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No fuel in one top carb

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Bnfram

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I have a 1999 Johnson 150hp V6 and not getting fuel to top carb on left side if you are standing at the back of the boat any ideas? Tried switching carb no change.
 
Bnfram said:
I have a 1999 Johnson 150hp V6 and not getting fuel to top carb on left side if you are standing at the back of the boat any ideas? Tried switching carb no change.
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Two possibilities:
1) Restriction in the fuel manifold (possible but not likely)
2) Restriction in the throttle body

Remove the fuel manifold, then squeeze the primer bulb. If fuel flows then your manifold is clear. BTW, you'll likely need new manifold O-rings if they've never been replaced.

If the manifold is fine, remove the carb then place a rubber tipped air nozzle over the manifold inlet hole. With very low pressure, blow air into the throttle body to see if it flows. If the air is restricted you need to tear the throttle body apart for a thorough cleaning and rebuild.
 
kevinj said:
Two possibilities:
1) Restriction in the fuel manifold (possible but not likely)
2) Restriction in the throttle body

Remove the fuel manifold, then squeeze the primer bulb. If fuel flows then your manifold is clear. BTW, you'll likely need new manifold O-rings if they've never been replaced.

If the manifold is fine, remove the carb then place a rubber tipped air nozzle over the manifold inlet hole. With very low pressure, blow air into the throttle body to see if it flows. If the air is restricted you need to tear the throttle body apart for a thorough cleaning and rebuild.
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Do you have any pictures of the manifold inlet hole by chance so I know what I'm looking for? This motor is new to me haven't messed with it at all do want to mess it up.
 
If one carburetor did not get any fuel then 1 cylinder was also starved of OIL.----Best post your compression values on this " new to you " motor.
 
Okay pretty sure I found my issue I was toldnfrom previous owner no fuel to carb I primed my bulb and had fuel to the bowl come to find out no spark on one cylinder. Does anyone know what compression should be? I have 95 psi across the board.
 
kevinj said:
I don't have any pics, but all the parts diagrams can be found here --> 1999 J150 Parts on Marineengine.com

And yes, 95PSI on all 6 cylinders on this engine is just fine. These were low compression engines so that number is good.
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Thank you for your help. I pulled the screw out of bowl last night and had fuel coming into carb when pumping the primer bulb. I went off what previous owner told me with the reason that cylinder wasn't working being a fuel issue. I finally had time to work on it last night and found no spark on just that side of the coil found bad ignition module replaced module last night with a spare one now have spark. Will run today on muffs and see what happens.
 
Bnfram said:
.....found no spark on just that side of the coil found bad ignition module replaced module last night with a spare one now have spark. Will run today on muffs and see what happens.
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Running on the muffs doesn't really give a good indication of running condition. A poorly running engine can sound great on the muffs without any back pressure on the exhaust. If you have a large barrel to submerge the lower unit it will give you a better sense of how it's running.
 
kevinj said:
Running on the muffs doesn't really give a good indication of running condition. A poorly running engine can sound great on the muffs without any back pressure on the exhaust. If you have a large barrel to submerge the lower unit it will give you a better sense of how it's running.
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Okay I'm going to run it tonight in a barrel anything I should look for? Do I need to run it in gear or out of gear?
 
You could shift into F & R but I wouldn't give it any throttle. You'll lose enough water out of the barrel just with the prop spinning slowly. Mainly it's just important to have the back pressure to make sure you're firing on all cylinders and running smoothly.
 
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