Due to work and lake levels I haven't been to the lake in 2 years. I took the boat out a few weeks ago, put 5 gallons of fresh gas in, the motor would start but would not get up to speed. Is there any thing I can put in the gas to bring it back to life?

if your boat has been setting for 2 yrs it will have more problems than dead watery fuel.

Nothing will help old gas.

As solid advice after the fact: Never do that again. That rig should have gone to a shop without ever turning the engine over. It would have been best to let a mechanic "revive" the engine after sitting for that length of time. The cylinders would have been oiled before cranking, impeller changed, old gas purged, fuel filter changed, etc. Your injectors or jets probably clogged with tacky residue left when the old gas eventually evaporated. Not getting up to speed is probably due to carb/injector clogging, not the old gas specifically. You'll probably need a fuel system service job for your mistake of improper storage.

You should not run any more of that gas, and you should get it to a mechanic before you try to run it again. Get the old gas out, or pay to have someone do so. I used an after-market fuel pump I happened to have. Some boats can be siphoned depending on the tank design. You can't use the fuel supply line to do this because of the anti-siphon valve. (It won't siphon unless you've removed the ball and spring.) I burned off old fuel at 2 gal. per tank in an old truck I have. You may need to pay to get rid of it. You'll also have a mechanic's bill, but it will be money well spent in my opinion.

I also would not run that engine again until the impeller gets changed. The old one is likely set hard as a rock. If it disintegrates at high RPM you're going to have a huge/unpleasant repair bill.

my question would be if had a half gal milk that was old would you put new milk in it and drink the milk

where are you located

North Fort Worth

See a mechanic now. Don't run it anymore

drain that gas, replace water pump/impellar, 2 years is a long time to sit, maybe some seafoam or similar fuel system cleaner, pull a plug and inspect it, pull a carb and inspect it,

that being said, take it to a mechanic.....you may have screwed the pooch this time amigo

I have 200 Merc EFI. Gas was at least 2 years old.

Had it drained and it ran fine

RedRanger, you had an EFI, so no tiny carb parts to gum up as the old gas evaporated. The OP didn't say what motor he had; he might not be as lucky. My mechanic buddy told me not to even turn the key on mine - let him have it to revive. (He didn't say that to make $ as he charged me $0 for the work he did.)