View Full Version : mercury 240 efi engine cleaner?

12-14-09, 06:50 PM
Has anyone run the 100 hr "mercury precision Power tune engine cleaner" treatment on the mercury 240 efi?

The picture on line looks like a spray can - what's the best way to access the throttle body to spray this stuff in?

Any experiences or tips?

12-14-09, 10:41 PM
Haven't run the quick clean through the engine, but to access the throttle body just pull the plastic cover off the top of the engine. It's at the top of the air plenum right at the front.


12-27-09, 12:39 PM
I have run the quick clean treatment annually as part of winterization procedure.

03-25-10, 02:07 AM
I remove the spark plugs and spray Seafoam cleaner in each cylinder and turn the flywheel to spread the stuff around. I leave it in there for 24 hours. Install an old set of spark plugs and run the engine until the smoke stops. If you haven't done this before make sure to put something down on the ground near the exhausts becuase a whole bunch of black crap is going to come out of the engine and stain the driveway. This will make a huge amount of smoke so do it after dark with a new moon. It will also smoke like crazy the first time you take it to the lake so start it at home first before you go.

don't sink
03-25-10, 09:24 PM
Seafoam works wonders! I used it on my last boat as a quick carb cleaning treatment. As John said- it smokes like a nuclear bomb when you restart the motor! Almost comical! Make sure there aren't any small animals or birds around because they are all going to be crosseyed when the plume hits.:ack:

03-26-10, 02:03 AM
The Seafoam stuff seemed to work pretty good the first time I used it. A few years later I had to take the heads off of the engine to replace the gasket o-rings. I noticed that the heads of the pistons were completely coated in baked-on carbon. I thought I would just use some Seaform to clean it up but nothing would come off. That's when I decided Seaform is good but not super great. I did some Google research and ended up finding out that Easy-Off oven cleaner was good for getting baked-on carbon off. Of course that only works if the engine is apart. It did work good though.

I then read about another product sold at lawn mower stores that sell STIHL 2-cycle power gardening tools. They use a chemical called EDTA that I'm guessing works better than Seaform. The technicians use it to tune-up the 2-cycle tools. You can use it like Seaform. They sell it in 8 0z bottles for under $5. I believe it will desolve the carbon better than Seafoam. I would still let it sit 24-hours to do its thing. I'm not sure how to get it to the valve area though. I shoot Seaform in through the spark plug holes. It might reach the valves but I'm not sure.