Hello Everyone. My 25L-7A tends to run fine when I start it in the morning. After it gets good and warm it will stumble like it is going to stall but never dies. It may run rough for a minute or so then will clear up and run smooth. After the engine is warm and it has sat some time it will not start again. Almost like a vapor lock. I just intalled a new regulator and no change. I am going to try a new mixer valve. It has new spark plugs and coils. I have been searching for a diagnostic tool. Are these available?