9.8 mercury questions

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pointandshoot

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Feb 23, 2010
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hi all, i've been lurking on the forums for a while...LOTS of great info on here. i've got a few questions about a mercury 9.8 i bought from a co-worker with serial #715XXX. the motor starts and runs ok (even tho it takes a lot of pulls) and will idle all day long, but as soon as i try to apply the throttle it bogs and cuts out. i've taken the carb apart and cleaned it, everything looks fine (fuel pump and gaskets etc...), and the idle mixture screw is turned 2 full turns from seated but i'm not sure what the factory settings are supposed to be. also another thing that i am not sure of is the routing of my crankcase vent line. most of the pics that i have seen on the net show the crank vent line going back to the exhaust port cover, however mine comes forward and taps into the carb (is this right?). any help would really get me moving along and thanks in advance.

Craig
 
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Laddies

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Sep 10, 2004
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Re: 9.8 mercury questions

That line bleeds excess oil out of the lower main bearing and is hooked to the engine vacume to help pudding in the crankcase so may be hook to the intake cover or carb side. Your starting problem is a lean condition could be the float level is low, a lean mix on low speed, the small plastic venturi is not in the carburator. If richening the low speed helps don't worry about the basic setting that all it is a starting point.
 
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pointandshoot

Cadet
Joined
Feb 23, 2010
Messages
22
Re: 9.8 mercury questions

thanks for the reply that helps me out. i don't recall taking out any venturi of the carb while cleaning it. how is it held in the carb (i know most carbs have some sort of set screw)? if the venturi is missing could that contribute to my bogging issue? i know venturi size is very important on all engines and if i'm missing mine then i guess i need to sorce one out. thanks again


i just took a look at the carb and i couldn't see any visible venturi. the carb number is 1364-4929 which doesn't seem to be a very commmon carb (correct me if i'm wrong) for this motor. will the same venturi part #69764 still work for my carb? thanks in advance
 
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