How can I stall the engine on my boat when I'm bringing it back in? I've been pushing the throttle forward but it still keeps running. What am I doing wrong?

Have you removed your idle adjustment screw? Most of these carbs are factory set to keep running at a low idle and stalled by being grounded via a switch. In the boats, we typically remove this screw, usually a large black adjustment screw that you can easily turn with your fingers. By removing that screw, the butterfly is able to completely close thereby shutting down you engine by a forward motion on your throttle trigger once your linkages and/or radio is properly adjusted.

Just to add to what Scott posted. If you still can not get the engine to shut down with the throttle closed then either the butterfly is not closing correctly or you have a air leak between the carb and ISO block or ISO block and head.

I'm pretty sure I had happen yesterday what cheezwhiz is describing. It is a horrible feeling. I ended up lassowing my boat like a runaway calf by throwing a rope in the water and running over it with the boat. When the rudder caught the rope I pulled her in and put my finger over the carb this killing the engine. I ordered a new block and gaskets immediately.

I am nuts about RC boats but I will NOT run if I can't get my boat to shut down via the TX. Please figure this out (it won't be hard) before you attempt to run again. Hemi and Cheezewhiz have you on the right track.

Always test the throttle before starting. The carb doesn't have a acceleration pump like a automobile carb does so there is no harm in flipping the throttle both ways a few times.

Well I just found out why you should be able to shut your engine down I just ran my boat up shore and bent the flexshaft. I think there are some problems with this motor I have a new one but waiting for some new motor mounts to come before dropping it in.

Also if your engine is too lean it will continue to run fully closed, as some air in the closed position is still allowed to run through. Try 1/8 turn out on the low side and see if it makes a difference.
Cheers, Chris

Right now it was running with the factory carb settings so your saying I should richen up the ls needle and this would help stop the engine? I think after I remove the flexshaft I'll give it a try and see if that works. I'm almost nervous to touch the settings since its running the other carb I had in place had a bad diaphram. What's the downside of having the ls needle set to rich?

wrong info sorry

Actually these engines produce the most power slightly rich, it's not a nitro motor.

I'll stick to firefighting then lol. Thats how it was explained to me, sorry. Might richen up my engine too

If I remove the idle screw and it still keeps running even after I push forward on the trigger to close does that mean there's something wrong with the head?

No, most likely a leaky carb gasket or debris keeping the butterfly from closing fully. I've had a carb last year that was defective from Walbro and wouldn't sit tight in the barrel. Typically there is never a problem with them, just a setting.

You still haven't removed that screw yet?!?!?!?

make shure you have enough negative travel on your servo to close the carb compleetly quick way to check is disconect the servo start engine and close the carb manualy if it still keeps running then then probibly have an air leak if it stops then adjust links hope this helps

Thanks for the info that helps out alot.