How to use Power Tune on EFI ?

[Rusty C.]

Even though I have been using the cocktail on all of my fuel, the previous owner didn't always do as such. I am thinking I may have carbon build up in my Mercury 200 EFI. Regardless if I do or don't have any build up, I want to be sure the engine is performing at its very best. I picked up a can of Power Tune. It says on the can for carburated and EFI engines. It gives instructions on how to use on carburated engines, but not EFI. How do I use this? Remove air box and spray in air intake?

 

[Bob Bourget2]

If you have an EFI, you can't remove the air box, because there isn't one. The best way to use power tune on that engine, is to introduce it through the spark plug holes, let it sit for an hour or so, fire it up and burn it out. An alternative......if you use Sea-Foam in the fuel, there is no need to "power tune". This stuff is takin' care of business internally.

 

[Rusty C.]

THanks Bob.

Something else I've been thinking about. This engine seems to run great, but since I have had it, it has never been very quick responsive when I "put the pedal to the metal" on the hoot foot when taking off coming out of the hole. I press the hot foot all the way down and it is like it is slow getting fuel to the engine. It doesn't jerk you back in other words. I didn't know if that is normal or it should be more responsive like a car.

 

[Bob Bourget2]

What type / kind of prop and what is your max rpm?

 

[Rusty C.]

I am pretty sure it's a trophy 4 blade. When WOT I get 5600-5700 RPMs.

 

[Bob Bourget2]

If you have the 2.5 litre 200, the "correct" prop is crucial to THAT motor's holeshot. I'd really like to see a few more rpm on the top, and the only way to achieve that {if all else is good}, is reduced pitch. Experiment with the PVS plugs, and let the motor spin up a little more coming out of the hole....which means either larger plugs or less of them....

 

[Rusty C.]

I will give that a try Bob! Thanks!

 

[Darren Wilkes]

I too have a 96 200 EFI Mag. Mariner, it is not coming out of the hole. It will only get 3000 rpm and just stand the nose up. I had the ECU rebuilt, replaced a voltage regulator that had some wires heat discolored and had the prop reworked. It was on a 96 Pantera 2 but I traded and put it on a Nitro 898NX. The prop is a Tempest 25" . It doesn't seem to miss just not spool up. I have the PVS plugs out. Motor jacked up as high as possible on a jackplate. I replaced the fuel lines from tank to engine. Have even ran 100 octane aviation fuel through it with seafoam to clean injectors and removed and replaced all filters and screens in the fuel system.

Any suggestions before it gets a Viking funeral?..................I am just hard headed enough that I will keep plugging along and fix it.

 

[Scott Hammer TOXIC]

Do a compression check. Is your WOT speed still there once you get on plane? You are lucky you didn't blow it up running 100 octane. That fuel is for high compression engines which you don't have. It also burns cooler with a higher flashpoint. Put the recommended fuel back in it. Did you check and make sure you are getting full throttle (cable)? If everything checks out then you need to look at a different prop.

 

[Darren Wilkes]

Do a compression check. Is your WOT speed still there once you get on plane? You are lucky you didn't blow it up running 100 octane. That fuel is for high compression engines which you don't have. It also burns cooler with a higher flashpoint. Put the recommended fuel back in it. Did you check and make sure you are getting full throttle (cable)? If everything checks out then you need to look at a different prop.

When it was on the Pantera the top end speed was still there at WOT but took forever to break over to get on plane. Compressions are all near 120 +/_ 5. On the Nitro I cant get it on plane to see about the speed. It has always been very sluggish. Every Pantera I have seen with a 200 hp merc or mariner have this same prop or I would have changed it out earlier. I am planning to borrow some props and do some testing hopefully this weekend but I firmly believe there is some lil something I am overlooking that is killing my low end power. It does not miss and the cable is opening it to the WOT position. The Aviation fuel was ran through to remove varnish and carbon build up. I am running 89 non ethanol and seafoam. I have used the Avgas many times in small doses as a fuel system cleaner. I don't look for performance from it at all.

Can you tell me the initial timing and full advance settings? What rpm should it reach full advance? ect..........

 

[Darren Wilkes]

Would I be better off running lower octane fuel (say 86/87)and adding a stabilizer/ethanol treatment. This is my 13th boat motor and I think it is demon possessed.....lol

 

[Scott Hammer TOXIC]

I don't like to refer to other websites but you need to go to Bass Boat Central and get on the Mercury board and ask Don Weed of European Marine. He is a crackshot mechanic and can make sure you are set up properly. And yes run the octane level your engine calls for.

 

[AirForce]

 

[Darren Wilkes]

Hey there AirForce, I too spent time in Uncle Sugar's Flying Circus ......lol............thanks for serving our great nation.