Ok, I have a Scag Turf Tiger 29 hp DFI that starts and idles fine but wants to die under a load ( going forward with high RPM or with the blades engaged ). The mower ran fine at the end of the season last year. So I pulled it out and changed the oil, Plugs and air filter in it before i started using it this year and it seemed to run ok but after i started to use it on the first yard it wanted to die when it was under a heavy load. After using it on that yard now it has gotten worse to wear it doesn't even want to go in forward motion at high RPM without trying to die. My first thoughts were the fuel filter is probably clogged with old gelled up gas, so I changed it and the problem was still there. My fuel pump sounded real loud and rough so I changed it hopping it would fix the problem but its still there. So my next thoughts were maybe the injectors were clogged so instead of disassembling the engine i ran some Lucas fuel injector cleaner through it but yet again another try failed. Last but not least i tried changing the voltage regulator thinking maybe the voltage was dropping under a load and again it didn't fix it. I was hoping maybe you guys could help with some ideas or maybe one of you have encountered this problem before on the same engine.
Turns out I only had a small issue after all. The valves just needed adjusting and it was real simple to do. After doing a compression check then following up with a leak down test i figured out that the valves were leaking. So I pulled the push rods and found that the when i pulled the push rods the valves quit leaking as bad. I then looked up how to adjust the valves and adjusted them. Now after another leak down test and compression test everything seems to be good.
