You still have to remove every jet and clean them manually, not while they are still installed on the carb. That does NO good whatsoever. Get a small piece of wire as well to use while cleaning each jet when they are off the carb not installed.
Pull both of those carbs off the machine and disassemble them down to each part and clean them top to bottom. Leaving the carbs on the sled and just cleaning them from the bottom does nothing. I posted links to service manuals, they have in there how to do all of that.
"never did the top" meaning these are Makuni flat side carbs. According to a video I watched, I took the bottom apart (where the hose traps and floats are) and cleaned all the jets, floats, etc. However, I never took the top part off to access the main needle.
Okay you really need to disregard that video it is telling you the wrong way to do a carb cleaning.
When doing a carb cleaning they need to be pulled FROM the sled completely. What I do is this....
I take a white marker pen and mark on the side of it C for clutch or #1 and S for Stator or #2
I then pull the air-box, loosen the clamps on the carb boots and pop out the carbs.
I then slowly unscrew the top of it where the cables are going in and slowly pull out the entire venturi assembly and all. Making sure that nothing falls out. Do make sure if this does happen once the airbox is out put a small box or tub underneath the carbs.
Now I pull the bottom drain hose off to get rid of any fuel into said tub.
Now do this to each carb slowly, also while the cable and venturi's are sitting there doing nothing spray them down with some good carb cleaner CRC or Gumout not cheap Walmart garbage
With each carb off of the sled take them to someplace you can clean them on a nice flat surface
Grab a notebook as well as you will need this for part of the carb cleaning. Also have a tub for the clean parts as well.
Drop the bottom off of it where the 4 screws are, take the gasket off and set it somewhere it will not get ruined otherwise you are looking at buying a new gasket or carb rebuild kit.
Pull the needle/seat off carefully, inspect and make sure you DO NOT lose the clip! Set that off to the side and spray it with some carb cleaner.
Now those floats may or may not come out, ICR on those but those should be ok unless they are cracked.
Now you need to go to the side where the mixture screws are. Make a mental note or write down where each one goes.
For the Idle screw, screw it in to seated and while you do that COUNT how many turns in it took you.... i.e did it take 1.5 turns and it was seated? Regardless of the number right now in the notebook, carb C or S or # 1 or #2 Idle screw needs to be backed out 1.5 turns from seated when re-installing. With that screw out that also needs to be sprayed down with carb cleaner and have a piece of wire possibly run through it as those can get clogged as well.
For the rest of the screws the same instructions apply, count how many turns in each one takes till it is seated, mark it down in your notebook and the type of screw, clean them and set them off to the side with the rest of the clean parts.
Now you can take out the rest of the jets one by one, spraying them down with carb cleaner, cleaning them with a piece of small wire also and set off to side.
Do that with every jet including the needle! One of them will also have a c-clip on it right down in your notebook what position that c-clip was in as it makes a difference.
Once EVERY jet is out and cleaned let them sit while you work on the main body.
Now with NOTHING in the main body of the carb spray it top to down in carb cleaner DO NOT let it sit in carb cleaner for more then a couple minutes.
Take a soft toothbrush and scrub that thing top to bottom, take that small piece of wire and clean each passage thoroughly, take a compressor or canned air and spray it into the carb body several times as all it takes is a very small piece of gunk (which FYI I think is part of your problem along with not cleaning them the right way) to make sure nothing is left. Scrub it wherever you see yellow or green as the type of fuel we have these days just gunk's up a carb bad.
Also when done with cleaning the 1st carb put it back together and set off to the side so you are not mixing up or switching parts from one carb to another.
Before putting the carb back together give each jet a quick once over with the wire again and verify by looking in there nothing is left. But it back together in reverse of how you took it apart. If any of the parts are still wet them use the compressor to dry them off.
I was doing general preseason maintenance and thought I would snap some pics to help out those that would like to do minor cleaning and maintenance on their rack Mikunis. These came off my 2006 RMK 600, they are TM38 carbs. First remove the airbox to access the carbs. Disconnect the...
