Yea thats the one .. Here is another version of the same thing that i actually used step by step , I have still not used a tach but ive got them dialed in to rip with no bogs or hesitations and I have no carb exp to speak of , everyone who rides my ski after doing this tuning procedure just grins !. QUOTE: There are several posts on guys having issues with tuning, If you follow this guide it will solve your problems if they are carb issues , and you wont need any help from a tuning X-PERT ! , BUT PLEASE REBUILD YOUR CARBS FIRST, with needle and seat,be sure you have clean fuel filter , and your lines are good ,''tank screens clean ? no water in fuel ,fuel vent works ,!!!!!!!!!!! I got these tuning tips from Watcon , I had NEVER before tuned a set of carbs before, I followed the instructions AND IT REALLY WORKS .so let me tell ya if your having trouble this will help you and you will be up and running so if you hear of anybody needing tuning help direct them to this post.... I guarentee results if you can follow instructions ! and You can thank RANDY from WATCON for the help !!! June 2006 Tuning tips: ......... AGAIN THIS W O R K S !!!
#1 Close the high speed screws to 1/4 turn from fully closed.
(some Polaris carbs do not have these)
#2 Set the low speeds at 1 turn open and test the ACCELLERATION ONLY from 2000-5000rpm. If it accelerates good, then turn in the low speeds another 1/4 turn at a time until it "lays down" from being too lean... Then open them 1/8 turn at a time until it accelerates smoothly again...
#3 Then open the high speed screws to 1 turn open and check the acceleration from 2000-5000 rpm again.. If it blubbers, and take a while to clean out, then turn in the high speed screws 1/4 turn and repeat until it accelerates quickly without blubbering..
#4 If it doesn’t blubber(too rich) on acceleration when you started #3, then open the high speed screws 1/4 turn at a time until it blubbers (too rich) on acceleration. Then turn in the high speed screws 1/8 turn and repeat until it accelerates quickly without blubbering..
#5 Now you are ready for HIGH RPM testing.. This is done in 100 Yard bursts only.. At this point you should have a smooth accelerating boat, and now you need to "fine tune" the peak rpm.
#6 Accelerate to peak rpm while reading the tachometer.( I don't mean a 1/2 mile cruise) only approx 100-200 yards.... Lets say you are reading 6910 rpm while monitoring the tach, now open the high speed screws 1/8 turn and repeat the test..
If you gained rpm. Then repeat the 1/8 turn again until you stop gaining peak rpm...
If you lost rpm, then close the high speed screws 1/8 turn and repeat the test. Do again if necessary until you are satisfied that you are reaching full rpm.
#7 Now you are ready to inspect the spark plugs (without idling to the beach) and look for any potential problems. After this phase, you can "tweak" each cylinder individually based on peak rpm readings to get the best individual setting for each cylinder.
*You will learn more tuning by rpm than visual inspection of the spark plugs* The tachometer never lies... DON’T USE A TINY TACH.....
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Symptom…..Falls on face when accelerating
Open low speed jets until it accelerates well with no flat spot or hesitation without worrying about peak rpm in short 100 yard acceleration bursts.
Symptom… Blubbers or misfires on acceleration
Too rich on hi-speeds. Close high speeds ¼ turn at a time until peak rpm is attained max 100 yard bursts.
Tuning procedures
Hold rpm @ approx 2000-2500 rpm for 30-45 seconds before each test to stabilize fuel flow & rpm
1 Turn in lo speed jets ¼ turn at a time until flat spot appears, open 1/8 @ time until it accelerates hard & smooth.
2 Open hi speed jets 1/8 turn at a time until it blubbers or misfires on acceleration.. then close 1/8 at a time until it accelerates hard & smooth to peak rpm.
Repeat steps #1 & 2 to double check before proceeding.
At this point you should be accelerating smoothly and reaching near peak rpm in short 100 yard acceleration tests.
You should be ready for some hi-speed rpm runs, fine tune with tachometer & plug readings... If rpm peaks and then falls off you are too lean - fatten up hi-speed and try again.. see #2
General rules
Each cylinder should be fine tuned as a separate motor/pipe/carb combination not all carb screws will be adjusted the same. Fine-tune each cyl with rpm/plug burn. Always tune in short 100 yard increments to minimize burn down’s..
If you have a difficult time... Turn in the hi-speeds ½ turn from existing setting then fine-tune the low-speeds first. See #1
Always do plug checks in the water under acceleration, don’t idle in to the beach. Take your plug wrench with you.
If ski dies, surges or picks up rpm when turning hard it’s either too lean, pop-off is too high, or too rich.
If it picks up rpm in hard right hand turns it ‘s usually too rich on the high speed circuit..
A gain in rpm in a hard left hand turn usually signifies a lean high-speed setting that requires more fuel.
The high-speed jet should be used to control fuel from 3\8 to 3\4 throttle opening
Use the hi-speed adjuster to fine tune throttle response from 3\4 to wide open throttle
The tuning tips apply to most vertical mounted carburetors with the diaphragms facing inwards and may vary if aftermarket intake manifolds have been installed.
