Honda 20Hp drama

[bkel]

hey all, seems like everytime i have to post on here it's because i have a drama that i cannot figure out, so i go to the world to find the answers to all my problems (well ones to do with pressure cleaning anyways!!)
My 20hp honda is behaving very badly at the moment, seems like it's running on 1 cylinder when the trigger is grabbed. There will be minimal pressure at the tip, then that dies down as the machine begins to cough and splutter. When the trigger is released the engine begins to pick up again! This will go on for between 5-20 minutes when all of a sudden the machine perks up and goes like it never had a problem, until I go to the next job and start the process again.
I have changed the plugs, drained the tank and carby, cleaned the carby, changed all filters(air & fuel)but to no avail. I did notice that when i had the airbox off there appeared to be condensation on the intake manifold(just infront of the fuel pump) which disapears when the machine gets going.
Help, this is killing my productivity waiting for the machine to clear itself and get going, any ideas??

 

[Mark]

The first thing that comes to my mind is
we need to determine if this is a fuel related
or spark / ignition related to pull the plug wire
on each

A quality fuel treatment that displaces moisture
may be in order if it is a fuel problem. Possibly it is
an ignition coil malfuctioning, lets narrow it down
to fuel or spark first then go from there.
[hello]

 

[Larry L.]

If it has several hours on it ajust the valves then start with the spark and fuel,ect.

Mine also started coughing splutting and findly it would die,I checked every thing and was going to order new coils.I ajusted the valves and its running like a new one,I'm still scatching my head on that one but it worked.

 

[bkel]

thanks men, just had a nights sleep on it and will do more testing today and report back later on. Mark i will test the spark, though when i changed the plugs they seemed fine at the time but i'll do the screwdriver spark test today. The machine has many hours on it, 3 years old with 6-7hrs/day 6 days/week, so it's been a great machine.
how did you go with those pump prices?

 

[bkel]

Just a short message... got it going. Adjusted the valves (they were right out!) flushed the fuel system (didn't do anything) did a spark test and there it was..... the right ignition coil was starting to clag out! Changed it over and she is running like new, well as much as a 3 yo machine can! Thanks Mark & Larry for the help.