50hp two stroke runs in emergency "open" and not normal

Joined
Nov 25, 2008
Messages
9
I ave a 2005 50hp two stroke that just started running in emergency only and not in normal (seems fuel starved in normal). I have already cleaned all fuel lines, fuel filter, taken carbs apart and blew them out. Also changed primer bulb and fuel connecters. Thoughts?:(
 

deejaycee_2000

Captain
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Mar 28, 2006
Messages
3,447
Re: 50hp two stroke runs in emergency "open" and not normal

is it autolube? ..... have you inspected the reed valves?
 
Joined
Nov 25, 2008
Messages
9
Re: 50hp two stroke runs in emergency "open" and not normal

I am using Yamaha Lube. Have not inspected the reed valves. Can you walk me through it generaly?
Thanks
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
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20,066
Re: 50hp two stroke runs in emergency "open" and not normal

check your carbs again.
emergency mode is actually manual enrichment and would be used for a manual cold start or if the primer failed.
reed issues will normally show up as a spit back of fuel from the carb when the piston is on the down stroke.
you can inspect them with a flashlight once the carbs are off.
but running only with the emergency on indicates a restriction in the pilot fuel circuit.
 
Joined
Nov 25, 2008
Messages
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Re: 50hp two stroke runs in emergency "open" and not normal

Thanks. Understand the reed valves are the valves inside the cylinder once I take the carbs off?
 

rodbolt

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Sep 1, 2003
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20,066
Re: 50hp two stroke runs in emergency "open" and not normal

trust me, ya missed something in the carbs.
the reeds are screwed to the backside of the intake manifold which is bolted to the crankcase cover.
a quick check is to run it with the air box off and look, if you have a busted reed you will see a lot of fuel spit out of the carb.
did you physically remove the main jet,pilot fuel jet and the emulsion tube and carefully clean them?
also make sure the transfer passage between the main well and the pilot fuel orifice is clear.
dont forget the rubber pilot fuel jet plugs.
all your doing by going to emergency is forcing the system rich and bypassing the normal idle circuits.
 

Dunaruna

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May 2, 2003
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Re: 50hp two stroke runs in emergency "open" and not normal

Great information Rodbolt, thanks.
 
Joined
Nov 25, 2008
Messages
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Re: 50hp two stroke runs in emergency "open" and not normal

Runs great now! Thanks guys. Broke the carbs down again and dipped each one in carb cleaner for about a half hour then used the air compressor to dry them out. Started right up and idles smooth.
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: 50hp two stroke runs in emergency "open" and not normal

I must be psychic.
or maybe just done this too long.
add a good 10 micron fuel water seperator and pray.
here in our area this ethanol fuel is killing us,its disolving tanks,fuel lines and fuel level floats.
I hope to post some pictures of some of the stuff I have found and saved in the past 6 months.
good luck and remember,fuel pump maint is not an option either.
 
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