1992 3.0 merc stalling after few minutes

Hey guys new to this site,


I have a 1992 3.0 merc, after several years of solid, dependable use my merc is dying. Started about a month ago coming back from fishing noticed the engine sputter and feel like it was going to die" like when you run out of fuel". Brought the rpm down a bit to around 2800 to 3000 and it ran fine the next few minutes to boat launch. Next time out no problem. The next few times out same issue but started doing it more frequently and to the point boat came off plane and I had to just idle for a bit then speed up again. Last time up the lake a few days ago the engine would run great for about 3 minutes then sputter and die" like I ran out of gas". Then I would start it after 30 sec and continue on for 2 min the die again. I finally could do nothing but slowly basically troll up to my destination. Same issue on way down but this time fully died and couldn't start back up. Killed battery trying to start. I thought I smelled a heavy gas smell every time it died so I have tried to swap carbs, my buddy has the same engine and carb so we swapped, that didn't help, it did the same stall thing as before. I have also pulled the fuel water filter searching for bad gas, gas is clean no water. I've also changed the spark plugs and checked the wires. No issue there either. I am starting to loose my mind trying to think of what it may be. Any help would be great and also I've done a lot of reading but can't find a simaler issue

thanks Travc

I'll bet you've got ethanol gas problems. Given time and moisture, the dreaded "White Gook" will form in the tank. (See photo.) This stuff will go right through water separators and filters, end up in the bottom of the carb (where the gas enters the jets) and will not burn.

If this is the case, here's what you'll have to do: Remove every drop of gas out of the tank using a pump and hose stuck in through the filler opening. You have to get it ALL out since it sits on the bottom. Tilt the boat to get one corner lower and keep sucking it out. Next, add a few gallons of fresh gas and repeat the above. Finally, add some gas stabilizer (Startron) with every fill up.

Jeff

PS: You can let that old gas sit overnight, then suck out the top 3/4s of it and use in your car/ truck.

Thanks for the idea fastjeff, I didn't even think of that one. Instead of going through the process of draining the main tank in the hull of the boat which is a major pain to get to, could I just set up a clean gas tank up to the fuel pump with fresh gas and see if the problem persists and if it does or doesn't then do the major t
tank cleaning?

Absolutely!

Jeff