QuestionQUESTION: I have a 2000 JD 325 with a 18 hp twin Kawasaki,The engine was surging at idle into mid range, so I was going to pull the carb and clean. But when I got started, I noticed that the fuel filter was empty. I checked out fuel pump and it was bad. I replaced pump, and the surge is gone now. Here's the question. I pulled both spark plugs after mowing (with new pump installed) and they look a lean or should I say clean. I need to know where to base line my carb adjustment.There's 2 adjustment holes thru the top platic cover of the engine. one is adjusted about 3 1/2 turns from bottom, and one is about 1/4 turn from bottom.thanks in advance Mike.
ANSWER: Mike
When you adjust the carb when it is idleing adjust it till it starts to run bad then bring it back till it smoothes out then 1/8 turn Do the same for the high speed while it is running fast
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QUESTION: Is that what the 2 jets are ,high and low speed?
AnswerMike
yes the low speed Idle adjustment is one set screw and then the other is the one you set at high speed.
Initially, carefully and gently turn the two mixture controls in until they just seat.
Note: "In" means clockwise (the way you would tighten a normal screw) and "out" means counterclockwise (the way you would loosen a normal screw).
CAUTION: do not force them - you are not trying to tighten anything - as you will damage the needles and seats which will require replacement of the needles or entire carburetor. Then back them out 1 to 1-1/2 turns. Set the idle speed screw 1 to 2 turns beyond where it contacts the throttle plate. Refer to your engine manual for specific recommendations! These settings should allow the engine to start and run, though perhaps not entirely smoothly or with great enthusiasm.
Start the engine and allow it to reach normal operating temperature - a couple of minutes. Make sure any choke is off once it is started and running stably. This will also flush any old deteriorated gasoline from the carburetor!
With the engine throttle control set for the maximum recommended rpm, very slowly rotate the main mixture screw counterclockwise (loosen) until the speed begins to drop off due to too rich a mixture. Then, rotate the screw very slowly clockwise (tighten) until the engine begins to cut out. Very slowly means a fraction of a turn at a time - then wait a few seconds for the adjustment to have an effect. Note the number of turns between these two positions and set the screw in the middle of this range.
Repeat this procedure with the engine throttle control set to the idle or slow speed position but using the idle mixture screw instead.
If there is a high speed adjustment - possibly on the throttle control itself or the throttle control bracket, it is best to set it using a tachometer. However, it is possible to do a very good job by comparing the speed by ear to an identical type engine that is set correctly. See the section: Setting engine speed.
WARNING: if in doubt, set it low. It is better to end up with a scraggly lawn than bodily injury or a blown engine! Note that by ear, 2 stroke will always sound faster than 4 stroke engines for the same output speed because they have twice as many explosions per rotation of the crankshaft!
Set the idle speed adjustment just high enough that the engine idles smoothly and isn't about to cut out. A tachometer can be used to set it to specifications but there is no risk is just adjusting it to idle smoothly.
Test the engine under load. It should respond to load pickup immediately. An engine that dies is set too lean. An engine that runs roughly when picking up load is set too rich. Make a small adjustment (i.e., 1/8th turn) and test again.
