Hey Swarfy
Re the throttle, I’d put a new throttle cable on that same morning but there’d been no sign of sticking. Would the excessive heat from the engine maybe alter the fit of the slide in the body causing it to stick?
Slides sticking “up” when the engine is hot is very common (particularly with A65’s). That is behind my “reply no 4”. Giving the carb a tap can result in an audible click as they drop down. A missing or ineffective insulation spacer is usually the cause, but distorted carb bodies from over tightening is also a common cause, which can be checked on a cold engine of course.
In your case there is an outside chance the engine “conked out” due to overheating with the throttle wide open, which led to the starting issues you described, and probably no piston seizure.
The throttle would indeed have been wide open, trying to get to the top of the hill.
No seizure would be a good outcome, but the only way I’ll actually know for sure is by taking a look inside.
I’ve got a number of things to check first before any drastic exploratory surgery though. Firstly checking fuel flow, as TT suggests.
Just out of curiosity, would it normally be necessary to drop down into 3rd for a steady 2 mile climb? I wouldn’t have said that it was mega steep, and 5 minutes earlier it had pulled nicely in 4th up a steeper, but shorter hill.
In my head, it is starting to point towards a weakening of the mixture caused by a vacuum in the tank, hence running fine until the vacuum becomes too great to allow sufficient fuel for a correct mix.
I might try to test this theory by finding some hills and once it starts struggling undo the fuel cap, see what occurs. Of course it might result in a long walk home.
Thanks as always to all the heads on here.
