Question for the mechanical geniuses on this page.

My 1997 Evinrude (150) runs great until it runs for 10 minutes or so wide open and then it starts losing power until it dies. Prior to that, it runs fine a low speeds and starts perfectly. Bulb seems to never get very hard at the beginning of the trip but nonetheless, it will still start fine. It’s also hard to re-start after it dies but if I pump the bulb while I restart/turn the key, I can go again just fine (until I go ten minutes or so wide open). It seems to be a fuel issue at top speeds. Is that a bulb issue, fuel pump issue or…? Trying to narrow it down, but I don’t have the expertise.

because you said the bulb never gets very hard, i would say check the fuel pump diaphragms

Thank you sir. That is a very helpful insight. I had those in mind, because it was doing something similar when I first bought it several years ago. It would surge and buck at a certain RPM, but never die. If you backed down the RPM it would go back to normal. But I was hoping that wasn’t the problem since I had the entire pump replaced fairly recently (2 years ago). Must be a common problem with these motors(?). Not indicative of the bulb, I assume?

Man, I don't like it when the motor does that, that can be really bad things in just the beginning. Before you do anything else, if this was mine I would pull all 6 spark plugs and have a look inside each combustion chamber and pay real close attention to the exhaust ports, that will be where bad things start is the exhaust side of the combustion chamber. All looks good, then while you still have the plugs out, do a compression test on each cylinder. You want to see all 6 cylinders within 10% of each other.

Then if all this above is good, would I start elsewhere. Our single biggest issue we have is the fuel. If it's over 45 days old since leaving the refinery, not the station you bought it, I would pump it from the boat and put in the tow truck. I have a 12 volt pump that has long hoses and long wires with big clips I made from stuff I bought at O'REILLY auto.

Once I am back from the lake I get the rest of the fuel I didn't use put in my tow rig, that way each time to the lake it fresh fuel. Now if your using up your fuel regularly enough, you don't worry about this. There is one other issue here with our fuel and that is the ethanol in it. I buy the no alcohol fuel and from a place I know sells plenty so that it is good fresh fuel.

Our 2-stroke motors don't have all the sensors that our motors in our vehicles do. The motors in our vehicles don't run 5000 rpms for lengths of time like we run our outboard motors do either. So we need to pay close attention to the fuel we burn.

Once I know about all this would I proceed to start the checking of the other stuff.

Thank you, sir. My father passed earlier this year and your guidance on fuel and other possibilities sounded almost exactly like him. So, I cannot tell you how much I appreciate your guidance and counsel on this. It brings back good memories.

A quick update: it looks like a clamp on a hose leading to the fuel pump had worked its way down (or was never placed back as it should have been). After I repositioned it, the bulb immediately became hard (unlike on the last trip). I’m hoping this might be a/the answer. But I will follow your advice and let you know! Thanks again!!

Yes sir, one thing these motors are really bad about is they will suck air if any place possible, dang I hope that is all it is man, that will be easy fix. Even the air getting suckered into the fuel system can kill a powerhead if left sucking raw air.

I had a 1996 Johnson.. same motor really. I fought those same issues till I found the right mechanic! He recommended that we remove the VRO and install a dual pump fuel pump system on the motor. It’s way cheaper than a new VRO but you do have to pre mix your fuel. I never had another issue. Motor ran awesome until the day I sold it. Several years later. I was told everything from Heat soak, air leak in the fuel system, bad VRO which I spent the 550.00 to buy that didn’t fix it! Power pack, Stator, new fuel lines still did it until the VRO was gone. Also I never had to pump the fuel bulb again. It stayed firm after that. That was my experience.

Really interested in the dual pump fuel pump fix. It no longer has the oil mixing with gas (former owner modified not sure what he did) but it looks like the original type of fuel (VRO?)pump is still on there. I’ve been mixing the oil with the gas from day one. Everyone whose seen it says that was a really good mod. I looked up the replacement pump based on what it looks like and like you said, it was like $500. Do you think Johnson mechanics know the part and can do the “dual pump” change pretty easily/economically? Or do I need to find a “good one” as you found.

That last part is really good to know. Thank you. I would have never known that it threatened the powerhead. If it happens when I test it this weekend…off to the shop it goes!!

I like to premix my oil in the gas, way more than I like the oil in its separate tank. This time of year when it's really cold out, that oil is really hard to pump from it's tank to inject it.

Sounds like your motor already has the mod done, you have to by-pass the no oil warning, if it wasn't you would have a horn going and your ignition would be cutting out. It's a good mod for the right motors.

Thank you all for your input and advice. With all the negativity nowadays, selfless people like y’all remind me of how special a group of fishermen—even strangers—really are. Thanks again!
I’ll give you an update (hopefully this weekend).

omc (evinrude/johnson)had a replacement pump that did no pump oil. looks just like original vro. nothing wrong with it you just have to mix oil with gasoline. check all fuel lines if stiff just need to replace them
including bulb.

I guess I'm one of the few that is still running the old style VRO pump on mine. I hate having to mix the oil and gas. I just always replace mine every 10 years or 300 hours regardless of whether it still works. My VRO is due for replacement next year.

Your bulb is never going to be hard when running, only when you first pump it up to fill the carburetors. After that, fuel just flows through it(unpressurized) as the fuel pump is pulling fuel from the tanks. I would say your problem is one of four things: 1. bad fuel pump 2. Bad fuel lines (inside of fuel line has collapsed and is restricting flow) 3. Debris on fuel pickup tube screen 4. Gas tank not venting properly.

And yes, the loose clamp on the fuel line could possibly fix it also. I hope that is the case for you