Outboard Motor Issues

Hey guys, happy to be among the braintrust!
Having issues with a 40hp Evinrude outboard. Starts up great, runs fine for a lap or so around the lake. Anchor out to swim, 30-45 min and it starts back up but sputters out, quicker with each attempt. Any ideas? Swapped fuel pump and didn’t seem to work. Help!

What year is your Evinrude? Is this a tiller?

It is a 1999 E40PL4EE

Carb bowl floats not working properly and flooding out the engine? Tank cap properly venting? Is it sunken in or bloated?

If you have an external gas tank next time out when you go for a swim disconnect the tank and release the gas pressure by poking the ball with something. Hookup before you’re ready to take off again.

Sputtering may mean different things to you than it does me.

Just had the carb cleaned so I doubt it’s the ball?!
Sputtering as in starts quick, runs strong…then appears to start to hesitate, isles lower, and eventually stalls. Sounds as if it runs out of gas, but that’s not the case.

I know you probably checked this but is the vent on your gas tank open?

Yes sir…loosened it, blew out the mesh just to make sure, loosely put it back.

is the primer bulb staying firm?

Brian G wrote:

is the primer bulb staying firm?

That’s what I’m wondering. I’d just go ahead and swap the fuel lines. Today’s gasoline eats them up. They may look fine from the outside, but they are clogged like an old man’s artery.

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Swapped the fuel lines. Same thing. Changed fuel filter too. Runs great, high rpm, shut it down for about 30-45 min, starts, turns over, sputters out. Sputters out quicker with each attempt. Also noticed that barely any water is coming out of the pee hole, in idle or high rpm…could that be part of the issue?

I think I’d address the low water output thing before I worried too much about the cough and sputtering. Could be a frozen thermostat or it could be the impeller is toast. Running any outboard without a steady stream will not be good.

How about fuel pump on motor ?

Changed out the fuel pump and filter, same result

Who cleaned the carbs? How were they cleaned? New kits or just blown out or soaked or what? Problem began after this cleaning?

Got to address the water situation as Tom stated. Surprising how new water pumps fix most issues for people. Start there, it’s cheap enough.

Looks to be fuel injected from model # you provided.

Cancel my membership to the mechanic forum

Lol exactly…I have a couple motors and didn’t realize til after my “mechanic” dropped it off that he charged me to clean a carb that this one doesn’t have!! So he’s out…that’s why I wanna try and dial this down myself! With limited experience and you guys’ wealth of knowledge!

Something kind of like this happened to my motor. The previous owner put a screw through the control wire harness. First time the motor started up great. The second time I could not keep it running. The problem was the screw nicked 2 wires and would keep the primer engaged. Not sure how this story can help you but thought it might be something to look around. Might not be a screw shorting it out. It could be a problem on the controller side.

Carbed Johnson/Evinrude motors have a red valve on top of the primer. If it’s inline with the primer itself it’s set to auto, which you want, if it’s turned offset which can happen when being worked on it’s set to manual prime which is always on. If yours has something like that worth checking out

Water stream is definitely still #1 issue though. Don’t want to fry that motor, could be as simple as blocked pisser.

Replace the water pump/impeller and any thermostat that might be in there too. Then try it. Running a motor with a bad water flow for cooling will leave the engine god-awful hot. After sitting for 45 minutes hotter than normal fuel can get cooked out of fuel lines and injectors and you can develop air lock in the fuel system which accounts for the sputtering and stalling. There’s a ton of heat under that cowling and poor water flow will just add to the heat factor giving you your headaches.

I would look into the IAC valve,and fuel/air lines under cowl.I am not sure if that EMM on that year motor will store fault codes?

Factory service manual is your best friend.Can save a lot of $$$

Thanks a lot guys! Very helpful!
Tom…that sounds like a comprehensive fix! I’m gonna try and do that, see if we can’t get’r goin!
I’ll keep you posted
Thanks again!

Running the motor for 30 minutes with inadequate cooling water will build up engine heat like crazy. Then, when the engine is shut off that excess heat really seeps out of the engine and into a bazillion electronis gizmos that can be super heat sensitive. Those gizmos are designed to operate at a normal operating temp, not an operating temp that’s excessive and then has no place to go….that cowling is insulated to buffer engine noise but also stops heat from getting out from underneath too. Fuel in lines and other components can heat beyond what is considered normal too and do things that aren’t normal as you’ve discovered.

I think things are running way too hot. Does the outboard start and run like “normal” when the engine is cold? If it does, then I say heat is the culprit and lack of water at the pee hole is the first give-away that the heat may be the issue. There’s a difference between “normal operating temperature” and over-heated and all that electrical garbola can get screwy if its over-heated and may well show itself as a fuel issue when in fact its not.

Iowaboy1…..where is our aircraft mechanic when we have an outboard issue?

This is assuming his overheat alarms are also not working which are pretty simple systems.

I’m all for precautions but doom and gloom seems to only help find issues which aren’t there.

how much battery voltage do you have?

I will give this a shot,if that thing is running as long as you say it is it has to be getting some form of cooling water or it would be seized up by now I would think.
make sure the tell tale hose isnt plugged with leaf cutter beetle eggs and tiny chunks of leaves left for food for the larva,or dirt and sand from running in shallow water.

I will admit I am not real familiar with the injected Evinrudes but it almost sounds like an injector is sticking open when warmed up and flooding the motor.
I would suggest taking it in and having it scanned when its cold to see what the sensors are reading versus when the motor is warmed up good as sensors can change quite a bit when they are failing with different temps.

if and when you decide to take it in,make sure they take it out and run so the issue can be duplicated as the computer may not hold old codes.

keep us posted on whats found out !!