Stalling Problem 1989 Mercruiser 260

"I have been using a 1989 Sear

"I have been using a 1989 Searay with a Mercruiser 260 engine to salmon fish for the past three years.

Last year the engine started stalling began stalling while I was fishing. I have had the carburator rebuilt, replaced the plugs, points and condensor. The engine runs well when cold but starts to run poorly and then stalls after about an hour.

Any ideas/help would be greatly appreciated."

"First, I just have to ask why

"First, I just have to ask why an 89 model has a points ignition system?

These things come to mind as to what to check.
The coil could be heating & failing then works after cooling down. The control module could have a problem.
Also the fuel pump could be getting weak or bad blocked fuel pick up in the tank, blocked fuel tank vent.
Fuel filters changed? (doubt it's any of the fuel system if it runs well at higher speeds)

Idle mixture adjustment.
Leaking carb base or intake gaskets after warm up.

Have you checked that the engine is not running hot after long periods at idle?

Just a few thoughts."