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mercury 40 hp 4cylinder 2 stroke carb issues

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bassforme

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2 months ago I bought a 1996 bass tracker started and ran fine until I wanted go faster it bogged and ran but wasn't going fast so I decided to push the key choke in and it took off, released choke and and would go half speed.I thought the carbs were dirty so I cleaned them up all looked pretty good needles,gaskets ect....put back the carbs now wont even idle or stay on,did notice the idle mixture screw top carb was at (lightly tightened)about 1/4 turn and the bottom at 1 1/2 turn before I took them apart and set them back the same I also set the floats as specified any ideas what I should try

1996 Mecury 40hp 4cycl 2 stroke oil injected (serial# 0G265924) dual WMA 9/10..13 carbs

thanks for any help
 
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bassforme said:
2 months ago I bought a 1996 bass tracker started and ran fine until I wanted go faster it bogged and ran but wasn't going fast so I decided to push the key choke in and it took off, released choke and and would go half speed.I thought the carbs were dirty so I cleaned them up all looked pretty good needles,gaskets ect....put back the carbs now wont even idle or stay on,did notice the idle mixture screw top carb was at (lightly tightened)about 1/4 turn and the bottom at 1 1/2 turn before I took them apart and set them back the same I also set the floats as specified any ideas what I should try

1996 Mercury 40hp 4cycl 2 stroke oil injected(serial# 0G265924) dual WMA 9/10..13 carbs

thanks for any help
Click to expand...
also did a search and couldn't find the right carb
 
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Factory manual for a 1994 40hp 4cyl.says: initial setting of carbs idle mix screws at 1-1/4 out. Try pumping the bulb to see if that helps with bogging ( fuel pump). You should replace all the fuel hoses and filters if you think they are origional.
 
Thanks for the replies, I replaced all fuel lines and I did notice that when I cover the top carb intake while running its dies..seems normal but when I cover the bottom carb intake it wants to go ...any ideas..thanks for any input
 
took apart used berryman dip soaked, blew out with air and put back together also took pics of everything I did .....(want to go fishing)...Thanks
 
So why did you set the top slow mixture needle at 1/4 turn out ?----Set them both out at 1-1/2 turn and test run again.
 
ok..when i bought the boat seemed to run fine different story when I got it on the water under load..the 1/4 turn was the way it was set.I will set them both as you advised...Thanks and will post results as soon as I get home
 
got the compression test done and I got 119 to 120psi on all 4 cylinders after I warmed her up....herd somewhere you have to have the throttle wide open but my throttle wide open prevents you from starting engine......going to work on adjustment...thanks
 
yup didn't make a difference on the Throttle position...I understand now:D.....ok put the mixture needle as you stated and engine seems ok not running great at idle but she's running strong at higher RPM'S...Thanks for all your help mgj4135,fastjeff & racerone ..time to go fishing
 
Do these 40hp 2 stroke outboards have reed cages like a 2 stroke dirt bike motor? My 1994 has been running same way. Runs strong for about 45 minutes than starts losing power and bogging. Will run steady at have throttle, but any more and starts bogging, sputtering. I messed with mixture screws and 1 1/2 is best. But still has issues after about 45 minutes of running
 
Jrz3bilt said:
Do these 40hp 2 stroke outboards have reed cages like a 2 stroke dirt bike motor? My 1994 has been running same way. Runs strong for about 45 minutes than starts losing power and bogging. Will run steady at have throttle, but any more and starts bogging, sputtering. I messed with mixture screws and 1 1/2 is best. But still has issues after about 45 minutes of running
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I was having the same issue, what I found out if the reeds are bad or stuck there would be no air being sucked in the carb, what I did was get a good carb cleaner like berrymans and soak your carbs overbite blow them out and yes a good air mixture is about 1 1/2 out, good luck
 
That particular 4 cylinder 2 stroke had reed cages way inside the motor.---Very reliable unless a motor was over revved with too small a prop.----Reeds chipped / broke on those.----Seagull feathers or rodent nesting material will be a problem for reeds as well.
 
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