[lexmarks567]

I have a craftsman lawnmower had it fixed at the shop due to the fact it had a broken flywheel key so it was fireing on the up stroke ripping the rope out of my hand. Anyway $113 later it was working for awhile now its developed another problem. it surges up and down then dies. it speeds up slows down over and over then will stall. i wondering if they screwed something up. It started doing it after I was using it for a short while but got worse and worse .where do I start

[katonca]

Hi lex,
I'm not at all a mower mechanic, but have coaxed my little used jewels to work well beyond their life expectancy.

Have you made sure it's breathing ok with a clean filter, sprayed the area around the choke and springs with gumout, changed the plug?

[lexmarks567]

Originally Posted by katonca

Hi lex,
I'm not at all a mower mechanic, but have coaxed my little used jewels to work well beyond their life expectancy.

Have you made sure it's breathing ok with a clean filter, sprayed the area around the choke and springs with gumout, changed the plug?

they did all that at the shop. New filter new plug fresh oil

[Knotbored]

Look closely at the carb linkage as it sits with the throttle about half-way on (you have to figure a way to park the mower or let your wife sit in the seat.) You might have to remove the air filter to see anything. If you see the linkage move as the engine pulses then the problem is related to a little flap that acts like a governor that sences the air volume going past the intake. Try gripping the linkage (the one moving with no changes by driver) and see if the surging stops.
If it stops then maybe the mechanic bent that flap when installing the filter.
I have no advise on adjusting that flap-but I did just bent one once on a Brigs engine and managed to make surging stop.

[Knotbored]

Lex- I just realized this is at leaste the third thread you have related to gas engines several with almost identical problems.
I am now willing to bet all these problems relate to bad gasoline.
Note a gas can set in the sun expands and leaks out dry fumes, then cools at night absorbing moist night air which condenses. I am sure dumping the tanks of all those motors and filling with fresh gas -NOT THAT KRAP IN THAT OLD CAN! will resolve your problems, perhaps needing new gas filters (about a buck apiece.) You will have to pull the rope a few times to clear out the gas in the lines, bit I am about 99% positive you atre feeding those engines poison gas.

[lexmarks567]

Originally Posted by Knotbored

Look closely at the carb linkage as it sits with the throttle about half-way on (you have to figure a way to park the mower or let your wife sit in the seat.) You might have to remove the air filter to see anything. If you see the linkage move as the engine pulses then the problem is related to a little flap that acts like a governor that sences the air volume going past the intake. Try gripping the linkage (the one moving with no changes by driver) and see if the surging stops.
If it stops then maybe the mechanic bent that flap when installing the filter.
I have no advise on adjusting that flap-but I did just bent one once on a Brigs engine and managed to make surging stop.

1. its a push mower and 2 I don't have any other problems with my mowers. just this mower and my chainsaw. my other chainsaw works 100 % and so does my other 2 mowers. Im betting the repair shop did something to the mower. All my other gas powered stufff works fine

[lexmarks567]

Well I took it in to the shop it will be ready by the 23rd. Well let you know how much it is and what they fixed. Service required-MAINT-TUNE UP-THROTTLE RACING UP AND DOWN

[lexmarks567]

OK got it back about 3 weeks ago I had my dad use it while I was on vaction so the grass would get cut. I have 3 mowers. sense this one was supposed to be fixed I had him use this. He got the front done but it BROKE DOWN AGAIN. so when I got home got it started and it surged up and down. so I took it back to the shop he tried it and took the carb apart and TURNS OUT ITS A BAD O-RING AND MAIN JET. the O-ring was disintergrating clogging the jet. He said engines surge like that when they don't get enough fuel. Those 2-3 parts where never replaced when they rebuit the carb the first time. and this did not show up untill a few weeks of use after that first repair. The first repiar was a carb repair and a new flywheel key. Second repair was for the engine reving up and down. This time WE SOLVED IT I HOPE. its was a bad o-ring and main jet. now My dad being stupid could not get the other 2 to start so the back yard is about a foot high.but I had no problem