yamaha 40hp chirping, sneezing at idle, any ideas??

[syclone01]

Just picked up a little boat with a 2000 40hp 2 stroke yammie premix only. It had been sitting for 8-12 months so i took off the carbs, they had a lot of crap in them. I cleaned them out, but didn't put new orings in as I wanted to get it back together quickly to see how it would run. The idle is rough with i assume some type of lean sneeze. What i've never heard before is this chirp noise, it chirps right about the time it sneezes. It's a real high pitched chirp sound. I haven't had a lot of time to google the internet as i'm at work right now but will check motor out again when i get home. Anybody have any ideas where to look first? I did sync the carbs and check timing as per the manual. The motor runs great once you get it past idle speed, Compression 124,126,123. I will check for intake leak when i get home as that's prob the easiest thing to do. Thanks for any help

[DoktorC]

The chirp is the lean sneeze coming through the reeds...sounds like the pilots are still dirty or your air screws aren't set right..

[martinc]

Replace lower crankshaft seal. Common failure. Thank's Martin

[1FASTLASER]

Replace lower crankshaft seal. Common failure. Thank's Martin

+1..... Had the same motor Celt yours is newer. Bout drove me nuts til I found the leak or chirp. That motor was a blast on a 14 ft boat

[Ray Neudecker]

Bad crank seal is likely the cause of the chirp.

[syclone01]

I opened the idle mixture screws from what the service manual says from 1.5 to about 2 turns, it actually idles now, but still has the sneeze/chirp every 10-20 seconds or so. I want to fix the actual problem, not mask it by opening the idle screws more than what I already have. If I pull the powerhead, can the crank seals be replaced without splitting the cases? I know some motors they are almost impossible without splitting, just really didn't want to if I didn't have to. Thanks for the help. The motor is on my little 14.5' scout center console, I got 38.1 out of it 2 days ago. I'm also looking to what I can do to the motor to get a little more power, if I pull the powerhead should I swap out the tuner for something else, or modify the one in there? Might as well do it while I have the powerhead off. Thanks again.