TOPIC: Merc 650 reed valve issue??

General questions regarding reed valve assembly. How do you check it? What problems can it cause? How do you remove it? Haven't torn an outboard apart before, just 4 stroke mower engines. Trying to get things set for the new prop I bought and found the idle stop screw was stripped out. Got a new screw and retapped the threads. Since I have a tach on it now, I see that my idle speed is way too high, but if I try to bring it down it goes haywire (lopes/pops). Could I be looking at a reed problem? And are there replacements available?
Thanks in advance.

I'm not sure if Boyesen makes reeds for the 650 4 cyl or not. If they are the same as the reeds in a 1000, then 'yes'.
A typical symptom of a broken are damaged reed is a mist of fuel mix being spit out the throat of a carburetor. Use of a bright flashlight or a piece of glass held out in front of a carb throat to 'catch' gas spit are a good way to see if a reed pedal is damaged.
If the beast seems to be running fine at around 1200-1500 RPMs, but begins to act up at a lower idle speed, I would try opening the idle jets a bit and see what happens.
Typically (at sea level) the 650-4 idle jets should be happy somewhere between 3/4 turn to 1.25 turns c-clockwise from gently closed clockwise.
Idle speed on water muffs should be set at somewhere around 1000 RPMs, as once the motor is down deeper in the lake water back pressure on the exhaust will pull the idle speed down to around 850+/-.
You may eventually find you can slow the idle speed down out in the lake, but for initial tuning-troubleshooting I recommend setting the idle at 1000 RPMs on the muffs.
IF the results of the tests conclude a fractured reed, we can walk you through the labor intensive 'heart surgery' required to replace the reed pedals.
Doc
Doc.

Thanks, Doc. Hope to be able to get the back end into the water and make the adjustments for the new prop before Sunday (the wife wants to take the family out on it). If it doesn't run right, well...you probably get the idea. Lol
Haven't really done anything with this thing since we got it in '05 except lower unit oil changes and impellers. Might check with you about timing, points and the other stuff I'm semi-clueless on.

Chuck

The way I check reeds is to run the engine up to about 2500 to 3000 and inject fogging oil down the carb throat. Have someone open the throttle wide and immediately kill the engine with the key. If white smoke puffs out of the carb you have a bad reed. You can hear them spit and puff at idle too, and the engine will be rough as Hell.