5 hp Yamaha outboard stalls at idle

[GPSocal]

Landon

Do a google search for Yamaha. Their website will be helpful and may have an owner's manual available.

Good luck

[GrahamHO]

Originally Posted by landonshaw

I have a 2013 or 14 5hp Yamaha outboard. It was running fine, no problems. Last week a lot of rain, dinghy got full and the gas tank flipped over getting water in it. Someone righted the tank so I did not know. Started the engine, it ran for a bit then stopped. I realized what happened so took the engine home.
I took off the carberator but was able to leave th file line and throttle wire attached. Emptied the bowl and pulled the 2 jets. Cleaned everything with carb spray and put back together. Put a new plug in and cleared the fuel line of fuel up past the filter to the carb. Got new gas.
Starte the engine, it started onto second pull and runs well except for idle, it stops.

Took the engine back home repeated cleaning the carb and all fuel line and needle, jets, everything. Jets are clean, all of the holes are clear. Put the engine back on the dinghy, starts on second pull. Still will not idle, it stops. I ran the dinghy for over 2 miles and at full throttle it runs smooth. Go to idle, it stops.

Anyone know How can I get a manual for setting the carberator?

Any suggestions? Thanks. s/v Aloisius. Dave


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There will be an idle mixture screw usually with a little spring around it. Not the idle speed adjustment. Screw it all the way in gently until it stops. Then wind it out about 2 turns. That should allow it to idle. Then you make it idle better by a combination of adjusting the idle speed and idle mixture.

[a64pilot]

Being lean at idle won't hurt the motor, just obnoxious.
Being lean at high power can hurt the motor. I was thinking four stroke, but it's a two stroke?
Four stroke, I doubt you can access the idle mixture screw, they are usually covered. I'm assuming that is a pollution control thing.
I assume where you can buy two strokes, maybe they don't have to meet emissions standards and you may well can access the mixture screw.

[Philsboat]

Originally Posted by landonshaw

I have a 2013 or 14 5hp Yamaha outboard. It was running fine, no problems. Last week a lot of rain, dinghy got full and the gas tank flipped over getting water in it. Someone righted the tank so I did not know. Started the engine, it ran for a bit then stopped. I realized what happened so took the engine home.
I took off the carberator but was able to leave th file line and throttle wire attached. Emptied the bowl and pulled the 2 jets. Cleaned everything with carb spray and put back together. Put a new plug in and cleared the fuel line of fuel up past the filter to the carb. Got new gas.
Starte the engine, it started onto second pull and runs well except for idle, it stops.

Took the engine back home repeated cleaning the carb and all fuel line and needle, jets, everything. Jets are clean, all of the holes are clear. Put the engine back on the dinghy, starts on second pull. Still will not idle, it stops. I ran the dinghy for over 2 miles and at full throttle it runs smooth. Go to idle, it stops.

Anyone know How can I get a manual for setting the carberator?

Any suggestions? Thanks. s/v Aloisius. Dave


Sent from my iPad using Cruisers Sailing Forum

The fuel pump diaphragm might be perforated,causing
Fuel to be sucked into the base bypassing the carb.To prove it out,squeeze the bulb while th engine is running.If the engine stalls replace the diaphragm.

[GrahamHO]

Originally Posted by a64pilot

Being lean at idle won't hurt the motor, just obnoxious.
Being lean at high power can hurt the motor. I was thinking four stroke, but it's a two stroke?
Four stroke, I doubt you can access the idle mixture screw, they are usually covered. I'm assuming that is a pollution control thing.
I assume where you can buy two strokes, maybe they don't have to meet emissions standards and you may well can access the mixture screw.

We are still allowed to adjust our idle mixture. Next thing "they" will be banning diesels. I'm not joking.

[Mojadito]

On the newer Yamahas, conventional (chemicals, solvents) cleaning of the carburetor usually does not work. The passages in the carb are just way too small to get clean in this fashion. Use an ultrasonic cleaner. Soap, water and about an hour of ultrasonic vibrations fixes these carbs right up, you don't even need new gaskets as these usually survive the cleaning process. Take it apart as far as practical, then put all the parts in the unit with some simple green and water. Run it in the heating mode for about an hour, dry and reassemble.

