gap599
New member
Hello again everyone, I have created a couple of previous threads asking for help dialing in the jetting for the new motor in my sled (trail ported), and received lots of great help. I think i'm almost there now, just have a few more questions:
1) I switched from 42.5 pilots to 45s because it had an idle hang sometimes. The 45s cured the idle hang problem, but it is now harder to start (cold and hot). It's not that bad now (maybe 4-5 pulls average), but it was much better before (1-2 pulls). I'm just wondering if this is because its jetted on the rich side now?
2) What is the relationship between fuel screw adjustment and pilot size to fuel flow? i.e. with 42.5 pilots and screws 2 turns out, when i change to 45 pilots, how many turns out on the screws to have the same flow(0.5, 1?)? or do the different sizes not even overlap?
3) Does it matter where i buy jets from (pilots and mains)? I have an assorment of jets all bought from different places, and made by different companies i'm sure. I was under the assumption that a 150 is a 150 regardless who made it. My buddy is saying that I should only use OEM Yamaha jets becasue the aftermarket ones may not flow the same - is this true?
1) I switched from 42.5 pilots to 45s because it had an idle hang sometimes. The 45s cured the idle hang problem, but it is now harder to start (cold and hot). It's not that bad now (maybe 4-5 pulls average), but it was much better before (1-2 pulls). I'm just wondering if this is because its jetted on the rich side now?
2) What is the relationship between fuel screw adjustment and pilot size to fuel flow? i.e. with 42.5 pilots and screws 2 turns out, when i change to 45 pilots, how many turns out on the screws to have the same flow(0.5, 1?)? or do the different sizes not even overlap?
3) Does it matter where i buy jets from (pilots and mains)? I have an assorment of jets all bought from different places, and made by different companies i'm sure. I was under the assumption that a 150 is a 150 regardless who made it. My buddy is saying that I should only use OEM Yamaha jets becasue the aftermarket ones may not flow the same - is this true?
with 45 pilots you need the fuel screw at 1.5 out.
the further the screw is out the more (richer) it makes it on low speed, but only to the extent of the size of the pilot jet.
you can use aftermakrket jets as long as they are designed for the flatslide carbs and have the round heads.
the further the screw is out the more (richer) it makes it on low speed, but only to the extent of the size of the pilot jet.
you can use aftermakrket jets as long as they are designed for the flatslide carbs and have the round heads.