor carb kits come with jets also if you order an overhaul kit and not a gasket kit.

https://www.amazon.com/Briggs-Stratton-694056-Carburetor-Overhaul/dp/B0038U3IRG/ref=sr_1_2?ie=UTF8&qid=1493743847&sr=8-2&keywords=carburetor+kits+brigg+%26+stratton

https://www.amazon.com/Briggs-Stratton-Carburetor-Overhaul-Replaces/dp/B00NNZ9UWS/ref=sr_1_4?ie=UTF8&qid=1493743847&sr=8-4&keywords=carburetor+kits+brigg+%26+stratton

https://www.amazon.com/Briggs-Stratton-498260-Carburetor-Overhaul/dp/B0032R18MM/ref=sr_1_5?ie=UTF8&qid=1493743847&sr=8-5&keywords=carburetor+kits+brigg+%26+stratton


https://www.amazon.com/Briggs-Stratton-498260-Carburetor-Overhaul/dp/B0032R18MM/ref=sr_1_5?ie=UTF8&qid=1493743847&sr=8-5&keywords=carburetor+kits+brigg+%26+stratton

Most all carb kits for motorcycles come with jets also.

https://www.amazon.com/GOOFIT-Carburetor-Hammerhead-Water-cooled-Scooter/dp/B00Z0DQKUG/ref=sr_1_1?ie=UTF8&qid=1493744154&sr=8-1-spons&keywords=honda+carburetor+kits&psc=1

https://www.amazon.com/1991-2000-Honda-FourTrax-300-Complete-Carburetor/dp/B01LBSWDSQ/ref=sr_1_6?ie=UTF8&qid=1493744256&sr=8-6&keywords=honda+carburetor+kit

Outboard Motor carb kits come with jets also.

https://www.amazon.com/Sierra-International-18-7226-Carburetor-Outboard/dp/B000N9HY98/ref=sr_1_9?ie=UTF8&qid=1493744363&sr=8-9&keywords=boat+motor+carburetor+kit