Mercury 9.9 carb jet question

[Jmac870]

First off I am not mechanically inclined but do have some basic knowledge. I have a fairly new to me 2005 merc 9.9 (203cc). The motor will start and run fine as long as I stay on the throttle but as soon as I let off the motor quits. I decided I would make an attempt to clean the carb out after watching a couple YouTube videos. I took the jets out an cleaned them but as I was replacing them I could help but notice the low speed jets screw on the top doesn't have a hole through it to draw fuel like the high speed jet does. There is a hole on the side of the jets housing that looks like it could draw fuel there but seems to have a plug in it. Or does the low speed jet draw fuel from the high speed side instead of straight from the bowl? Carb is apart right now and don't want to put it back together until I know for sure. Any advice would be greatly appreciated

 

[jimmbo]

Perhaps the low idle stop screw wasn't adjusted correctly allowing the timing to retard, or the carb to close, to the point where the engine couldn't run. The high speed jet is an orifice plug, hence the hole. The low speed jet is usually an adjustable needle that does not have air bleed(hole) in it. As for where the idle circuit draws its fuel from can vary from one carb design to another. A factory manual may explain the various circuits with diagrams. Plugs are on carbs to plug hole that were required to machine the internal passages of the carb. Some are designed to be removed for cleaning purposes, replacement for those usually come in carb overhaul kits.

 

[Jmac870]

Jimbo, thanks for the info I will look at ordering a manual

 

[ondarvr]

Common issue, the carb still has crud in the low speed circuit, it needs to be cleaned more thoroughly.

 

[Jmac870]

Success! I'm not completely sure what did it though. A mechanic friend of mine suggested the hole between the housings where the low speed draws fuel from may be plugged. I took the carb back off and blasted the hole the best I could but also sprayed the jets out again. So either that hole was plugged as my buddy suggested or Ondovr above was correct about not being cleaned thoroughly enough. Regardless, she idles great now. Thanks