I am not sure if your flat slides are rack style or not, but with Coolhand's explanation and a few pictures, you should get a pretty good idea...
Also check over those carb boots VERY WELL! I can't stress that enough as all it takes is one of those to be cracked and you will have issues also. Especially since that is a reed system. You need to clean those reeds every pre-season as well and if it has the VES Valves in it, those need to be cleaned right now also. I know it is a PITA do to this stuff but it has to be done otherwise you end up with problems like you are explaining.
And thanks Dan! I figured I forgot something but I sat here thinking about it while watching ESPN and came up with all of that in my head in about 5 minutes,lol. I just had to get it down from me brain to me fingers to the keyboard somehow so he would understand what I was thinking in this messed up brain of mine,lol.
The reeds are in the intake behind the carb air adapters. You will need to remove the screws to the adapters to remove the reeds. The most common issue with reeds is damage (chipping) and wear where the reeds won't seal any more, which leads to an air leak. If you hold the reeds up to a light source and you can see light, it is probably time to replace the petals or go to after-market reeds. Some folks have been able to turn the reeds over and that can give a bit more life out of them, as well.
I just removed mine on my 600 RMK and they were really dirty, so cleaning is also something to look to do.
I'm not sure where you guys got the idea that I cleaned the carbs while still installed. I did take them off, but only cleaned the pilots by pulling the bottom off. I soaked them in gummout carb cleaner. Since you insisted, I just took the carbs off again this morning and reclined the 3 jets at the bottom AND removed the needle from the top and cleaned it too. Im skeptical this will solve the problem as everything seamed very clean. No wear and tear on the needle and all pilots seemed very clean. None-the-less, it's all clean and ready to be reinstalled.
Before reinstalling, I took one reed out. I found no "damage" but there was a little bit of light leakage. I flipped a side to see if it would improve, but it seems worse flipped. I'd say there was a 1 MM gap on one reed which is now maybe a 1.5 mm gap. Do you think this could be the problem?
I'm also still wondering about the ceasing to start with fuel dumped down the heads. Does it seam weird to you that one minute it worked and the next not? There's still spark. Perhaps not enough? Perhaps its all the reed?
Yes we get that you took them off but just cleaning just the jets isn't good enough. The entire carb needs to be cleaned. Doing just the jets is lazy, also you need to pull those mixture screws out and clean them. They also can get stuff in them and need to be cleaned. If you didn't do them then you need to. How else does those mixture screws work? They also have the ability to get gunk in them causing it not to run. Once you get that done and you reinstall and it still has issues well then we go to this step. You go to the service manual and find the carb settings, set them to what stock is for your carb as there was 2 types of carbs used, the Keihans and the Mikunis, you said you have Mikuni so set them to the stock Mikuni according to the Polaris Service Manual. If you have issues still then it is time to check compression if you haven't already. Low compression will cause it not to start. You need at "least" 110lbs for it to run properly, if it is below 100 then you are looking at a definite top end job at the minimum. Most of those engines usually sit at around 120-130lbs of compression per side.
As far as the reeds go Dan will know better then me.
If you flood the engine and it doesn't clear by pulling the plugs and pulling the rope a bunch of times, there are two small plugs under the exhaust. If you pull those plugs out, any water/fuel/oil that is in the crankcase should drain. If you remove the small plugs, normal would be a small amount, maybe less than a teaspoon. If a lot more comes out, there could be other issues.
One other issue that could cause fouling would be a hole in the fuel pump diaphragm. If that has a hole in it, raw fuel will leak into the crankcase through the hard impulse line that goes from the fuel pump to the opening on the crankcase. If you remove that line to examine it, it should be dry. If it's wet, you may want to look into rebuilding/replacing the fuel pump.
Sometimes I have had to clean the carbs as many as 4 times before I got them where they would adjust and allow the engine to start. Along with the jets, take a small wire (one strand of Cat-5 works great) and poke it into all the holes in the carb. When the gas evaporates (especially gas with alcohol in it), it leaves varnish and can really clog things up. Some of the openings are pretty small and clog easily, so running the wire into the holes can sometimes clear a clog.