I got into a Scrambler 50 trying to help a friend out.
I was told it is a 2004.
He has had it for a while, but it never really ran correctly.

I have it running now, and mostly it is good.
Disassemble the carb and clean it out, it was fairly clean though.
Removed the gas tank and oil tank and cleaned both out.
Replaced with new gas and 2 stroke oil.

Issue I am having is:
It needs the choke on to make it run decent at all times. Engine runs ok with the choke off after warm, but better with it on.

After I go past about 50% throttle, it falls off and while not stalling, it doesn’t go or really move. Once I roll it back then it will take off again.

I’m no pro with carbs, but this carb only seems to have one screw on it, and I have gone in and out with it and have minimal differences in performance. Neither direction has done anything for the past 50% throttle issue.

Can anybody give any suggestions as to what I might look at next? The whole thing is stock, nothing has been modified so I wouldn’t expect it needs different jets or anything.

Thanks!

 

If you just cleaned this carb without replacing the needle and seat,could be the cause or may still have a stopped up pilot or main jet, especially since you have to use the choke. This a sign of lean condition. These carbs are cheap enough just to replace as the oem needle and seat from Polaris would cost twice as much as an after market carb.Average air screw setting is 1 1/4 to 1 3/8 turn out from a lightly seated position. Doesn't matter if it's a Scrambler,Predator,etc as all the 50 carbs are the same.Only difference was that the early ones had an electric choke.2004 2005 2006 Carburetor Polaris 50 Predator Manual Choke Carb New | eBay

 

Ok cool...thanks for the info.
That is what I am looking for, a sort of base starting point for each of the screws.
I didn't know about the air screw, so I have that one to mess with.

Otherwise if it doesn't do anything, might be able to afford to throw $30 at a new carb to try it out and see if that fixes it...

 

Ok, so I finally went to mess with this thing a little more over the weekend.
Trying to start it, choke on, simply won’t start.
If I cover the opening of the carb with my hand about 90%, it starts and runs.
After getting it warmed up, I was riding it around a little and notice that if I push the choke cable in (choke off) that it will stall out.
This kind of proves that the choke is not really choking enough when trying to start, and also seems like its lean when choke is off.

Looking at the carb where this cable goes in, there isn’t really any adjustment for it.
I’m curious if you can adjust the choke or if its just a straight install the cable and that’s it?

Putting the airbox on and now I can run it full throttle without it nosing over and stalling.
But, choke has to be on in order to keep it running.

Progress, in the right direction, but I'm looking for perfection now.

Thanks for the help!

 

The manual choke versus the electric choke was never much of an improvement on starting the youth model 2 strokes. We received an early "in house" bulletin about blocking off the air box tube inlet tube with your thumb and they'd crank right up. Once warm,no problem on restarting.Problem was they don't have enough of an engine vacuum to pull gas when cold with either style choke. If you still have to use the choke to make it run after starting,something still sounds like it's stopped up,either in the jets, the orifice in the float bowl itself is stopped up,etc.The air box has to be on or it's really too lean to run right also. Shows the last Scrambler 50 to be a 2003,but really doesn't matter as they're all the same. As far as the choke adjustment,can't remember it it had an adjustment or not,but if it doesn't have one at the carb itself or choke assy on the bars,look down the cable to see if it has an inline adjuster and sleeve. If this carb gets to be more of a pain,don't forget the link to the cheap replacements.

 

Yep, everything you've stated makes sense. I was figuring there was not enough vacuum to keep it running or start it.
Still made huge progress this past visit.

I'll check the cable again for any sort of adjustment in the middle.
I've got it in my mind about the cheap replacement, but with the progress made, I like the feeling of getting it going without having to buy anything, but, its only $25...

Oh, and I also wonder if you know, is there a timing adjustment on this machine?

Thanks!!!

 

Timing is set by the stator plate mark to the case mark,plus the pick up coil at the stator along with the cdi take the place of the old points and condenser as far as ignition timing and advance.