Re: Evinrude 25...
Hi 2m. Just an amateur suggestion for you. I just recently revived an old outboard and 2 atv motors. All were 2 cycle and all had been sitting outdoors with un-stabilized fuel in them for a long time (between 1 and 4 yrs, depending on who you ask.)
I pulled and tore down the carbs on all three, and found them all to be in decent shape. I replaced the plugs on all three. Most importantly I drained the old fuel from all three and replaced with fresh. Even with that, the OB and one of the quad motors required tons of cranking to get them firing. They would pop, smoke a bit, then nothing for 15-30 seconds of continuous cranking. But with liberal throttle and patience, they all started running. One smoked like my grandpa's pipe for a while, but they're all good now.
Point being: the real problem was the old fuel throughout the system on a cold cold start. I can recommend doing a full maintenance checkup (found a cracked air intake box on one quad, a bit of sludge in carb of the other, and worn impeller and points in the OB) but if you're confident in the motor's condition, it's running status within a year or so, just try cranking it for a while and play with the choke and throttle.
If you're unsure about the impeller, REPLACE IT.
Drain old fuel tank, fuel lines, and carb if you can and replace with fresh fuel (From pump within a few weeks, not the can of gas for your lawn mower that's been sitting in the shed for 2 years.) Then see if you can make that cough a burp then a coughing fit. Might clear itself up.
If not, take it to a mechanic or spend a few bucks on a repair manual, a few hours on this site, and roll your sleeves up and join the masses of us who didn't know what an outboard was until we spent 300 hours scratching our heads and hitting the thing with sticks before we got 'em running. For a while.
