# Briggs & stratton 17hp pumping out black smoke



## Apoxymoron

Type * 0122-E1
Code * 06090111
Model No.305777*

My lawn mower has been blowing out loads of thick black smoke. 
The plugs get really coked up. I've cleaned the carb and float chamber
Checked and cleaned the oil breather in the crank case
Changed the seals and it's still not running properly and still throws
Out loads of thick black smoke
Any ideas on the route of the problem and any solutions
Thanks


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## Basementgeek

Hi and welcome to TSF

You have a carb problem as it is running way to rich. Make sure the choke opens all the way.

If the choke appears to work OK, get a rebuild kit for the carb.

Be sure to check your oil. It may be over full because it contains gas.

BG


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## Apoxymoron

Thanks. 
The choke is working fine which is why i've been stumped as to whats wrong with it.
Ill try the rebuild kit.
The oil level is fine and not due a service for another 25hrs. would it be advisable to do an oil and filter change as well or is it not worth it?
Thanks for your help


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## MPR

Here are some troubleshooting steps. They work for my mowers.

How to Troubleshoot Briggs & Stratton Black Smoke | eHow.com


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## Apoxymoron

Its got brand new plugs in. (they just get coked up straight away so constantly been cleaning with good old carb cleaner) not been using it but when i run it to see if the problem is still there. 
I have adjusted the mixture (thats the little adjuster on top of the carb?) 
Have not tried a new air filter but cleaned the old one and blown it out with the airline. Its in good nick.
The mower is 4 years old but its not been used extensively.
unfortunatly the warranty ran out last year.


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## Basementgeek

Try running it with the air cleaner off for a few minutes and see if the black smoke goes away. If it does you need a new air filter.

Don't run it without air cleaner on and cut grass.
If oil is not over full and does not smell of gas no real need to change oil any sooner.

BG


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## Apoxymoron

Thanks, i've run it with the air filter off and still has the black smoke  the oil is gd with no smell of gas in it.
i'm going to give the carb kit ago and see if that makes a difference
Thanks


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## Tomken15

Try a bit of brake fluid down the carb and keep the revs up - used to be known as the poor man's decoke (and stand up wind of the exhaust :smile: )

Besides being coked up, what colour are the plugs after the engine has been running a while ?

Chocalately brown would indicate a good fuel/air mix, black and sooty - rich, unless there's oil trace deep down in the plug.

Given how lightly used it appears to have been, constantly coking up tends to point to the fuel being used.

With todays additives, coking up is generally a thing of the past.

Try getting your fuel from somewhere else.


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## Apoxymoron

Hi Tomken, 
I'll try the brake fluid way, although i have been using proper spray carb cleaner.

The plugs are Black and sooty and thats after i cleaned them and ran it for 2 mins standing still. The plugs are dry when i take them out so dont thinks there oil in the bottom.

I'm using Shell garage reg unleaded in it which i found to be the best in my car. i dont use supermarket fuel as it tends to be weaker. I'll try some Premium fuel like Vtec see if that makes a difference.


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## Tomken15

Other than adjusting the carb, I was wondering if the CB points were correctly adjusted to give the correct duration of spark, but black and sooty definitely points to a carburation problem.

The adjustment for the carb is to turn the screw in until it just gently seats and then unscrew 1.5 turns.


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## Basementgeek

They have not put points in B&S engine since about the middle of 1981.

BG


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## Tomken15

Basementgeek said:


> They have not put points in B&S engine since about the middle of 1981.
> 
> BG


Then it won't be those then :grin:


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