Yam 50TLRB sneezing, coughing, bubbling

[palmbeach161]

New to boats and outboards. Bought this outboard in 2008. At sea trial it would not power up when in gear--idle fine. Previous owner had carbs cleaned--ran fine. Sat up over winter. Spring 2009 would not power up--carbs cleaned --ran fine, end of summer 2009 sat up for a month--would not power up. Carbs not yet cleaned. After reading many posts on this great site I will remove all old gas and Ethanol and replace with fresh, use Stabil marine at strong dose, install Racor water separating filter (10 micron). My questions are: Will the carbs being gummed-varnished up cause the motor to sneeze, cough and occasionally cause a large quantity of air bubbles to come out of the exhaust? Also is draining the carb bowls better than running the motor out of fuel? Would a 2 micron filter be better than a 10? I have bought a Yamaha Service Manual and will clean the carbs myself this time. Cannot afford to pay $350-400 to do this. I have cleaned and installed carbs on trucks, tractors, mowers and other IC engines for years. Does anyone have any cautions-suggestions before I do the carbs on this Yammy? Thanks in advance for any replies.

 

[rodbolt]

Re: Yam 50TLRB sneezing, coughing, bubbling

simple carbs.
pay close attention to the service manual for linkage adjustments.
pay VERY close attention to the position of the #2 cyl oil line when reassembling. pinch it between the carb and the intake and the motor goes POOF.
either clean and rebuild your fuel pump or replace it,any debris in the body cavities will feed to your freshly cleaned carbs and you will have to do it all again.
you simply CANNOT run the fuel bowls dry,aint gonna happen.
however each fuel bowl has a drain.
I reccomend for anything more than a 30 day layup to drain the carbs and fuel lines.

 

[palmbeach161]

Re: Yam 50TLRB sneezing, coughing, bubbling

Thanks rodbolt. Will pay close attention to the #2 oil line and go through the fuel pump as you suggested. Appreciate your help!

 

[palmbeach161]

Re: Yam 50TLRB sneezing, coughing, bubbling

Here is an update on this problem. Bought an ethanol test kit--no ethanol was in gas when "no power" problem occurred. Removed all three carbs, soaked in one gallon can of carb cleaner. Installed new carb kits($99 for all three). Found that the top and bottom carb were very clean inside. The middle carb main jet was full of crap. Also the middle carb float bowl drain plug was completely stopped up with very hard crap(had to use a small drill bit to remove it). These plugs are drilled and cross drilled so that you do not have to remove them all the way to drain the float bowl. Removed and went through the fuel pump--it was clean. Installed Racor 2 micron filter/separator in fuel line. Treated new gas with Stabil marine and Yamaha ring free at heavy rate. Followed link and sync instructions in Yamaha service manual and set idle as instructed. In the water the Yammy now runs better than it ever has since I have owned it. It runs like a scalded dog(no animals were harmed in this repair). After finding all that crap in the center carb I have to wonder if either of the two "technicians" who worked on it before bothered to remove the center carb. I look forward to a fun summer of boating, except for the fact that I live in an area that may soon be affected by the BP (big problem) oil spill. THANK YOU RODBOLT FOR YOUR HELP!!

 

[rodbolt]

Re: Yam 50TLRB sneezing, coughing, bubbling

ditch the 2 micron.
its for diesel and is to restrictive and will cause exccessive and premature fuel pump diaphram failure.
10 micron is the reccomendation.
othet than that its sounds good to go.
but like I say, you can rebuild the carbs for breakfast,get debris or watery trash in them at lunch and guess what ya get for dinner?

 

[palmbeach161]

Re: Yam 50TLRB sneezing, coughing, bubbling

Thanks again rodbolt. I will replace the 2 with a 10.

 

[rodbolt]

Re: Yam 50TLRB sneezing, coughing, bubbling

good luck, I reccomend the blue startron with everytank,it contains a biocide to aid in curbing the bacteria that E fuels support.
I also reccomend draing the carbs for any 30 day or longer layup.
good luck on the BP thing.
we are worring it will hit the atlantic and give us a taste as well.
happiness is clean fuel systems and tuned up cooling systems.