I’m at a loss - Evinrude 40

[jimmbo]

Spraying lol, definitely not pouring out. It looks like it is vaping/misting out of the carbs about 2 inches while running wot when I had the air box off. That along with the pulsing out of the air box made me think it was reeds

Then I suspect your next option is to replace the Reeds. You might have to call some dealers to see if they have any NOS on the shelf. Just don't tell them you have been searching all over the place, as that can raise the Price.
A last Option, and in my opinion a Last Choice, is a set of Boysen Reeds. These are Fiberglass and have a Limited Lifespan. Some people claim another 30hp with them.... but I doubt there is any difference.

 

[Keegan7]

Then I suspect your next option is to replace the Reeds. You might have to call some dealers to see if they have any NOS on the shelf. Just don't tell them you have been searching all over the place, as that can raise the Price.
A last Option, and in my opinion a Last Choice, is a set of Boysen Reeds. These are Fiberglass and have a Limited Lifespan. Some people claim another 30hp with them.... but I doubt there is any difference.

I have a friend who does a lot with 2 stroke scooters about my reeds and he suggested fiberglass reeds as well, but how long are we talking when you refer to limited lifespan? 100 hours? 500 hours? 1000 hours?

I think I’ll go ahead and purchase some reeds once I find some to see if it solves my problems.

Will these work fine? https://chriscarsonmarine.com/product/sport-reed-valves-40-60hp-2-cyl-1970-1999/

 

[racerone]

New set of reeds will fix that 9 out of 10 times.----Good luck with it.

 

[brodmann]

If the motor is a wide open throttle at the beginning of this video and it struggles to get to full RPM's, but finally does, I would suspect either a fuel delivery problem, where you're starving for gas until the fuel pump is able to fill the carburetors, or else a timing issue. When you squeeze the primer bulb, can you "feel" and hear gas going into the carburetors and does the bulb get hard? Do you have a manual to tell you how to sink carbs and set timing?

 

[Keegan7]

If the motor is a wide open throttle at the beginning of this video and it struggles to get to full RPM's, but finally does, I would suspect either a fuel delivery problem, where you're starving for gas until the fuel pump is able to fill the carburetors, or else a timing issue. When you squeeze the primer bulb, can you "feel" and hear gas going into the carburetors and does the bulb get hard? Do you have a manual to tell you how to sink carbs and set timing?

Don’t have a manual, but I’m mechanically inclined enough to know it’s not starving for fuel, nor is it a timing issue. I checked timing while putting the motor under load in the water and it read as it should. I ruled out starving for gas when I used the fuel primer on the ignition while I was wot and it bogged down, so fuel is good. Carb butterflies are set correctly and the line on the cam roller is where it should be, so I think the link and sync is fine. My best guess is reeds because I recently noticed it’s puffing air out of the air box holes, sprays gas out of the carbs at wot, and excessive gas consumption. I’m getting some Monday to see if that fixes it. If you look back I have videos and pictures of most of the stuff I talk about.

 

[brodmann]

Sorry, just re-read your initial post. Yeah Racerone made the right call. 2-stroke motors utilize the compression of the down stroke of the piston to push fuel into the top of the cylinder. If there is any gap in the reed valves, you're starving for fuel. Once RPM's pick up, the pressure is enough to close the reed valves up, but while building up to that point you're struggling for enough fuel.
Good call Racerone!! Again!!

 

[Keegan7]

Sorry, just re-read your initial post. Yeah Racerone made the right call. 2-stroke motors utilize the compression of the down stroke of the piston to push fuel into the top of the cylinder. If there is any gap in the reed valves, you're starving for fuel. Once RPM's pick up, the pressure is enough to close the reed valves up, but while building up to that point you're struggling for enough fuel.
Good call Racerone!! Again!!

Yeah, I don’t know how it would be starving for fuel, but more starving for the entire fuel/air mixture. I used the primer to add fuel while accelerating and all it did was bog the engine, so it’s not just fuel it’s starving for.

