73 50horse merc stalls

[deerkill99]

I have a 73 merc that starts and runs for about 3 to 5 secs then stalls. I have checked the tank and the fuel line, from what I see it looks like it is getting fuel, but not sure. Any help would be appreciated.

[N5XL]

The good thing is that it does start and does run for a few seconds which would rule out any serious problem with the electrical.

Is this the first time this year you've started it up, or have you run it already?

If its coming out of winter storage, if there was any remaining fuel left in the carbs, they will need to be pulled apart and cleaned. I am assuming you've got multiple carbs, but it depends on the exact model number of the engine you've got. Either way, they would be the most logical place to start.

For what its worth, my Merc's have always been more sensitive to stale/varnished fuel than the old OMC's I've got. I'd start at the carbs and go from there.

Dave

[Wgoodrich]

First thing I would check is conditions. When you started this motor was it in the water and in neutral then dies when you put it in gear ? If this is the case suspect compression too low to keep running under load. Take out the spark plugs and test the compression of each cylinder. Compare that answer to the minimum recommended compression pressure per your manufacturer's manual. I suspect the minimum will be 90 pounds per cylinder. If you are below that you sometimes can still run when put in gear if the speed is adjusted. I had one like you discribe and made it last 5 more years doing that. I gave up when the compression measured 50 pounds per cylinder. It was running great on a hose in the yard but when in water it idled fine and sped up with warm up throttle but when put in gear in teh water it died no matter what I did.

If your compression test passes then If you have the carbs I think you do I would hook to the trailer and drive it around a rough road then back home then drain the gas tank and install new gas and oil mixture and try again. Many times one or more of the carbs floats stick shut. The rough road breaks them loose without having to pull the carbs.

If the two above does not help then pull the carbs and have them cleaned, change the spark plug and be sure to have fresh gas and oil in the tank.

Good Luck

Wg