Problem with 1991 Johnson Evinrude 40hp? Fuel Pump?

STOP running the motor until you've rebuilt the carbs.

Holding the key in activates the primer ("choke") solenoid, which on that motor allows fuel to drain from the carb bowls into the cylinders (to enrichen the mixture for cold starting).

When the fuel pump wears out, pushing the key in has no effect, because then the carbs have no fuel in them.

What's happening is, you've got an obstruction in a carb jet, caused either by a tiny bit of debris that got past the fuel filter, or else varnish from evaporating gasoline.

When you run the engine with clogged jets, it doesn't get enough lubrication.

The solution:

Remove carbs, disassemble, soak overnight in carb cleaner, blow out all passages with compressed air (or aerosol carb cleaner), reassemble with new carb kits, reinstall, link & sync, adjust mixture screws.

Don't be intimitated by your carburetors, they're really quite simple devices.

Evinrude Fuel Pump

If you hold the key in that is putting the choke in. So you probably have a air leak or fuel restriction somewhere. Start with the basics. Flush the tank and refill with clean fresh fuel (premix if needed), Make sure air vent is open on tank. Make sure fuel pickup in tank is not blocked, make sure fuel line clips are sound and any 'o' rings are not cracked, ensure no loose or cracked hoses, including the primer bulb. Check all lines and inline filters in the engine cowling are sound. Remove fuel pump side cover (should be one knurled screw with a slot) check filter, withdraw diaphragm and examine for pinholes or splits. Replace any and all suspect parts as you find them - no exceptions. If some thing leaks fuel it also can suck air bubbles.

If the problem persists you have to look into the carby, remove carby, take off the bowl and check for grot or snot. Blow out jets with compressed air, these are very simple setups and a rebuild kit is cheap. Reassemble with new gaskets and soft sealant to prevent any possible air leaks and try again. There isn't much after that actually.

Good luck

Edit,

Sounds like JTexas is onto it.

Evinrude 40 Hp

Sounds like a fuel issue.

First off, make sure you have good clean fresh fuel that your using for your engine.

If you do, you have to do some carb work. I would avoid using carb cleaner because it removes the protective corrosion coating on them. Personally, I use a parts cleaner, but you likely do not have one, so I would honestly just use hot soapy water with a good brush. Then rinse with hot water and make sure you use compressed air to blow out everything completely dry. Make sure your float is set to the correct level.

And I'll say this again, be 100% positive you are using good fuel. The ethanol in fuel these days is an absolute nightmare for outboard engines. I have done more carb work as a marine engine technician than you can imagine.

These outboards are real sensitive to air/fuel mix. Agree with cleaning the carbs. But the Primer solenoid (which is activated when you push the key in) has a gasket that seals the manifold piece to the solenoid. Air leaking into their will make it real hard to start and idle like crap. If your going to replace that gasket take care in removing the gas lines from the solenoid. If you break the plastic pieces the gas lines go into you buy the whole solenoid ($100.00) rather than just the gasket ($5.00)

befor you tear your carb off just look at the fuel filter first, either in the carb or befor the carb. might just be that simple! happens all the time

I had a matching project. purely replace the gasoline pump motor in basic terms, no longer the entire factor. purely the motor....approximately $80-$one hundred twenty. relies upon the place you bypass and who you're. I have been given mine from Napa (no longer advertising) and that they base your cost in keeping with how commonly you are available. The extra you come interior the extra decrease priced it extremely is for you. yet i do no longer are available commonly, so it fee me extra.

sounds like fuel problem in the carb. first you should check the spark plugs and make sure they are not fouled. sometimes its as easy as that.

Yep! PARD! jtexas knows his stuff....... Regards RCW