Hello everyone
First post, thanks for having me.
So I have been working on a 1987 trail boss 250 and it will not rev!!!! I've done the following: rebuilt carb w/kit, sealed intake, new air filter, re-cleaned carb twice, new spark plug, put old jets and needle back in, adjust choke, new gas, new 2 cycle oil and new battery. I worked on this thing for 6 hrs on Sunday. Runs the same with the rev limiter on or off, and limiter does work correctly in reverse. Starts and idles great. Been reading a bunch and not a lot of people have this problem. To me it seems like the rev limiter is kicking in on higher rpms. 1/4-1/2 throttle runs great, after that it falls flat on its face. My son races 2 strokes so I am familiar with these things but this one has me stumped. Any ideas would be great!!!
Thanks

 

Just pull the black wire to defeat the limiter,hook up a timing light an see if the light is continuous when it starts acting up or flashes in time with the miss indicating an electrical break down.Could be as simple as a resistor plug cap breaking down.Make sure you have good flow from the fuel valve to the carb. Plus you can pull the plug to see if it's running lean or rich. Crank seals may be leaking at higher rpms as old as they are if they haven't been replaced and do a good compression check also.If it's 100 psi or less it may be able to crank and idle,but may not be able to handle increased throttle.

 

That was it. Pulled the black wire runs great now. Thank you

 

One little module can cause so many problems..