 

[Keegan7]

New set of reeds will fix that 9 out of 10 times.----Good luck with it.

I was hoping I wouldn’t have to return to this thread after installing my new Boyesen fiberglass reeds.

Turns out the problem still resides. I know the reeds are installed correctly because it doesn’t run any worse or any better than it did before. What could it possibly be now?

 

[racerone]

And you were really convinced it was the reeds !!-----What trouble shooting are you prepared to do.----Have a fellow driving for 4 hrs for me to have a look at his motor.--2000 model 70 Johnson.------He has guessed at everything and replaced almost all the ignition components ----Wasted lot of effort and spent many beer tokens.---Still no spark.

 

[Keegan7]

And you were really convinced it was the reeds !!-----What trouble shooting are you prepared to do.----Have a fellow driving for 4 hrs for me to have a look at his motor.--2000 model 70 Johnson.------He has guessed at everything and replaced almost all the ignition components ----Wasted lot of effort and spent many beer tokens.---Still no spark.

Yeah, I was very convinced it was the reeds lol. This issue seems so strange to me. I can’t possibly think of what else it could be. Any suggestions?

 

[racerone]

Cheaper to visit a good shop and have them look at it.

 

[Keegan7]

Cheaper to visit a good shop and have them look at it.

I don’t know about cheaper, lol. That’s kind of the whole point of working on it myself.

 

[F_R]

Judging by your picture, you look to be 65-70 years younger than me. That's good. You have a great future ahead of you. Do you have any goals? Enginering maybe?

Back to the motor, I still say there is nothing wrong with it. There's no problem with trying to improve it though.

 

[F_R]

Hm.m.m.., now I got myself thinking. Any chance somebody has been re-engineering that motor? Something like bigger or different carburetors, dinking with the intake/exhaust ports, or something else to make it a go-faster model?

 

[Keegan7]

Hm.m.m.., now I got myself thinking. Any chance somebody has been re-engineering that motor? Something like bigger or different carburetors, dinking with the intake/exhaust ports, or something else to make it a go-faster model?

I’m hearing you out when you say there’s nothing wrong with it, but it just doesn’t seem like a prop, weight, or balance issue. I put my friend in the front, moved battery and gas tank forward - nothing changed. Only thing left to change is the prop, but I don’t think it’s too much for this size motor and the weight of my vessel.

I’m 20 and currently in school for cyber security. I’ll be graduating in the spring. I’ve always liked technology and came to realize that I will always have job security in the tech field. I work on engines, cars, motorcycles, and weld in my spare time.

When I looked inside the crankcase, I didn’t see anything that looked to be ported. The carbs look like everything belongs and nothing is out of place. Doesn’t seem to have any vacuum leaks. New fuel lines all the way to gas tank. New reeds, new power pack, and resistance test on everything I could. I’m at a loss. I’m tempted to just replace the entire ignition system to see what that does.

Please help!!!

 

[airshot]

Check Ebay for a factory service manual, I have found most of mine in there over the years.

 

[atktom]

My problem solve was the spark plug wires were the nylon type and not the copper center wire type. Changed and no more problems with not opening up. That being said, my motor is lot older than yours so don't know if this helps.

 

[Keegan7]

Bump

 

[racerone]

A 40 HP on a 15' boat should sing and move at about 32.5 MPH-----If it does not then some trouble shooting needs to be done.----Just had somebody drive 4 hrs for me to look at a motor.-----Trouble shooting found that one of the " new " parts he put on was defective.----Replaced it with a good used part and he is on his way happy as can be.

 

[Keegan7]

A 40 HP on a 15' boat should sing and move at about 32.5 MPH-----If it does not then some trouble shooting needs to be done.----Just had somebody drive 4 hrs for me to look at a motor.-----Trouble shooting found that one of the " new " parts he put on was defective.----Replaced it with a good used part and he is on his way happy as can be.

I’ve got a charge coil on the way due to mixed results on resistance tests and the leaking insulation from the charge coil. We will see if that does anything.