I have a 1996 sportsman 500 rebuilt top end new carb new starter. all levels good. but it idles perfect and wont rev up till full temp on radiator. any ideas why?
I wonder if these cheap carbs are jetted like the original? Yes sounds lean. The adjustable jet has a small effect on idle and just above. You can try dropping the E clip on the needle making it richer.
It takes 15 to 20 minutes of run time to accurately get a plug reading at the speed the problem occurs at and with no lead oxygenated fuel, the plug will stay white longer. The only plug reading will be for an overly rich condition. Black and fluffy is too rich and wet black is extremely over rich.
latebird is a very knowledgeable person.
what i'm going by is I have a similar situation going on and I put a black plug in and my machine turned it white in a couple of minutes just off idle. Yes it was dying and backfiring. I dropped the clip and it made it better but I don't know if that was a ''cure''.
ok the plan for today is......reset the carb..think ill change the clamps from the original to radiator clamps maybe thats part of it.
I wont give up ive rebuilt lots of motorcycles cars and a small engines but this one has me stumped....
I had a similar issue, and had to buy new throttle cable. That fixed it. Don't know if thats the answer for your situation, but maybe try adjusting your throttle cable, and feel it out with your throttle? Its free, and easy, so its worth a shot?
I can assure you that as long as the clamp that is on there is not damaged and is the proper size, no other clamp is going to improve whatever problem you might have.
You can over-tighten a hose clamp and cause an air leak! If the carb fits tight enough with the clamp you have that you can't pull the carb out as easy as with the clamp loosened, there is no need to change clamps. If you need to install a new clamp, get a narrow band hose clamp so the clamp will not be exerting pressure beyond the spigot of the carb.
ok carb reset someone asked about cables they are great and set right....runs a little better now when cold if I apply choke it will rev....guess need to adjust again
its almost positive to be the fuel air mix on the set screw on the front of carb
also should there be a clamp on the air filter in the box? I dont see one on parts diagram?
update....still does same thing but. now it sounds a lot better after I open the air fuel jet a half turn. as for the e clip I dont know what that is but im researching it
ok know what the clip is now. I always called it the needle adjustment. when the weather is better ill set it down to 4 and see what happens. checked the plug its really white. tho it did run better when I opened the air fuel mix a half a turn
UPDATE after reseting the air flow I went out and started it the next morning. hard to start but after warm a min I turned choke off hit the throttle and it reved up not great but it did. so it is the carb adjustment.
The fuel screw only has an INITIAL setting to get the engine started and warmed up - when the engine is at normal operating temperature, the fuel screw is adjusted to achieve the smoothest idle - the final setting can be anything from 1/2 to 4 turns dependent on the condition of the engine, valve adjustment, fuel used, air density and carburetor calibration.
for all the info thanks a ton. I got it running fine now. the problem was the the needle was corroded and stuck. I took the needle out of old carb installed it in new one reset the air fuel mixture screw and it runs great.
sorry been riding this quick thing. and if you cant tell me we will both know it was pitted and stuck now the original in the carb and ya better hang on it will fly
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