Lawnmower problems

[morg_nz]

lol wasnt really sure where else to ask this so here will do since people know about engines.

I gave my lawnmower a bit of a service the other day - cleaned up the carbon crap out of the head and gave the valves a light grind. i put the mower back together and it starts amazingly easily and runs really well, for about 30 seconds then it splutters and dies. kind of like when you start a bike with the choke on and leave it, eventually it will stop. well with the lawnmower its like the choke isnt going off. i think i;ve put everyhting back the way i found it but im wondering if theres something on the carb that i might adjust to fix this?

its a masport with a tecumseh engine (looks like an exact copy of the briggs and stratton on my lawnmaster)

an advice would be much appreciated

[unstuck]

Did you play with the carb at all, sounds like it is not getting enough fuel.<_<

[morg_nz]

Did you play with the carb at all, sounds like it is not getting enough fuel.<_<

didnt play with it but did disconnect it from the engine to get at the valve springs so im not sure if i've got it hooked up the right way

[unstuck]

Probably a good idea to clean the carb, tank, fuel lines, and air filter and give it another try.:Punk:

[cheese]

Those engines have really weak cranks. I bent one!!

Sounds like your float and its running out of fuel. Also there is a governor thing on the carb to stop it over revving.

[hayd3n]

my guess is theirs crap in the carb its moved all round now that youve removed it, clean it out

[browny]

make sure you hav reconnected the govenor link back onto the flap

[Winston001]

I know less than you. :D Is the carb sucking air through a gasket? I have an old Masport (B&S) rotary which has the same problem as yours and this is the best I can guess so far. Cost me $20 so it's just for fun. Also check that governor.

[unstuck]

If the governer spring or linkage is faulty, the engine will run erraticly, the revs will increase and then die out then rev up again. Running for awhile and then just stopping completely sounds to me like starvation of either air or fuel.:Punk:

[Akzle]

when you say "a light grind" on the valves... just how light? did you bend em or stuff the seats? did you put em back in proper, torque-ing teh springs?

what does the plug look like? wet? ie. is it death by flooding?

do a carb break-down/clean up then try again.

is it the fourstoke, similar to um80?