Friend of mine has a 40 ho yamaha that makes a “chirping noise” every several seconds. almost like some type of pressure builds up then gets released. the engine also seems to pause at the chirp.
If a picture paints a 1000 words, here is a you tube video.
http://www.youtube.com/watch?v=Z5y-rSh4AO4
any ideas???
SeaPro SV1900 CC
sounds like the motor is beging to seize up from overheat or lack of oil, etc…
take the spark plugs out, and spin the motor over by hand, and see if its free, or it “catches”
I’m now at www.teamcharlestonmarine.com
thanks for the input. here is some additional information he provided:
it only does this at idle…runs fine at speed. We went all the way around the lake the other day. It seems to be oiling fine…note smoke…and it is using oil. Some people mentioned carbs (lean chirp), but it sounds like it is coming from lower down. Could this be a seal?
Maybe the auto oiler is not working well at low idle, but is at speed??
SeaPro SV1900 CC
I am the friend. Some new info…took out thermostat, some rust, but appeared to be working. Good pee-hole flow. Starts chirping even before the engine is warm to the touch (within 15 secs or so). It does seem to be getting oil and the motor turns freely. Could this still be carbs or something mechanical like seals?
I would still suggest taking out the spark plugs, and turning the flywheel by hand., and seeing where the stick is.
it may only be noticeable at idle, because at higher rpms, the rotation speed would prevent the stall
I’m now at www.teamcharlestonmarine.com
Drive shaft bushing?? Mine makes a little squealing noise at times on a Yamaha 75 4 stroke.
Don’t you love trying to describe sounds from a motor in words? 
Chris V:
I did this and the motor did not seem to catch anywhere. I did notice that one of the spark plugs was a little oilier than the others (I recently put in brand new ones). There are no oiling problems or overheating problems (no alarms, cool to the touch, oil being used - I guess one cylinder could be starved??)
quote:
Originally posted by chris VI would still suggest taking out the spark plugs, and turning the flywheel by hand., and seeing where the stick is.
it may only be noticeable at idle, because at higher rpms, the rotation speed would prevent the stallI’m now at www.teamcharlestonmarine.com
its common for the bottom cylinder plug to have more oil on it! gravity!
19’ Key West CC 140 Johnson
16’ War Eagle 40 Yami
12’ Alumacraft 1954 Johnson 5.5
VOTE DEMOCRATIC ITS EASIER THAN GETTING A JOB!
Not sure I buy that argument, but it is moot…the oily one was the top cylinder.
quote:
Originally posted by tlreadits common for the bottom cylinder plug to have more oil on it! gravity!
19’ Key West CC 140 Johnson
16’ War Eagle 40 Yami
12’ Alumacraft 1954 Johnson 5.5VOTE DEMOCRATIC ITS EASIER THAN GETTING A JOB!
DRIVE SHAFT BUSHING.
You need to put a little grease on it but you’ll have to drop the LU to get to it.
if witht he motor turned off, and the plugs out, and it doesnt do anything, it may be a timing issue
I’m now at www.teamcharlestonmarine.com