Idle issues with F40TLR

[Matt Greig]

Hello,

I have recently acquired a 2006 F40TLR. the carbs were quite plugged up.
I spent many hours cleaning out the carbs. air / fluid now passes through all passages in all 3 carbs(accelerator pump passages were fun)

#1 carb (top) bowl was corroded inside accelerator pump bore, this was cleaned up, but required replacing check ball and making new brass plugs. I have a new bowl on the way.
I also acquired 3 rebuild kits, not installed yet though.

I am having a persistent miss on #1 at idle only, ie removing plug wire has no effect

swapped plugs on 1 / 2 no change
swapped coils 1 / 2 no change

vacuum behind all 3 carbs is very similar on a set of gauges
compression cold is about 110 - 115 psi

if throttle opened a bit, #1 kicks in.

so I am fairly confident on ignition working
Have had on water once and runs on throttle fairly well, console on boat blocks full throttle on con*****er, still rigging up boat.

if I unplug fuel line at motor, after a few minutes, #1 kicks in until gas runs out in bowl.

if I let extra air in vacuum test port on #1 it also starts running at idle

all this leads me to think #1 is getting way too much fuel at idle

I can screw the idle mix screw on #1 all the way in to no effect

is the assumption of too much fuel sound?

any other test i can do to nail this down?

i have heard a lot about these engine with plugged up carbs, i seem to have reverse on one.

I am waiting for new bowl, i will install all rebuild kits at that time.


as a side note, what is the hose assembly going from plate in between carb and #1 and to all 3 carbs do, just curious what its for.

Thanks for any help,
Matt

[TownsendsFJR1300]

Sync carbs / linkage?

[Matt Greig]

I Have adjusted carbs such that vacuum is the same at idle on all 3, this is what I understand syncing to be, or am i wrong

[99yam40]

service manual should have link and Sync procedures for your motor., need to follow them every time you put the carbs back on

the F40 was a problem child with the lean jets put in to meet air pollution standards

[Matt Greig]

looking at manual, it seems there needs to be small pressure differences between carbs. just got new carb bowl in, time to do rebuild kits.

i wonder if not synced correct if all primestart fuel could end up in #1 (its the one with primestart solenoid) and cause rich miss