Atc 70 exahust RED HOT???

[1972mercury]

I have a at 70 and bought a sterdy exahust put it on a year ago without no problems now its not running so good took the carb apart thinking maybe some dirt inside that was perfect took it out for a ride last night and noticed that where the exhaust attaches to the head 6 inches of the pipe was RED hot! then when i would slow down then it goes away just when i open it up???

[shortline10]

Motor is running lean . Do a plug chop .

[1972mercury]

Maybe I might have to go 1 jet size bigger if the plug is white or gray when i do the plug chop

[hoosierlogger]

Valves might not be closing all of the way. Maybe a cracked, or bent exhaust valve too. Definitely worth looking into.

[dougspcs]

Spark timing issue or possible exhaust restriction could also be the cause.

[KASEY]

THATS AN EASY ONE... its been running great for a year.... and now its not.... the block on the the points is wearing down and changing your timing ... its retarding it to the point that you going to burn it up .... new points will fix the problem,,,

[ailll1]

Did you check your oil? After a year, it might have dripped some

My 200X did the same thing when I put a chinese carb on it. Had a 95 main, but stock its running a 110. To heat the exhaust red hot you need to be REALLY off on jetting. If you did not change carb and its clean you might wanna check somewhere else.