Hi All, I have a ’86 250 Fourtrax. I use it mostly for duck hunting before light. So I need dependability to start it and keep it running while cold. But it is choke sensitive. A medium choke causes lots of smoke. If I give it too much choke it won’t run even when cold. And if I back off on the choke the idle is too low and it starves out. I can’t seem to be able to access the choke cable at the carb connection. Nor do I have any schematics of what it looks like inside. I removed the carb from the engine but it is held on still to throttle cable and choke cable. Do I need to remove these some how to make an adjustment? And how would I do this? And what is the proper adjustment that would either increase idle by increasing choke or adjust choke so that it doesn’t choke out the engine as, is usually the case?
I down loaded an owners manual but the pictures are so bad that it is almost useless to see what they are showing. Are there any other downloads that are better? And Carb specific? I spent an hour looking at old threads to no avail.
It seems to run pretty good other wise, as I tried to clean out the carb to where it runs good on flat land use anyway. It does seem to run rich as you can smell it at the exhaust even when it is warmed up. Always been that way, but doesn’t seem to burn much oil, even though engine seem loose. Also the cam chain tensioner is loose. Someone seemed to have welded it to build up metal. Won’t this scar the cam? If not, should I try to do that again to keep it from ticking at various idle revs. And when I turn it off there is a loud clank noise often.

Hi All, I have a ’86 250 Fourtrax. I use it mostly for duck hunting before light. So I need dependability to start it and keep it running while cold. But it is choke sensitive. A medium choke causes lots of smoke. If I give it too much choke it won’t run even when cold. And if I back off on the choke the idle is too low and it starves out. I can’t seem to be able to access the choke cable at the carb connection. Nor do I have any schematics of what it looks like inside. I removed the carb from the engine but it is held on still to throttle cable and choke cable. Do I need to remove these some how to make an adjustment? And how would I do this? And what is the proper adjustment that would either increase idle by increasing choke or adjust choke so that it doesn’t choke out the engine as, is usually the case?
I down loaded an owners manual but the pictures are so bad that it is almost useless to see what they are showing. Are there any other downloads that are better? And Carb specific? I spent an hour looking at old threads to no avail.
It seems to run pretty good other wise, as I tried to clean out the carb to where it runs good on flat land use anyway. It does seem to run rich as you can smell it at the exhaust even when it is warmed up. Always been that way, but doesn’t seem to burn much oil, even though engine seem loose. Also the cam chain tensioner is loose. Someone seemed to have welded it to build up metal. Won’t this scar the cam? If not, should I try to do that again to keep it from ticking at various idle revs. And when I turn it off there is a loud clank noise often.