40hp Evinrude starved for fuel

Hi all,
I did a search and could not find the a similar situation but then again I'm not sure the exact system that's failing on my outboard. The motor is a 1993 Evinrude 40 hp (TE40ELETB). The motor will start and idle with out any problems but when trying to increase the motor past 1800 RPMS with WOT it just bogs down and wont budge past 1800. The motor will never die and decreasing the throttle to try again repeats the same process over and over. Through experimentation I learned that while at WOT and the motor bogging down if I press the key in to choke it, the motor roars to life and will quickly accelerate and increase speed and RPMs. If I continue to press the electric choke in every 1-2 seconds I can maintain the speed and RPM's but as soon as I stop the motor bogs back down to its sluggish 1800 RPMs while still at WOT. Knowing that the motor is starved for fuel, I had a passenger pump the fuel line primer while at WOT and there was no change in the performance as it continued to bog down. Any suggestions or help to pin point down what I should start replacing or cleaning?

Thanks,
Matt

Sounds like the fuel pump is going bad. I had 2 of them go bad on my 99 Johnson 40hp and had to rebuild it with one of the kits. The ethanol eats up the diaphragm. Double check all you fuel line connections to make sure air isn't getting in. If an O ring goes bad it can let air get sucked in which will cause it to act like that as well.

You are correct in that it is starved for fuel. And if pumping the primer bulb did not help then you can pretty much rule out a bad fuel pump, assuming the bulb was hard while he was pumping it. If it remained soft while it was being pumped and you didn't see any increase in performance then you could have an air leak in your fuel line somewhere, or clogged fuel pickup hose or something along those lines.

I'd start at the fuel pump just to check the built in screen to make sure it isn't clogged since it should be easily accessible. Then move to the carb and check your float, fuel needle valve, and high speed jet. Sounds to me like you just have a clogged jet or sticking needle valve. How old are your fuel lines? If they are more than a few years old I would change them in the process and also flush your tank if you use a portable one. I like to add a clear inline fuel filter to my motors between the fuel pump and carb so that I can use it as a visual check to see that fuel is at least being adequately delivered to the carb.

sounds like the main (high speed like wmk suggests) jet in the carb is plugged to me

once you choke it you add extra gas that main is not providing, causing it to accelerate.

perchjerker said:

sounds like the main (high speed like wmk suggests) jet in the carb is plugged to me

once you choke it you add extra gas that main is not providing, causing it to accelerate.

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I'm with them high speed jets plugged. Had the same thing happen on the same motor

Another thing to check is your fuel hoses. The inner walls of them may have collapsed from deterioration and particles may have plugged your jets. I have seen fuel hoses that looked excellent on the outside and awful on the inside. I have even seen bubbles form from the separation of the inner wall of fuel hoses that will block the flow of fuel through them.

Lots of good ideas guys here! Thanks for all the inputs, I'm definitely going to inspect my fuel delivery from top to bottom and replace anything that looks suspect. The high jet and any adjustments will take some googling and videos to figure out but I dont think it will be hard. I'll report back with some more information and pictures of what I find.

Classic symptom of clogged main jets. I wouldn't adjust anything till I cleaned the mains u may screw stuff up

sdm111 said:

Classic symptom of clogged main jets. I wouldn't adjust anything till I cleaned the mains u may screw stuff up

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My thoughts exactly. . Start with a new fuel hose (may be collapsed inside ) and then move onto cleaning the main jet and setting the float level.

GYPSY400

I had a piece of rtv in my main jet on my johnson 48 spl, same symptom as yours. One of the nuts holding a carb on was loose too.
If yours is like mine, it is pretty easy to remove the carbs and clean / check them both. Although I think you can check main jets some without removing carbs.
Tim

https://imgur.com/a/64yC0

I removed the carbs last night in preparation of my rebuild kits coming in the mail and in doing so I broke one of the brass fittings identified with the arrows on the upper carb. Can anyone help me identify what it is so I can work on getting a new one? I'll be having some help me with the rebuild that is more experienced but I wanted to correct this part before we started.

