That does seem unusual, I have had some of the first pods at the base not fill out. They usually just rotted. I would not cut the vines that would be the worst thing to do. Limas are exremely prolific and do just fine with all the tangled vines. I wouldn't worry, Give it some time it is still early for limas.Limas are also hard to tell when ripe. When I see the first yellow pods I wait a few more days till they start to dry then the bulk of the crop will be ready. The dry I save for seed the rest I shell out to eat. Typically for me it is mid to late July for the first crop of Limas when planted first of May. Rodger

Well, I waited 2 weeks but my harvest was poor. I'll probably not plant the running beans again. They just don't produce as well as bush beans for me here. The pods dry out before they are filled out fat and mature.

If the pods began to form, then that eliminates several possibilities. Pollination is not an issue, nor is there excess nitrogen... unless it was applied after flowering began.

When pods abort, or are poorly filled, my first guess would be water stress, perhaps aggravated by hot weather. If the base of the vines is not mulched, it might be worthwhile to do so, and keep them well watered. There is still a chance that you can get a good crop, perhaps when the weather cools a little.

There is a problem here. I need more information to help you out. First were are you located. There is an 8 in your zone I would think you would have no problem with limas in zone 8. I am still puzzled how you can get limas in June. I have planted in first week of April and not had limas till after the 4th and I am in zone 7b/8a on the border.
Zeedman has some good advice. limas are drought tolerant but they still need water and like nice soft soil. If the ground is hard and covered in grass this could be a problem also.
]You mentioned you will not grow running limas again, have you had success with bush limas?
Are they in full sun or is there shade at some time during the day. And what have you used for fertilizer.

And I have to ask this are they limas? I have some common beans that are diffently daylight sensitive and are planted as a fall crop and the seed on them are brown red and look like lima bean seed. I have a runner bean giving to me called cherokee butterbean and it is a speckeled runner bean. And runners will not set reliable in the heat of summer for me in SC.
A few thoughts Rodger

Need some seeds How much?

Sonny in SWFL. about $12.95 per pound from Vermont Bean.

Here is a link that might be useful: Florida Butter Speckled