I have a Briggs & Statton 158cc 550 series as a Guernsey.approx4 yo.starrs but will not keep going .OK when last used 3 weeks ago

SOURCE: I need the instruction manual for Yardman 550

I hope this helps. heres a website that has the manuals for yardman. lawnandgarden.manualsonline.com/manuals/mfg/yardman/yardman_lawn_mower_product_list.html

Curtis Sewell

• 7482 Answers
• Posted on Jun 01, 2011

SOURCE: 158cc 5.0 500 series Briggs

Hi mtedepew...

Sounds like you have dirt/debris in your carburetor jets or fuel passages.
Check/Clean/Replace your fuel filter if you have one.
Also make sure you are using fresh fuel...and oil mix if your using a two cycle mower or weedeater with the oil to the right mixture and not too much oil as it can cause hard starting.
If the mower/weedeater is over a year old, then I recommend that you buy and install a new carburetor repair kit,because the diaphragm will get hard and that will cause it to be hard to crank.
Sounds like you will need to clean the carburetor or replace your carburetor internal rubber parts like the diaphgram and O rings.
I recommend that you use a laquer thinner type cleaner to clean and dissolve the laquer build-up in the float and needle jet passages.
Be sure to remove all plastic and rubber parts before using the laquer thinner because it can dissolve the plastic parts and render them unuseable.
Be sure to use compressed air to blow out all the fuel and air passages.
Be careful when blowing out the passages, because there are sometimes small rubber type seats in the bottom of some of the passages.
Sometimes you can get by with priming the carburetor or using starting fluid and letting it run a few times like that and it will flush the gunk out of the jets,but most of the time you will need to rebuild the carburetor.
Keep in mind that the float for the carburetor must be level when you go to reassemble the carburetor or follow the instructions you get with the carburetor kit.
When you clean your carburetor and remove the jet screws, you will first need to lightly seat the jet screws.
But before you lightly seat the jet screws count the number of turns it takes to seat the jet screws from their original position.
Be sure to mark the turns down on a piece of paper.
That way when you put the jets back in, you know to lightly seat them first and then turn them back out to their orginal position before you started.
Once you have your carburetor rebuilt that should solve your problem.
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SOURCE: one year old bolens push mower, 550 series B&S

How is your compression? If it is low, your piston rings and/or the cylinder walls could be damaged and pulling oil up to the combustion chamber, which will burn oil and foul the plug. If you overfill the oil you could possibly get this also. When was the last time that you changed the oil and/or put oil in it? Do you currently have proper oil level?

SOURCE: how do i idle down the engine or govern down the engine on a briggs and stratton 550 series mower model 10T802

that engine uses a fin style governor remove the upper cover and see if there is a nest or something holding the fins movement

SOURCE: My yardman with 158cc 550 series briggs & stratton engine runs very erratically and I put a brand new spark plug with correct gap measured , I started it once it ran very erratic again and then I

replace the diaphram in the carb