Canopus,
You have just confirmed what I have been banging on about ,without all the GIZMOS you worked out what the problem was, if you had had all these extras on board, which I assume you had not, it would have taken you so much longer to find out what wasn't operating properly.
This is why I say to Newcomers get your steam plants up and running and then if you wish get all the extras once you have gained the experience of running a steam plant.
I have a steam tug CERVIA which has a burner made from a plumbers blow lamp head fixed with a swan neck to a gas tank and can get about 4 hrs running time with this and a boiler feed pump.
The boat weighs 35 lbs just like yours, this boat is 40 years old and started out with an electric drive , was converted 20 years ago to steam and to date have never used any of the boiler and gas control extras.
The D10 in the background is the new engine ready to be installed once the feed pump has been finished, with the original 10V in the back ground.



Thank's for sharing.
George.