I am always doing that which I can not do, in order that I may learn how to do it.Tonight we persevered with the hunt for the elusive idle. And tonight we found success!
My patient friend and fellow enthusiast brought over three-quarters of his own engine from his (smooth-running) beach buggy so that we could swap out the parts one by one and find the problem. And it turned out to be the manifold, specifically an additional outlet pipe supposedly meant to operate part of an automatic gearbox. Which I have never had. But this pipe presumably went somewhere at one time, now just went forward to towards the front of the bus and stopped, open-ended. Good grief!
Not only have we seen this this pipe before but we have carefully reconnected it without question on each of the times that we have checked, tested, even removed the engine completely! Amazing that we simply never wondered where it went nor what it could used for. So chopped the tip off the handle of my wooden spoon, bunged it into the end of the pipe and clamped it tightly.
Surprise surprise, the engine immediately settled into a smooth idle after re-starting and easily maintains the idle whether hot or cold. Now that it is not gulping great, uncontrolled lumps of air it seems to be working beautifully. A trip around the block shows that she runs with a lot of power, considering the 44 year age and the all the new weight she carries around the middle.
Whew, a struggle taking many months is finally over. Time to move on to new challenges.
Thanks for the visit :)