Hello
I've had a Briggs and Stratton 35 Classic 3.5 hp for about 8 years and its been great until recently. Its running rough chugging and a little blue smoke. I hit a tree root a few weeks ago and its been like this ever since? I've took the spark plug out and it was black and a little wet cleaned it and cleaned the air filter ran it for about 20 seconds it still ran rough checked the plug and it was black again. Its like its running rich or not getting the air fuel mixture right or even out of timing?
Diaphram sounds good to me, oiled up plug heavy fuel consumption blue smoke (chugging) diaphram deffo.
Alan B
July 2012
Probably the diaphragm in the carburretor- they need replacing every so often.
The Oracle
April 2009
Callum can you pls let us know how to change piston
jane
April 2009
I had a similar problem with my lawnmower (also 3.5hp B&S), which cleared itself up after using it for half an hour. What had happened was that the oil from the sump had gone into the carburettor or air filter, and was being fed in with the petrol. I'm betting you turned the machine over, or onto its side, to look at the damage.
In my case, I'd also put a bit too much oil into the sump, which didn't help.
Alvery
July 2008
I had a similar problem with my lawnmower (also 3.5hp B&S), which cleared itself up after using it for half an hour. What had happened was that the oil from the sump had gone into the carburettor or air filter, and was being fed in with the petrol. I'm betting you turned the machine over, or onto its side, to look at the damage.
In my case, I'd also put a bit too much oil into the sump, which didn't help.
Alvery
July 2008
sounds like you have damaged a seal or piston ring same hapend to me easy to fix if you no how...
CALLUM
June 2008
Automatic Answer
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