hey,
bought my mom a sears/briggs mower about 1-2 yrs ago.
most poorly designed POS mower. (who puts the spark plug up front?? now it shorts out everytime she mows under a bush.)
It runs, but is always reving up and down, up and down. constantly.
I am going to change the oil out, because its black, and so was the plug which i cleaned,
but there is NO carb adjsutment on mowers anymore? no a single screw??
the muffler is also black, would that effect it running smooth?
besides a good clean out, anythign else I should look for / do?
Most of the newer mowers just need the carb. disassembled and cleaned out every couple years especially if she didn’t put stabilizer in at the end of the season. My 4 year old MTD mower is notorious about this. Also check for water in the gas tank and a dirty air filter, black muffler indicates a rich condition which could be air filter.
there may be a spring loaded lever as part of the carb is stuck or whatever .lever moves & little spring controls itas engine runs. this may have to do with sporadic revving. i have older lawn mowers.
no, and oil can not get any darker. thats what i’m doing next.
The filter i bang out constantly for her. always dirty
Does STABLE go bad? i think the can she used was real real old but that stuff never goes bad i thought.
yes, that spring is all the carb relies on… oddly. you can see it flexing as the mower revs up and down, not hung up.... but now that i think of it, it is not
the perfect condition spiral that it was when new… perhaps i should look to replace that too, thank you
probably jsut needs a carb removal and total cleaning, just that its less then 2 yrs old, and i didnt want to do a total teardown....i’m bound to
bust something in removal .....its just me
Is Briggs still using the old diaphragm/gasket on their vertical shaft engines? They used to deteriorate every other year or so. My mower guy used to order them by the case…
nope, no carb adjust that i can find......
and the fuel should have been fine, my mom has some dry/dust areas and the mower seems to be always dirty.. its probably dirty/clogged somewhere.
guess i am gonna pull it apart.
not sure about the gasket… gotta look at the book again.
Clean the carb and remove tank and clean and check your gas can for residue. Wouldn’t hurt to keep your gas can out of the sun, this can cause condensation. Add isopropyl to gas can every fillup to take care of any moisture.
Pinch the fuel line or drain the gas out. Take the bottom plug out of the bowl on the carb. Watch so you don’t tear or stretch the square o-ring around the perimeter of the bowl. When the plug is removed the bowl may or may not fall with it. The main plug -think its 1/2"- has a sleeve on it that has a main jet in it and a little hole on the side that lets gas into the main jet. My bet is that hole or the main has some green varnish in it not to mention the whole bottom of the bowl. Carb cleaner doesn’t work on this kind of varnish. The only way to really clean a varnished up carb is to take it off, disassemble it and soak it in Simple Green that stuff is the best thing that I’ve found for cleaning carbs. These new motors have no carb adjustment other that idle speed.
Pinch the fuel line or drain the gas out. Take the bottom plug out of the bowl on the carb. Watch so you don’t tear or stretch the square o-ring around the perimeter of the bowl. When the plug is removed the bowl may or may not fall with it. The main plug -think its 1/2"- has a sleeve on it that has a main jet in it and a little hole on the side that lets gas into the main jet. My bet is that hole or the main has some green varnish in it not to mention the whole bottom of the bowl. Carb cleaner doesn’t work on this kind of varnish. The only way to really clean a varnished up carb is to take it off, disassemble it and soak it in Simple Green that stuff is the best thing that I’ve found for cleaning carbs. These new motors have no carb adjustment other that idle speed.
thank you for this bit of info.i have a push mower that was on its way to the scrap yard because it wont run and it looks like new...now i will tear it apart and check this out. fyi, sea foam does an awesome job on carbs as well
Get a product called sea foam at your farm and fleet or tractor stores...maybe even a boat store. Dump ALL the gas and get fresh with the sea foam. Start it and go about your mowing...by the next time you mow it will have cleaned the carb out. There is no adjustment on them, they are throw aways...sad to say a good pushmower nowadays is a toro or honda and they are 450.00 plus.
