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1998 50 hp yamaha

F

flatheadcat78

New member
"Hey guys, A buddy of mine brought his yamaha 50 2stoke over to me for some help. Motor was very rough running, Idle was very poor. Anyways I cleaned the carbs(In Carb soak). He also wanted a new pump so we did that. Well all buttoned up I busted her off on the hose. Ran well for a few minutes, then started to load up.Bottom plug pretty wet. Little bit of checking, notice fuel pump vaccum port was wet with fuel.Put a new pump on it. Now it starts and runs ok, coughs and spits, idles down some and shuts off. Plugs are a little wet, not soaked. The motor seems ok above idle, it will acell like a raped ape! Just the idle. I have cleaned carbs like these hundreds of times, I know I might of miss something during the cleaning. But normally that would cause a lean condition not a rich idle. We are missing something I know, Spark is also strong. Any ideas?? This motor also has the CDI with the electronic advance. Could that be it? Thanks again for any help
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"Best I can say on temp is yes

"Best I can say on temp is yes. Block itself gets warm, water peeing from motor is warm also.
As far as idle mixture screws, they are at about 1.5 to 1.75 turns."
 
"you replace all gaskets right

"you replace all gaskets right?

every motor will run fine on land and in neutral in water

i bet, you never synced her right\

soaking a carb is "no bueno""
 
Negative on the sync. Any why

Negative on the sync. Any why is carb soak bad?It sure cleans them nice.
What is the procedure for syncin the carbs?
Thanks
 
"All the carby butterflys need

"All the carby butterflys need to be set the same, so you turn the idle screw away and adjust the linkages between carbies to ensure all butteryflys are closed because if one is open the engine will cough and splutter then wind the idle screw to achieve the correct idle speed"
 
"Ok I did that earlier, same p

"Ok I did that earlier, same problem, Idles for a while than slows down and spits and dies.
If I advance the timing arm on the cdi just a little she will run pretty nice. as soon as I put it back to the mark II she will slow down and die. Even if I idle it up a good bit it will do the same. Whats up??"
 
"Could the CDI be the problem

"Could the CDI be the problem or is advancing the timing just hiding the problem? I pulled the carbs again just to look at them again. Nice and clean. Did the sync on them, backed off the idle, losened the screws on the each carb. Made sure all where closed. The idled it back up. Crancked it back up and same problem. Idles good for about 2 or 3 min. them idles down and cuts off. If I move the timing arm up just a little it runs ok?? Any ideas, or am I missing something?? What about the fuel enrichment or choke solenoid? Thanks again everyone."
 
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