After Carb rebuilt, motor revs like crazy?????

bretmoua

Cadet
Joined
Mar 30, 2012
Messages
24
Outboard Motor: Mercury 150hp XR6 2 stroke with oil and fuel mixing on its own.

Ok, so earlier this year, I have replaced the thermostats, fuel pump, fuel filter, water pump, new fuel line and bulb, and everything ran fine until a week ago. I took it out last week and noticed that my motor stalls and will not go when I have the throttle lever all the way down. It will just stall and not pick up speed like it would normally do. I timed it and it took about a minute for it to engage somehow and pick up speed. So today, I decided to rebuild the carbs. After spending half the day rebuilding 3 carbs, the motor starts up better but there is a slight problem now. Every time the boat starts up, the boat revs like crazy even though the throttle lever is in the neutral position. I double checked my connections and everything is put back like the way they were. Has anyone experienced this problem before? Please help.
 

BonairII

Commander
Joined
Jun 7, 2011
Messages
2,727
Re: After Carb rebuilt, motor revs like crazy?????

Could you be possibly running lean? If not, make sure that the butterflies are closing properly when you throttle down.
 

Dave1027

Lieutenant Junior Grade
Joined
May 25, 2010
Messages
1,081
Re: After Carb rebuilt, motor revs like crazy?????

Sounds like you disassembled everything and don't have it all back together exactly correct. You need to re-sync the linkages.
 

BonairII

Commander
Joined
Jun 7, 2011
Messages
2,727
Re: After Carb rebuilt, motor revs like crazy?????

You need an OEM service manual for your motor.

"Syncing" refers to making sure that timing is advancing in 'sync' with the carb butterflies opening.
 

Dave1027

Lieutenant Junior Grade
Joined
May 25, 2010
Messages
1,081
Re: After Carb rebuilt, motor revs like crazy?????

Yep. Carbs, timing and control cables. You may have one or more carbs that are partly open. At idle they should all be completely closed.
 
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