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98 merc not start normaly

J

jknoah

Member
"Hello someone, I need help fo

"Hello someone, I need help for my small old merc 9.8 motor. The Problem is to start this motor, I always have to spray some mixed gas into the Carb. But once it starts, It idles and runs very well. I cleaned the Carb but no cure.Cylinder compression and sparks are OK and other fuel system seems fine then what's the problem? What or where should I check ?thanks"
 
Flap choke? Semi-normal in tho

Flap choke? Semi-normal in those years. There may be an air leak at the lower crank seal that won't help either.
 
"How can I check an air leak a

"How can I check an air leak at lower crank seal? While I just turn the flywheel, There is a hissing sound from the engine. Is that it?"
 
"OK, I know you mentioned that

"OK, I know you mentioned that spark is fine, but just a thought anyway... have you checked that the gap on your spark plugs is according to specs?

My 15hp went from starting on the 6th pull on average to starting on the 1st when I finally got around to checking the plug gap left by the previous owner. Amazing what half a millimetre of excess airspace in the wrong place will do..."
 
"No, definitely not a spark pr

"No, definitely not a spark problem I think.I installed new plugs anyway. After failed starting attempts(pulled the cord numerous time),I checked the plugs and plug holes but there was no sign of fuel existing ,then spit some mixed gas into the plug holes directly, and pull the cord, It starts right up in just one pull."
 
"That don't sound good. I

"That don't sound good. I would tend to agree with Bandit - crank seal is shot or the reeds (my second guess).

Unfortunately, you have to split the block to get at either.

It really does sound like you are losing your air/gas/oil mix in the lower crankcase. Either it's leaking out, or the reeds are chipped/broken and it's bleeding back into the crankcase, or they are gummed and it's not making it through to the intake port in the first place...."
 
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