I cnnot agree with the light bulb statement for these multifuels. We have many hours on our engines with no problems. We do not just use them for light duty. The same basic engine is used in White farm tractors. I have neighbors who have over 4,000 hours on them with no problems under hard pull conditions in the field. There is usually a contributing factor other than engine design to the failure. An analysis of the failure components will usually reveal the cause. If a rod cap bolt let go, it is usually due to over-torquing, under-torquing, or a faulty bolt. A person familiar with metal failure modes can look at the ends of the broken bolt and tell how the failure happened, and why.
Regards Marti