Well, I see you have a Morgan.
I am guessing that it is diesel powered and gasoline is a second source of power.
If your gasoline is much over six weeks old it is probably weak and may be causing your idling problem.
Fresh gasoline may be the cure for your problem.
A few years ago there was a discussion about alcohol in gasoline in Florida.
As I remember the alcohol content was as high as 15 to 20%.
Percentages as high as these would violate most of the manufacturers warranties or outboard engines.
You don't really seem to have a dirty problem.
Some things you can try are fresh gas, Seafoam, Stabil or just add two stroke oil at a rate of a hundred to one.
Why two stroke oil, because I have never seen a two-stroke metal gas tank that was rusted nor carburetors that were badly fouled.
I always fill my Mac gas tank(which holds 7 1/2 gallons) whenever I take it out and sometimes I will return 7 gallons.
I use is premix in everything, the tow truck, a lawnmower, the leaf blower, a power washer and they all run fine and don't foul the spark plugs.
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
I am not a prejudice racist sexist bigot. I just hate stupid people.