QuestionI have a bushhog brand zero-turn mower (2 years old) with a Kawasaki FH721v engine on it. The engine only has 245 hours on it and has run good up until this year. I noticed when I went to start her up this spring that it didn't want to crank; turned over and over and over...just wouldn't catch and go. Normally, I could choke it and withing a couple revs, it would fire right up.
I did all I could think of (left over knowledge from many, many years ago working on my motorcycle and helping dad with the tractors and mowers). I drained both tanks, drained the lines, changed the fuel filter, drained the float bowl...finally occured that I had failed to put stabilizer in the tanks before shutdown (getting old and senile), so I got some decent cleaner, put it in the fuel and turned it over and over and over again - until it finally cranked. It ran like crap but got better over the next hour or two and was finally usable. I've ran it about 8 hours since then, but now it won't run again. I put a new air filter on, knowing that this engine is very sensitive to mixture, but it's the same. It has NO power, blows out black smoke (obvious mixture issue), and if I take off the air filter, it will run like a charm! Put the filter back on, and the exhaust shoots black again, and it's likely to shutdown within seconds. Both plugs are sooty black but good spark.
So, sounds like mixture to me - but I'm from the good old days when you could just take a screwdriver, find the airmixture screw and have a ball. This thing has the screws capped. Should I remove the caps and go at it, or is this more likely something related to the earlier problem I had getting it to run in the first place? Maybe clogged jets, etc? It's 40 miles to take this baby back to the dealer for repair and I don't want to think of the cost just to find out it's in need of a good carb cleaning. What options do I have to try out before I pull the carb and rebuild it? I haven't rebuilt a carb in many, many years (last was a 77 cougar if that tells you anything...), but I could still do it if I have to. Wish there was a miracle liquid to run thru the carb and fix it all! (what ever happened to pouring Marvel Mystery Oil thru the intakes...used to work...I wonder.???)
Any suggestions?
AnswerDo this exactly!
Tell the dealer "I want an air cleaner for an externally vented carburater". The new air filter will say on the top, externally vented carbs only. If it doesn't, tell him you want an AIR CLEANER FOR AN EXTERNALLY VENTED CARB!!!!!!
The medium in the internal vented carb is to dense and will cause rich fouled plugs.
As carb cleans go, this is easier than opening the hood on a 77 Cougar.
Also replace the plugs with NGK BPR2ES plugs. Don't let them sell you Champions. You want NGK BPRES plugs.
