Issues after Power Tuning and using SeaFoam...

[lucasm01]

I have a 2004 Mercury 115. Did the power tune spray last spring to clean off some of the carbon build up and then used sea foam in my gas tank to help run cleaner gas through her. Ever since I did that my motor seems to lag when i put the throttle down. It seems to idle fine and click into gear fine but once i hammer it, it will sputter a bit before taking off. Once I am on plane, it runs perfect with no hiccups.

Do you think this is caused by the Power Tune i used in the carbs or from using sea foam in the gas? I dont know if something got gummed up in the carbs or if the fuel is running too rich/clean for a 2004 motor?? I would like to try and fix it before bringing it somewhere and spending a couple hundred bucks just to get it diagnosed. Any idea or things to try and fix it would be helpful!

Thanks!

[leonreno]

Using powertune or sea foam can cause the spark plugs to fowl up, I would replace plugs then test again.

It’s also requested that you post your motor’s serial number so we know exactly what motor is being discussed, thanks.

[lucasm01]

I did change the plugs out as i thought that/was hoping that was the issue as well. Still having the same issue. I will get my number up here when i can. Any other thoughts?

[buster502]

how did you use the power tune ???

[lucasm01]

I followed a video that told me to have the motor running and spray the power tune directly into the carbs, going back and forth between the carbs but not allowing the motor to die. After that, i let it rest for a few hours then took it out to the lake to run it and have the carbon burn off.

I know the other way to do it is run it through your fuel system which I did not do. I sprayed it directly.

[leonreno]

Is the gas in the tank fresh? That can cause similar problems.

[EuropeanAM]

If you would, please take a moment to review the Announcements at the top of the Forum, and be sure to provide the Required Information each time you post. Thanks!

Also, exactly what spark plug did you use? Gap? What other maintenance has been performed?

[06 SB]

There were several different Mercury 115s made that year. Each is vastly different and SN is required.

It almost sounds like there is not enough venting in the prop. What prop and size of PVS plugs are you using.

If the motor is an inline 4cyl, it could also be having an issue when the second set of cylinders come online around 1800-2000 RPM.

[buster502]

i done mine a little different,i pulled all the plugs tilted motor all way up and spayed a good amount right on the pistons,let it sit over night put old plugs back in and go the next day and run it kinda hard then put new plugs in,mine jumped 15 lbs on the compression gauge and i had been using a in the gas cleaner but this way really got the carbon cleaned out

[lucasm01]

My boat is in storage now so I will get the serial number soon. I did the power tune a year ago, and Buster, after you describing that, that sounds more like what i did also. I pulled the plugs and let it sit over night and took it out the next day, ran it hard and replaced the plugs. I dont know if soemthing got caught up in the fuel line, or gummed up that would cause a minor fuel blockage??

06 SB, it doesn't feel like a prop spinning issue, i dont run plugs in my prop either. The issue is starting before the prop even starts to spin. Guessing fuel related or possibly a throttle cable issue.