I recently bought a 2004 50TLRC for my flats boat. I've owned 12 Yami's over the years, but this is the smallest HP I've had. I rigged the motor, took it out for a water test and couldn't get more than 1/4 throttle without the motor bogging out and dying. Started and idled fine, but would die past 1/4 throttle. Took the cowl off and noticed the emergency enrichment lever was set to on. Moved lever to normal- problem solved. My question is what is the purpose of the emergency enrichment lever- and why is it only on the smaller HP motors?
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Emergency enrichment lever
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It's a fully automatic "Prime Start" fuel mixture enrichening device used on carbed motors. The "normal' is the automatic setting, the "on/off" is to activate it if it's somehow disabled...it's solenoid is electrically actuated. My Yamaha is a 1999 and I've never had a problem with the Prime Start and I have the impression they're pretty trouble-free. Of course the newer Fuel Injected motors wouldn't use a Prime Start. Good Luck!
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Prime start system enriches the fuel to all cylinders at cold start.
Once running the motor charging system sends voltage to the heater unit and it warms up a wax pellet that pushes a needle into a seat to close off the passage.
the emergency on lever position is to help you start motor if there were starvation problems out on the water due to passage plugging
The owners manual says once motor is started and warmed up you should turn it to the off position and motor back to shore and have the motor fixed.
Robert runs the C90 , but have no idea if any higher HP motors have it or not
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Yes instead of a choke.
(CDI)advances the timing at start up until temp switch tells it the motor is warmed up, (If you lift the fast idle lever past a certain point, it then drops the advance)So leave lever in the down position when starting
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Originally posted by 99yam40 View PostPrime start system enriches the fuel to all cylinders at cold start.
Once running the motor charging system sends voltage to the heater unit and it warms up a wax pellet that pushes a needle into a seat to close off the passage.
the emergency on lever position is to help you start motor if there were starvation problems out on the water due to passage plugging
The owners manual says once motor is started and warmed up you should turn it to the off position and motor back to shore and have the motor fixed.
Robert runs the C90 , but have no idea if any higher HP motors have it or not
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If you follow the fuel hose from prime start enrichment system, it hits the manifold behind the carbs that is cross drilled to each cylinder intakes.
enriching one cylinder does not make for a very good running motor with the other cylinders running lean
I believe it was rodbolt that posted that to me once, but it could have been someone else
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Originally posted by 99yam40 View PostIf you follow the fuel hose from prime start enrichment system, it hits the manifold behind the carbs that is cross drilled to each cylinder intakes.
enriching one cylinder does not make for a very good running motor with the other cylinders running lean
I believe it was rodbolt that posted that to me once, but it could have been someone else
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pime start on the 3 cyl motors is fully automatic.
hitting the choke switch does nothing as its not connected to anything at the engine.
the prime start on the 3 cyl draws fuel from the middle bowl and utilizes a small pulse pump,pulses via #2 cyl, the pump fuel to the intake passages via a small gray line.
enrichment valve power is via the lighting coil on the stator assy.
as current flows when the engine is running the wax in the valve heats and the needle extends shutting down the enrichment.
the lever is in case the valve is stuck down,some models have normal,open and off.
open bypasses the enrichment valve, off closes ALL enrichment. that would be used if the lighting coil or valve wiring failed.
very simple system that like precision blend, kicks techs butt.
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