I generally do not fish on a lake that has a maximum HP limit or limits the use of outboard motors altogether.  If there is a specific lake rule that indicates "electric motors only" does that mean you cannot even launch a craft with an outboard or can you use a boat that has an outboard but simply not use it?  Similar question about lakes with a maximum HP rule of say, 25 hp.  If my boat has a 75 hp motor, can I still launch it and just use the electric bow mount?  Thanks

You need to check local regulations, it varies from state to state, and maybe even by county...

 

In VA as long as I don't use my motor, I'm free to launch in most electric only lakes.

 

Some places it varies by body of water, do yourself a favor and check your specific lake. Some range from no bigger motor, to it must be trimmed up, to it can be in the water just not running.

There's a couple of lakes here in Texas that are electric only. You can use the boat in the lake, but you have to put like a trash bag on the lower unit on the boat to prevent any thing from leaking in the water. 

at Tenoroc we can put it with any boat but can only use electric, some of the lakes in the chain you can idle with the big motor but no faster. 

 

Depends on the local regs.  We have lakes in PA that are electric only, 9.9 max and 20 max.  All of those, you can launch a boat with a bigger motor as long as you don't use it.  We also have some reservoirs that are electric only and forbid gas or gas motors, so if you have an internal tank, you can't launch even if you remove the motor.

It is definitely a matter of local regulations and/or the rules of the lake. I lived on a lake that was electric only and didn't allow a gas motor on the boat at all. I would have to take the motor off every time I fished there. I bought a cart for the motor that made it relatively easy to  do so. 

I regularly fish on electric only lakes and reservoirs here in NJ where I see bass boats with monster motors on the back. As long as they aren't being used it is OK. On the limited horsepower lakes and reservoirs around here (usually under 10 hp) a lot of boaters have a dual setup with a 9.9 on the back along with the big motor. In many cases  they are hooked up so you can operate either from the console. I've seen boats as long as 28 ft on these limited HP lakes using just the 9.9. One of my fishing buddies has 21 ft Lund with a 250  HP motor and a 9.9,  with electric lifts for both motors. They are connected so that they both can be steered from the console and it only takes a few button pushes to switch motors.  That is OK here. It might not be OK where you are. 

There are few places here in Jersey where you have to remove your prop from your motor.

check in advance... I've seen some where you can just be trimmed up and some have denied entry with the outboard on the boat. 

In Indiana it's based on lake size. Anything under 300 acres (I think, may need adjustments) is electric only. Most of these that I've seen it would be difficult if not impossible to launch a glass boat, some very shallow ramps, and some that just about fall into the abyss!