Could use of starting spray cause any damage?
I have a 3GM30 Yanmar in a 1998 sailboat which I purchased two years ago. The previous owner acknowledged it had been rebuilt and wasn't always starting quickly. It is getting harder and harder to start sometimes requiring repeated cranking. I have had valves adjusted, compression checked, injectors replaced, fuel filters replaced, and of course fuel line bled. When it does start it runs fine. I have, at the suggestion of a slip neighbor, tried a very small puff of starting fluid, sold in spray can which says ok for diesel and gas engines. It doesn't require much and just a short puff in the air cleaner intake does the trick, and it immediately starts the engine every time on first crank.