I have a 94 Mariner 150, fuel injected. Other than a few obvious things in the past, the motor has run flawlessly for the 2 years that I have owned it. This past Wednesday I hit Lewisville after work and it started up just fine on the trailer. After about 30 seconds or so, when I was idling to the dock, the motor just started dying out, losing rpms gradually until it just quit. I started it and gave it a little gas in neutral and it fired right up. I put it back in neutral and about 10 seconds later it started losing rpms again and choked out. I couldn't get it started for a few tries so I just used the trolling motor to get my partner at the dock. We trolled past the no wake zone and I was able to get it started after I pumped the primer bulb until it was hard, but still had to have the throttle all the way down. It stayed running but I had to keep it at 4000 rpms.

After about 2 minutes of sitting there, I kicked it in gear and started going about 30mph (was trying to keep the rpms up) in circles in case it died again. It ran, but I could feel the motor bogging down every 10 seconds or so, almost like it was running out of fuel. After about 10 minutes or so of driving it finally smoothed up and ran perfectly. For the rest of the trip the motor fired up immediately and idled perfectly.

I haven't changed the plugs in the two years I've owned it and I am going to do that today. I'm just wondering if there is something else I need to look at? Maybe put some of that fuel cleaner in tank or something? I have noticed that for the past 6 months or so, it was a little hard to start initially unless I just gave it a little gas, then it would fire right up. I just figured that was due to really old spark plugs but I don't know much.

Sounds right, new plugs and run Sea-Foam through the tank (available at most auto parts stores).

I think two ounces per 10 gallons of fuel (double check me on the directions)

If you've been running it that long with known bad spark plugs, you might want to consider a de-carb procedure like the one described here.

I would also replace your primer bulb. The check valve may be coming loose. I had those same symptoms one time and that was the problem.
Kenny

i have a fuel filter on my motor changed it out and does better