[SeaSon]

Any time my 4hp Merc won't idle, I drain the float bowl by losing the screw at is bottom, pump the bulb a few times, tighten it back up, and away we go!

[GrahamHO]

According to an outboard mechanic I spoke to; because 4 stroke outboards use less fuel than 2 strokes, the 4 stroke carb jets are smaller and more easily blocked and harder to adjust. It seems to make sense.
I could never get my Honda 2 HP to start easily so I bought a Mercury 5 HP 2 stroke and it is no problem. I really like the idea of 4 strokes better though with their economy and lack of fumes.

[Waboson HR352]

All the jets need mechanical cleaning if you have not had success with carby cleaner. Some of the holes are so fine you will need the thinnest wire you can find. I have had the same issue and the problem was the tiny hole in the very end of the idle jet. The wire inside those ties you get for plastic bags is perfect, just strip off the outer casing.

[Scout 30]

Sometimes replacing is the only fix with 4 strokes. When I talked to the Honda dealer they said it's cheaper to replace carburetors than to try to clean them which rarely works. Try Boats.net for the best price.

[landonshaw]

Went to the dinghy and adjusted the idle screw, no change. There was a guy that rode up in his dinghy and offered his assistance. Actually a mechanic at a local marine! Told him everything I did, he asked if I had emptied the fuel line from the tank to engine, I had. We started the engine, it stopped when put in idle. Adjusted the fuel mixture and idle screws to no avail. He asked if I had cleaned the "low idle chamber". This is located under a metal plate on top of the carb, below the adjusting screw for the throttle. To him it sounded like the engine was not getting fuel when idling.

Took the engine home. Took the carb off, cleaned the jets, fuel mixture needle, float needle, opened the low idle chamber. It is just a couple of cavities. That must feed the plug when idling. Sprayed everything and reassembled. Took the engine back to the dinghy and started it up. All works now. It is running a little fast at idle, although I didn't have time to adjust. Nice to have back. Hope this helps others when the outboard has issues. s/v Aloisius. Dave


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[tbodine88]

I have a Tohatsu with the same problem although older. there are two screw settings on mine. I played with each until I got it to run at idle and all the way up to full speed. It was a hassle but doable.

[belizesailor]

Originally Posted by landonshaw

Went to the dinghy and adjusted the idle screw, no change. There was a guy that rode up in his dinghy and offered his assistance. Actually a mechanic at a local marine! Told him everything I did, he asked if I had emptied the fuel line from the tank to engine, I had. We started the engine, it stopped when put in idle. Adjusted the fuel mixture and idle screws to no avail. He asked if I had cleaned the "low idle chamber". This is located under a metal plate on top of the carb, below the adjusting screw for the throttle. To him it sounded like the engine was not getting fuel when idling.

Took the engine home. Took the carb off, cleaned the jets, fuel mixture needle, float needle, opened the low idle chamber. It is just a couple of cavities. That must feed the plug when idling. Sprayed everything and reassembled. Took the engine back to the dinghy and started it up. All works now. It is running a little fast at idle, although I didn't have time to adjust. Nice to have back. Hope this helps others when the outboard has issues. s/v Aloisius. Dave


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Good lesson learned...the majority of small engine problems can be resolved simply by tearing down and cleaning the carb. Spraying majic "stuff" in it is nor nearly as effective as good old manual cleaning.

[a64pilot]

Best thing as one poster brought up is if you have an ultrasonic cleaner, especially if it's a heated one, just regular cleaning Mr Clean in one is great, for carbon, old fuel varnish etc, Hoppes gun cleaning fluid is good, I use it to clean aircraft fuel injectors and they come out looking new.

I have one, but doubt I'll take it cruising with me.

For two stoke tuning you want one to idle as lean as it will smoothly run to keep it from "loading up" or fouling plugs, the idle mixture screw will adjust idle mixture, for high throttle settings, you want it as rich as you can get it, just before it "four strokes" as rich means cool and well lubricated, usually have to change jets to adjust high speed mixture.
My method for setting idle mixture is to adjust it to where it idles at the highest RPM, then adjust the idle screw for correct RPM.

[belizesailor]

And...adjusting the carb before isolating the problem is just masking the root cause. Best to clean well and then adjust if necessary.