MF 135 with Continental bogging down

Also, you may have sediment clogging the system at teh fuel tank. Remove the entire sediment bowl assembly if you are not getting a good stream of fuel flowing into the sediment bowl.
I had this problem with a MF20 gas and you wouldn't believe the trash that washed out of the fuel tank. I had cleaned the fuel lines, filters etc. to no avail. Unscrewing the sediment bowl assembly and cleaning the tank fixed my problem.

THEN look at the fuel system. Open the tank valve and remove the drain plug from the bottom of the carburetor holding a can under it to catch the $3/gal gas. The flow should be fast AND continuous. If it isn't, start by checking the "secret filter" in the fuel elbow at the carb and work your way back to the tank valve. As mentioned, make sure that the fuel vent in the fuel cap is clear. If there's nothing clogging the fuel delivery then suspect a hung float or a restricted float valve in the carb. Rap the carb with a block of wood to free a hung float. If that doen't help, you'll have to remove the carb and disassemble it.

Seems to be fuel restriction...

You may unscrew the plug under the carb catch
the gas with a non metallic container. You shd have aboundant and steady gas flow there. If not remove the gas cap on the tank (vent may be blocked). If no change the fuel filter strainer in the tank or the strainer at the top of the bowl may me obtructed. If the gas flow is OK it may be caused by too old gas in the tank.. too old gas even mixed with fresh gas may do that.

You may check these few things and return to us for further suggestions.

Good luck

Yep