It looks like the carb inlet from your fuel enrichment valve. It's what you probably have in place of a mechanical choke plate.

I'm not sure how those attach though. Maybe it just threads in and you can replace it.

wmk0002 said:

It looks like the carb inlet from your fuel enrichment valve. It's what you probably have in place of a mechanical choke plate.

I'm not sure how those attach though. Maybe it just threads in and you can replace it.

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I would agree. You can follow the line to see where it connects on the motor to tell for sure.

How to replace it? Not sure about that. It may have to be drilled out and a new one inserted. I am not sure.

Not sure if they are repairable or not. I kind of doubt it

perchjerker said:

wmk0002 said:

It looks like the carb inlet from your fuel enrichment valve. It's what you probably have in place of a mechanical choke plate.

I'm not sure how those attach though. Maybe it just threads in and you can replace it.

Click to expand...

I would agree. You can follow the line to see where it connects on the motor to tell for sure.

How to replace it? Not sure about that. It may have to be drilled out and a new one inserted. I am not sure.

Not sure if they are repairable or not. I kind of doubt it

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I tend to agree that they are probably not repairable (by the manufacturer's standards), however, I'm sure something can be done to make it work. The fuel enrichment valve/choke is not going to create a lot of pressure nor be delivering fuel except for when the key is pushed in so as long as you can get it to not blow fuel all over the place when you choke it, it will be good. You may be able to get by with having the choke hooked up to just one carb and that being enough to provide cold starts.

wmk0002 said:

perchjerker said:

wmk0002 said:

It looks like the carb inlet from your fuel enrichment valve. It's what you probably have in place of a mechanical choke plate.

I'm not sure how those attach though. Maybe it just threads in and you can replace it.

Click to expand...

I would agree. You can follow the line to see where it connects on the motor to tell for sure.

How to replace it? Not sure about that. It may have to be drilled out and a new one inserted. I am not sure.

Not sure if they are repairable or not. I kind of doubt it

Click to expand...

I tend to agree that they are probably not repairable (by the manufacturer's standards), however, I'm sure something can be done to make it work. The fuel enrichment valve/choke is not going to create a lot of pressure nor be delivering fuel except for when the key is pushed in so as long as you can get it to not blow fuel all over the place when you choke it, it will be good. You may be able to get by with having the choke hooked up to just one carb and that being enough to provide cold starts.

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I agree. You may be able to plug that port and possibly even drill out the remaining one to compensate.

I have the same setup on my 200 Johnson. I have been told those jets are just too small to begin with. I was having cold start problems and found out that the fix was either drilling them out or pumping the bulb to pressurize the system, hold the key in to prime it, and repeat this 3-4 times so enough fuel got into the engine to make it light up.

After doing that it starts a lot better. Maybe you could do something similar if you did have to live without that jet.

Barb for the primer solenoid. No worries they just press in and aren't too bad to press out not sure how hard it will be to find a new one though.

I have the exact same motor with the exact same problem. I got this motor second hand and I replaced the fuel lines, spark plugs and foot oil. Fired it up and it's ran like a top for about a month now but, the other night while running at speed it started loosing running and gaining power. I pulled the spark plugs and burned off the extra gas and oil and it ran fine for about 30 minutes and it done it again. Burning the plugs off fixes the problem but, there's something more going on. I'm taking it to a marine mechanic hopefully this week and having it fixed. I will let you know what he finds.

I run only 100% gas with a 50:1 Quick silver oil mixture.

To check for leaks in the fuel line I closed the air vent and ran it until it cause a vacuum.

I've also ran a can of Sea foam through it per the directions for cleaning.



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Usually 2strokes foul plugs either from mix too rich, putting around 2strokes like to be tached out or cracked reeds. Clogged exhaust too but unlikely on marine outboard. If you run it hard then I'd suspect reeds