1998 Optimax 135 - Running Problems - bad gas?

All - thanks in advance for the help.

I took my 1998 135 Opti max out today for its maiden run for the year. It ran fine coming off the trailer, and for about 5 mins after that. It seemed like whenever I went to give it throttle, it would bog down.

After a while, it died. Tried to let it sit and re-start but no dice. I raised the motor so the exhaust was out of the water, and about every 10 attempt, it would catch and run until I lowered the engine back into the water. Almost as if the exhaust couldn't handle the pressure.

After a long troll back to the dock, I trailered and tried again. It caught, fire right up, so I attempted to give it throttle only. It ran great for a second, then started coughing some, so I shut down and came home.

Admittedly, I haven't been the best on maintenance. It has been such a great, problem free motor that I have gotten lazy. I can't remember when the last time I changed the plugs. Also, I let about 1/4 tank of gas sit in it over the winter with no stabilizer. Today, I put between 1/4 and 1/2 a tank on top of the old gas, hoping it would mix and be fine.

So, I am wondering what everyone thinks. Bad Gas? If so, do I need to drain the tank and start over?

Re: 1998 Optimax 135 - Running Problems - bad gas?

Did you have any warning lights or warning horns going off during this?

Re: 1998 Optimax 135 - Running Problems - bad gas?

Water in the fuel perhaps???? With an injected motor ALWAYS use a fuel system stabilizer like SeaFoam, StarTron, Stabil, or any of the others.

Re: 1998 Optimax 135 - Running Problems - bad gas?

Gents - thanks for the responses.

No, I was not getting any lights or horns. Just started bogging down. Then hard to restart and when it did, would not take throttle and wouldn't let me trim back down with the exhaust deep in the water.

My gut tells me this is a result of letting it sit all winter with fuel in the system, which lie I said, I know better. It was a cold winter this year, and even though it was garaged, it still sat a long time and got pretty cold.

Is this advice to add stabilizer something I should do now? I have a container of Sta Bil right in front of me, but don't know if I should put it in, or try and drain the gas.

I am also going to head to Bass Pro tomorrow and pick up some new plugs. It had NGVs in it, so will probably put those back in.