Excessive fuel consumption

R

rpaull

Forum Newbie
I just rebuilt my 16.5 HP B & S 28W707-0121E1 motor and it is hard starting (need to take the air filter off to get to start). I'm thinking it might be the rocker arm gap which both are set to .006. When it is running, it has a loss of hp and there is blowback through the carburetor which is most likely the reason it goes through the gas. Any help is appreciated!
 
If it runs only with the air filter off, or taking the filter off makes it run any different, then you need a new filter. Even if it looks clean, maybe it is oil soaked, and resistant to air flow.
 
I did replace the filter as the first step thinking the same thing, but unfortunately it did not make a difference.
I appreciate your reply!
 
If the intake is set at .006 clearance, why would I get blowback through the carb? One would think the valve would be seating not allowing the blowback??
 
rpaull said:
If the intake is set at .006 clearance, why would I get blowback through the carb? One would think the valve would be seating not allowing the blowback??
Click to expand...
Also, what reference should I be using while setting the rocker arm clearance?
 
The valve will be opening and closing at the wrong time. It will also not be opening wide enough.
Set the valve lash at 1/4 turn past TDC on the compression stroke.
 
I wonder if you don't have a fuel problem, to where it is running way to rich. It's not quite as likely if you have the Walbro carburetor, but if it has the Nikki, those things are kinda picky what with the fancy o-ring setup.
 
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