I have almost the same problem with my Suzuki DF2.5. It stalls when it is warm.
I suspect the cooling since there is nearly no water coming from the exhaust. Do you have the same experience?
Did the new sparkplug help?
I have problem with my Suzuki DF2.5 which looks like your. It runs poorly when it gets warm, even shuts down when it's warm. I have a question about the cooling, the exhaust is hardly pooring out water even when its in full throttle. How does your water exhaust looks like?
Second question; did...