Setting the idle on outboards.

Well my outboard motor is running alot better now and now ive got to figure out how to set the idle. Theres the high speed idle and the low. Ive got the manual but they arent always the easiest to read or understand so give me some advice if you have any.

Gary 

Most engines of your 'vintage' have two knobs attached to the carb that protrude thru the front cowling.  I assume you have these?

One is a low speed and the other is a high speed adjustment.  Some also have an idle adjust inside on the linkage to the carb.

I adjust the low speed first, this is a key to the idle speed and smoothness.  Rule is gently turn in all the way...DO NOT TIGHTEN.  then back out 1 1/2 turns (varies but this is a good starting point.  Start engine and let it warm up.  On idle turn low screw slowly inward until it sputters (lean) then read the number at that point on the knob.  Next turn it out until it sputters (rich).  read that number and split the difference.  then take the engine up in speed and do similar with the high knob.  Now re-set the low knob as it may have varied it the initial setting on the high fuel was off.  These are actual carb adjustments.  You can then look for an idle adjustment on the carb linkage (inside the cowling).  This is merely a change in the twist grip handle setting.  Many engines don't have them, some do.  It will only require a slight turn on a small bolt (3/16) to increase or decrease the idle RPM (the earlier adjustments will still control the fuel/air mixture).

On old engined folks have often abused the high/low neddle valves by turning them in to far.  This makes a groove on the neddle valve inside the carb and makes them difficult to adjust, as a litlle turn increases or decreases the fuel rate.  If really bad you can take out the neddles and lightly sand off that ridge (or replace).  Often times the neddle valves tend to move with operation, which changes the lean/rich mixture.  So record those numbers and check them.  If the vibration causes on to move during increased operation hours, often it is an easy fix by tightening the brass cap/valve sealing bolt where the brass neddle valve enters the carb body; not unlick the same way you stop a stem leak on a water valve.

BEAR

Early I said I suspected the diaphragm fuel pump.  The suggestion Mickey Rat gave about holding the tank above the motor (gives gravity feed) was very good to determine the pump problem.

That needle valve would be available.  I get parts for 50s motors thru dealers, yea they don't stock them, but can get.  It is an easy replacement.  And it can be fixed if it is grooved.

BEAR

Anyhow i decided to take my motor in to get serviced mostly due to the fact that the fishing derby is in 3 weeks and i dont want to bugger things up more than they are. Sometimes when i try to do things myself im an accident waiting to happen. Hes putting a fuel pump kit in and tuning her up for me. I never got a chance to try tuning it cause the fuel pump went on me so im not going to take the chance right now.  

Gary

I love learning about small engines but if it wasnt for the derby coming up id play with it myself. Speaking of which, a guy gave me a Jonsered chainsaw at a yard sale on the weekend but it needs a powerhead condenser and piston ring and the saw is in pieces so ill probably need some advice when i get around to putting it together.

Gary

Gary,

It's an OMC, parts are easy to get.  Try locating parts for a Chrysler 2 stroke or an old Elgin.  Those two adjustments on the front of the motor are the high and low speed "jets" not idle.  The idle adjustment is a stop screw on either the throttle arm or linkage at the side of the motor, not on the carb itself.