Carburetor problem?

I have a 1946 Norwegian inboard boat with a Swedish 2-cylinder, 6 hp inboard engine. The engine was replaced in 1993 with a new engine that’s essentially the same design as the original from 1946. Last summer I had increasing trouble with the engine, starting with it needing more choke than normal to keep from stalling at idle. By the end of the summer, as I was cruising in to my marina (at her normal, brisk 3 kt cruising speed), the engine started needing more and more choke to keep running. Also whenever we encountered any wake that caused significant side-to-side rocking, the engine would sputter and almost stall.

My mechanic thinks the carburetor needs to be rebuilt or replaced, but I have trouble believing an engine that only has a maximum of 400 hours running time would need that (and it looks like it would cost at least $1000).

Anyone have any better ideas?

I would have to ask if gasoline containing ethanol was ever used in the engine? Older fuel systems can’t tolerate gasoline containing any ethanol.

If the choke had to be used in order to prevent the engine from stalling, it means the engine was leaning out or not getting enough fuel. So it could be a carburator problem.


Marine engine fuel systems are notorious for having problems…It’s been 18 years since this engine was installed?? YES, the carburetor is LONG overdue to be dissembled and cleaned…

$1000 to service the carb??? Maybe it’s time to install a nice little 8- 10hp Yanmar Diesel and stop fighting equipment that belongs in a museum…

Or learn how to remove, dissemble and clean your carburetor yourself…A 1946 design will be very simple and straightforward…