OMC 120 issue

I have a 79 seaswirl with a OMC 120 with a 400 series drive. Engine runs great at WOT and most places inbetween. The problem is if i leave the boat in gear just above idle the engine struggles to run and eventually dies. This makes docking or any low speed manuvering difficult to say the least. I have just ran through the carb and cleaned it up. Any suggestions for what i should do next?

Also i am looking to use this boat to tow tubes or skis and was looking for a little more out of the bottom end ( i know its a weak motor so i dont expect much) any reccomendations on the best type of prop to use?

Thanks in advance for any help

 

still sounds like it is flooding or maybe enven running out of fuel.
Could also be faulty advance springs (usually due to corrosion) in the distributor and its running advanced at idle causing it to slow down under load and hence start to retard and so on.

For water skiing just prop it lower so it goes to the top of the WOT range and or drilll the vent holes in your prop

 

Could be a blocked a idle jet or the mixture needs adjusting or a plug or lead could be failing at idle etc. A good service and check over should sort out or identify the problem. Get the engine running properly before altering props, you might not need to do it.

 

Turn the two air/idle screws all the way in counting how many turns on each one. Then remove the screws being careful not to drop the springs attached. Using the tube supplied with the can, spray carb cleaner in both holes and let sit a few minutes then do it again. It is important that you insert the tube into the threaded hole in the carb to get the most impact. Be sure you have a flex adjustment tool for when you do the adjustments after restarting the engine. Re-install the screws all the way then back them out the same numbers of turns as before. Start the engine and after full warm up bring the rpm's down to 750. Adjust the screws 1/4 turn at a time to get the max increase in rpms with the adjustment on each screw. Then reduce the rpms to 500 and do the same. With the idle passages clean you should be able to idle in gear at 500 and give you great dock maneuverability.

Good LucK!!!!