I have a Johnson 25 HP out bord ..it runs fine but when I turn it off fuel flows out air intake and foods it . pull plugs clean put back in and away it gos to I shut it off agen

Anti afterfire (carb fuel) solenoid is suspect. If it has a removable plunger take it out to test if problem goes away. Else snip off the plunger with a pair of side cutters.

The only caveat with this test method is if the magneto kill circuit is not functional you'll need to choke out the air intake or pull the spark plug wires to stop engine.

surges or cuts out, have you check the fuel rail line next to the intake under hood make sure its getting gas and no air or dirt in the fuel line when you locate the fuel rail, there is a black cap that looks like a tire valve stem cap, get a flat tip screwdriver and gently press on the v alve to see if fuel comes thru, when it does let some run into a big gulp cup, to get clean flow, put cap back on, when you finish, add a bottle of heat, timing or cat convertor could be plugged after the fact, need really more details but there is a few tixers

Could be damp has found its way into ignition or fuel system.

I suggest beginning by checking the spark plug and then checking for a nice fat blue spark by laying the plug on a metal part of the engine and pulling the starter.
If all seems ok refit the plug and verify it by removing the air cleaner and briefly using an ether spray into the air intake. If the ignition and timing and suchlike is fine the engine will fire and briefly run. If this is the case the fault is probably in the fuel system.
Small engines have small fuel passages and so require a greater level of care than other engines...

The ingress of tiny droplets of water is almost impossible to avoid in this application and the presence of them is not always a problem when the machine is hot and running but even a pin-head sized water drop tends to be a big problem when cold.
I suggest you check the choke or strangler operation and if that is ok proceed to very carefully drain the fuel tank and check for the presence of water. If any is found the entire system should be thoroughly cleaned.

Plugged carburetor jets.

are you sure you don"t have a possible ignition spark control problem? These control modules have a tendency to become more erratic acting the older they get.If your vehicle is a 98 and if you never had the ignition control module replaced, i would really look in that direction. The problem with is that sometimes they work fine, but then when they get warmed up they start to misfire, until they quit working all together. If the module is over 10-12 years old i would replace it. There"s really not any reliable way to check them because they are electronic and whats happens is the start to short out internally.

The engine is starved for fuel. Check fuel flow. Possibly a dirty fuel filter someplace in the line or the regulator has low flow.

You can verify this by putting an UNLIGHTED Bernz propane torch into the intake. If that improves it, then low fuel flow is the culprit.

Fuel filters for propane are very fine and can plug up easily. I am not sure where yours are, however I would check at the inout of the regulator for one there for sure.

try putting a fuw drops of oil into each pot then try starting her up,,if the pistons and rings are dry you wont have much compreshion it normaly works just fine after starting up, but it will smoke at first till the oil has burnt away also if you can do a compreshion test on the engine if there is rust on the velve seats that will stop it running from poor compreshion

It sounds like your motor is starving for fuel. At an idle, you have adequate flow to keep the engine running. When you call for more fuel...you sputter and quit. Could be a clogged filter or trash in the line or in a jet. Yes you will have some air in the bulb, but not a great deal. You could be sucking air at a hose connection (loosing some prime)...try this, start the engine and slowly accererate, have someone pump the bulb as you accelerate, see if the engine works properly while doing this test.

Sounds like and injector problem to me. If it was a 2 stroke I'd tell you to pull the carbs and clean them ,but EFI is a whole different story. Most certaintly a fuel problem, most likely injector related, you'll most likely need to go see a marine mechanic with the proper equipment to analyze, rather than start replacing parts you may not need.

Let it dry out a day or so, perhaps in the sun or a warm place. Try again. If it still won't start, try to find a fuel line or fuel jet and inject some compressed air in to blow it out a bit. Good Luck!