Was told to ask Chris on this site about some yamaha carb questions. Is this a carb adjustment issue. Bottom carb will stall the engine when I plug it for a second. All three poor gas out when I do it. Top an bottom carb have oil or something in the throaght. All carbs have been disasembled and cleaned this year, not many hours since I cleaned them. Please see video below
Check the floats for proper adjustment. The engine will stall out when you cut off the air supply. Its the same as closing the choke.
Scout 185
Only the bottom carb kills the engine when I choke it out. You think that is the messed up float, or is it the top two?
Didn’t watch all of the video but I’m assuming this is a 90hp.
Mine used to act up like that if it sat up a while…Taking carbs off and a simple cleaning always did the trick…it was always the bottom carb same as yours…the linkage is very easy to disassemble and put back together…very intimidating the first time so I took pictures…
Most I ever had to replace were the three gaskets…good luck
why are you doing what you are doing?
the carbs should flood out like they are doing when you cover the intake while running
Chris I hadnt run the motor in a while so I was running it in the yard to make sure it would crank. I had been having a low speed stumble so I assumed it was carb adjustment. The low speed stumble seemed to start when I knocked the hell out of a submerged stump. I have since removed all three carbs, soaked and cleaned them. The low speed stumble is still there, inermidatly. The build up on two of the carbs concerns me, why not on all three. Also not sure why only the bottom carb stalls the motor out when I choke it using my hand and not the top two. Motor is an 05 50hp.
What should the starting point on the low speed needle valve be. Again 2005 50hp TLRD.
quote:I watched the video. ALL CARBS STALLED THE MOTOR OUT.
Originally posted by scmoose…Also not sure why only the bottom carb stalls the motor out when I choke it using my hand and not the top two. Motor is an 05 50hp.
This was just MY observation.
People on this thread will help you. Be patient. Answer ChrisV’s questions.
Only the bottom carb shut the motor off. I did answere chris’s question I believe. Ive pulled all the carbs soked them in carb cleaner, noticed two of the floats were slightly mis adjusted acording to the book. Ill put it all back together after thanksgiving to see how it runs.
no one ever likes my answers, but I only know how to fix motors one way
start at the beginning
check compression and then check spark on all cylinders
if that checks, then do a drop cylinder test to see if its hitting on all cylinders at idle
quote:The people who like your answers don't have problems with their motors. :wink:
Originally posted by chris Vno one ever likes my answers, but I only know how to fix motors one way
start at the beginning
check compression and then check spark on all cylinders
if that checks, then do a drop cylinder test to see if its hitting on all cylinders at idlewww.teamcharlestonmarine.com
www.joinrfa.org
There are many MANY of us who follow your posts. Keep posting and thanks, for keeping me out of the shop. 
Whats best way to do drop cylinder test?. Completly remove plug wire from plug and coil then run motor, shut off then move to the next one. I pulled a plug wire today and got zapped. Also can any one comment on the residue in the carb throats. You can see it in the video.
Had a friend ask me to perform surgery on him one time,still wonder what he was thinking now and then…
quote:
Originally posted by scmooseWhats best way to do drop cylinder test?. Completly remove plug wire from plug and coil then run motor, shut off then move to the next one. I pulled a plug wire today and got zapped. Also can any one comment on the residue in the carb throats. You can see it in the video.
what were your compression numbers?
did you have spark on all 3 cylinders?
we use these http://www.etoolpros.com/automotive-tools/LIS-51600.html
the residue looks like carbon buildup goo getting pushed into the throat when you choke it out. might have some blow by on the reeds
Ill have to run a compression check again, I dont remember the numbers from the last time I did it but they were all within a couple psi from each other. I get my hands on a compression guage and run them tomorrow.
All three cylinders are firing. I pulled the wire then started the motor. I could hear a small rpm change for each cylinder, plus when I ran the motor with the boot off of the plug, I could hear the coil firing, and jumping from the coil to the plug wire on each cylinder. Didnt realy care to run it that way. I did replace the plugs as the ones in there looked to have some carbon buildup. I tinkered with the idle screw on each carb. The further out I turned them, the more the motor smoked, and carbon was pooring from the exaust. Settled on 1 1/4 turns from the seat, exhaust looked good, motor sounded decent.
Update, from top to bottom Im getting 120psi, 120psi, 118psi. Ive confirmed all three cylinders are firing. What I did discover that when I pulled the plug to do the compression check, the top plug looked as I had just pulled it out of the box and put it in. I was concerend that maybe the plug itself was bad so I connected it to the plug wire, grounded it out and bumped the motor and it is in fact firing. So I moved the plug down to the middle cylinder and ran the motor for a minuite, pulled the plug and you could tell it had been combusting. I cleaned the plug and put back in the top cylinder and ran the motor again and it looked brand new when I pulled it. Looks as if there is no combustion taking place in the top cylinder. So I pulled the drain plug on the carb and the bowl had fuel in it. Does this mean some sort of intake issue, stuck reed or something?
See above answer. Why are you doing what you are doing?
Scout 185
Ive already mentioned it, low end stumble, I was also conerned with build up in the carb throats. I posted the numbers he asked for, then noticed top cylinder doesnt apear to be firing.
Most important question, how far is it from your house to Chris’s shop?