1999 yam c40tlrx idling rough

[Tsbeast1991]

Hey guys my timing was out of wack and it was set too retarded by 7 degrees. Guess my cdi went bad. However I got it into time right, and for a day on the river I accidentally turned my emergency fuel enrichment on stumbled on why it was running like shit. Now that I have it in time and that off it runs a lot better. However when I turn the air fuel pilot screws all the way in on the top screw it dies ( which is normal) but when I do the middle carb and maybe even the bottom it doesn’t die, motor actually runs a little faster. Is it possible I gunked up my middle carb? I had just rebuilt them 6 months ago, but then ran into small issues. I have good fuel, spark, new plugs.

[robert graham]

Remove each idle mixture screw….spray carb cleaner into each orifice, let it sit a while….then spray compressed air into orifices….replace each screw and reset each one about where it was….this may help…I’ve done it before and it fixed the idle problem…

[99yam40]

I do not see how gunked up carbs would cause 2 and 3 to run too rich

[Tsbeast1991]

robert graham did u remove float bowl screws to relief air while u did that? With carbs on motor?

[Tsbeast1991]

99yam40 what do u suggest? I got it timed right now from the bad cdi box. Just seem like it has a slight miss that’s all. When I close the top pilot screw it bogs out but not middle and maybe bottom aswell

[99yam40]

look for something that would give too much fuel to those not acting right.
so what position do you have the red lever set at?
auto or off?

have you checked the fuel pump diaphragm to see if it is leaking into the crankcase thru the pulse port in #3?
what about the prime start diaphragm ?
I think pulse port comes from #2 crankcase

[Tsbeast1991]

99yam40 i appreciate all your help you’ve given so far man. I wish I could FaceTime you it running hahaha. But it has a new fuel pump but I should probably check the port just in case. The red lever “fuel enrichment” knob got knocked to on a few weeks ago and I realized it was on. But it’s set to “normal” now. As far as the prime start diaphragm I don’t know where that’s located, I assume in the little housing beside the fuel enrichment solenoid mounted to my middle carb? I can turn the red lever to “on” and it will bog my motor down and die almost instantly. Which is what it should do I think? I am thinking about re pulling my carbs and checking my reed valves maybe.. I ran it all night one night while it ran shitty with my enrichment lever set to on trying to figure out what my problem was lol. Since then I’ve put new plugs, corrected timing from my bad cdi timing, and checked spark. It runs totally better now that it’s timed right but still seems to miss a little. And that’s how i noticed pilot screws on middle didn’t affect engine idle at all

[99yam40]

setting the red lever to off after warmed up will keep any extra fuel from running thru that system,
you can try that, but that would affect all 3 cylinders

but that will not stop fuel from getting sucked thru the PS diaphragm if it has a hole in it, and I am thinking it should affect #2

[Tsbeast1991]

99yam40 still has a slight miss/ rough spot… does the cdi have any other affect than con*****ing timing? I know mine isn’t working properly but I did manually time it properly. All 3 cylinders are 7 atdc. It also seems to smoke pretty badly even with the correct mixture after warmup.. all coils show correct ohms. New plugs, fresh gas, the PS diaphragm looks good, however the rubber boot on top of the needle that controls the ps ripped pretty badly so I put tape on it.. the rpms jump from 720-900 at idle. It’s like it has a slight miss. Will pull plugs and see if they re fouled before I replaced one of the coils. And also check my thermostat. I also noticed when I press the throttle down really fast, it seems like it has a kinda bad delay.