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Yamaha 2004 F50 pilot screw setting

guyblond

New member
I made the bad. Before I got the service manual, I pulled the carbs off the motor and dissembled them to get a head start on cleaning and rebuild. This included removing the pilot screws. I'm thinking that the manual will have instructions as to the initial settings for the screws along with procedure to adjust after the motor is running and warmed up. But the only instruction in the manual is to count the number on turns from seating (which I didn't do) and return them to those positions on reassembly. There is nothing in the manual about this adjustment, and I haven't been able to find anything on-line. I have two questions:

First, does anybody have any idea of where I should start when I reassemble the carbs? And is the finer adjustment similar to other motors where you just richen the mixture until you get the highest RPM and them maybe lean out a little bit?

Second, does anyone have any idea of what Yamaha does upon manufacturing. There must be some adjustment, or they would just publish the number turns to set the screws.

Thanks in advance for your impute.
 
You are right in that they are best set by finding the highest idle and backing off a bit. You may also need to put a set of vacuum gauges onto the intake manifold to balance them afterwards. I think mine were set about 3 half turns out from seated from memory, possibly one or two more, but that will get you in the right ball park.

Stuart
 
You are right in that they are best set by finding the highest idle and backing off a bit. You may also need to put a set of vacuum gauges onto the intake manifold to balance them afterwards. I think mine were set about 3 half turns out from seated from memory, possibly one or two more, but that will get you in the right ball park.

Stuart

Thanks Stuart, I went over to your youtube channel, took a look and subscribed.

Greg
 
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