Pilot Screw adjustment 130hp

[Fishers20]

on a 1996 S130TXRU 130 Yamaha, is the pilot screw an air mixture setting (lean in, rich out)? Thanks

[rodbolt17]

there is NO rich or lean.
its more or less.
the ratio is controled by the pilot air and pilot fuel jets.

[Fishers20]

Is it a more or less at idle or at all speeds? Motor tends to have heat soak issue after sitting for longer than 20 minutes, trying to fine tune it.
Thanks

[200090tlry]

Ive been going over my motor

The pilot screws I started at 360 degrees plus 180. Didnt run for crap at lake not sure really why but I adjusted enrichment valve from closed to normal. Then went clockwise on pilot screws 90 degree's. Seemed to run without stalling. Im using degree's because not everyone knows what 1 1/2 turns out really is.

[axolotl98]

there is NO rich or lean.
its more or less.
the ratio is controled by the pilot air and pilot fuel jets.

Can u elaborate on this ?
If the pilot screw is in, ie. turned clockwise until it stops, what happens ? No air & no fuel in the cylinder ?
If it is unscrewed by 1 turn, then some air and some fuel goes into the cylinder. And if unscrewed by 2 turns, then double the air and double the fuel go in ?

If you want to have a slightly leaner air-fuel mixture high up in the rev scale, then can you adjust it using the pilot screw ?

[200090tlry]

He is correct

The jet has opening that will not change in size. Think screw only changes flow to jet or volume fuel. Curious what Rod would say is maximum you can turn these out or in from manuafcters specs? I mean they would not have the screws unless you can adjust them right? Mercurys they have you run motor go rich then go lean and find happy spot in middle as long runs clean and quick at high speed. Im curious as how pilot screw works on Yamahas I thought is was for low speed settings but doesnt make sense. You really wouldnt want a leaner condition running full rpms great way to kiss piston bye bye. Less fuel means much hotter burn in cyl. Yeah 2strokes do seem to run better lean but well you know. I was planning on replacing my jets for 5200 alititude but with yamaha im better off leaving it alone.

[Fishers20]

The pilot screws I started at 360 degrees plus 180. Didnt run for crap at lake not sure really why but I adjusted enrichment valve from closed to normal. Then went clockwise on pilot screws 90 degree's. Seemed to run without stalling. Im using degree's because not everyone knows what 1 1/2 turns out really is.

The book says 7/8 turn out +/- 1/4 turn. According to Boats.net turn in leans the mixture and out richens it. I may bump it out to 1 1/2 turns like you have done and see how it does. mine is set at 1 turn out presently (or 360 degrees).
Thanks for the input.

[99yam40]

If all passages and jets in the carbs are clean then the factory settings are where the motor is to run the best. They give a small +or- turn in the specs
If the motor is having a problem running with the carbs set according to the service manual specs then you need to clean them

[rodbolt17]

Ill reitterate.
there is NO leaner or richer.
just more or less of the pilot air and pilot fuel mix at idle.
if every thing is correct the factory settings work perfect.
everytime

[CaptRandy]

Rod, I have 200 HP 1991's calls for 7/8 port and 1+1/4 stbd. Is that looking to engine for stbd and port or the boat for stbd and port? Confused.

[rodbolt17]

the pointy end is the bow.
port is to your left when facing the bow stbd is on your right.
thats how port and stbd work
its the same for everything on the boat.
keeps the confusion down.

[CaptRandy]

I was hoping you said it that way.