QuestionI re-did the carb and noticed that the first time I did not properly align the hole in the bowl nut. It will now run for a little longer (a minute max) but still die and smoke like crazy. Compression test gave me 53 lbs. I don't know the specs on the engine, but that seems kinda high - maybe my compression tester is broken. Also I just checked the oil, and it's not very viscous and smells a little like gas. What do you think?
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Followup To
Question -
Hi engine guru,
I'm resurrecting my mower from the dead after sitting for 7 years. It's a Murray w/ a 4.5 HP Briggs Quantam engine. I changed the plug, air filter, gas, fuel, and rebuilt the carb (yeah, it was nasty). PROBLEM: When I start it (primer button pushed 3-5 times), it will run rough for 10-45 seconds, then sputter out and die. Lots of white smoke billows out too. I'm at a loss - Any advice?
Answer -
Hi Shawn,
At first I would say that you missed some obstruction in the carb and that MAY be the case. Especially if you can keep it running by continuous priming. The smoke has me wondering about another problem. A sign of burning oil may indicate low compression from frozen piston rings or oil getting past worn valve guides.
Do a compression test and/or re-clean the carb.
Let me know how you make out.
Michael
AnswerHi Shawn,
53 lbs is low. 75 is minimum, 115-150 is new.
A gas smell in the oil my be from piston ring blow by.
You might need to disassemble the engine and check the rings and valves. Also check the carb again or replace it. You might be better replacing the engine or entire mower.
Good luck,
Michael
