Hello.
I have a b+s 28d707 . Been sitting outside for a few years doing nothing. Tried to fire it up- fuel spat outside exhaust. Removed carb, cleaned float and looked to be ok. Fired up the engine. Ran great for 2 minutes. Then a mixture of oil and petrol came spouting in to the top of the air filter. Emptied oil out - was full of gas. How many problems might I have? Took the cover off and the valves look to be both open at one point. Is it beyond help??
#2
Scrubcadet10
Most likely the float needle stuck in the carb or just failed alltogether, since it meters the amount of fuel going into the bowl when it fails, it just empties from the tank out the air filter, into the combustion chamber and into the crankcase.
looking at the IPL this engine used a Nikki or Walbro carb.
the nikki uses a replaceable needle with a non replaceable seat, and the walbro offers two different brass seats, one for gravity fed and one for pump fed and a rubber tipped needle. https://www.partstree.com/models/28...o-nikki-carburetors-carburetor-gasket-sets-8/
Thanks for the replies. Yes, oil was fine before I started it. I've ordered a new carb. Took the covers off to look at the valves. One of the springs had slipped too the side on the keyhole. Next step is to lap the valves in. Should I replace piston rings at the same time in case it is passing? And how big a job is that?
Do does it matter that the valves are both open slightly at the same time. Tried to catch in video. CLICK HERE
#6
Scrubcadet10
to me it looks like like the compression relief on the cam might be bumping the exhaust to make for easier starting,But it goes away when running. That's my opinion,
I'm sure the more knowledgeable member will know.
