20 hp yamaha 4 stroke issue

[Chaneylake]

motor runs about 5 seconds and then dies.

I drained fuel line, carb, and put fresh ethanol free gas in tank

ethanol free gas is all that i have ever used.

any suggestions on what to look for?

 

[Urban_Hunter]

Sounds like the Fuel pump isn't keeping fuel in the carb bowl. Usually because the pump is sucking air at a leak somewhere, typically where the detachable fuel line connects to the tank or the engine. If you keep the primer bulb tight by hand will it run?

 

[Chaneylake]

Sounds like the Fuel pump isn't keeping fuel in the carb bowl. Usually because the pump is sucking air at a leak somewhere, typically where the detachable fuel line connects to the tank or the engine. If you keep the primer bulb tight by hand will it run?

give me a few minutes and I will go outside and give it a try.

 

[Chaneylake]

that didn't change anything
still goes dead
i tried the bulb squeeze tip 5 times.

 

[tacoma2002]

I'd do a spark test on it just to rule that out. If it passes ignition testing then it's most likely going to need the carburetor removed and cleaned.

Ethanol free fuel is a great practice, but unfortunately it's not the end all be all to carburetor issues. Even a piece of small trash that makes its way in there can cause issues.

I'd replace the fuel line (the gray fuel line is known to break down on the inside and stop up everything) and clean the carb well.

 

[bigjohn]

I had one doing that same thing one time and it ended up being a pin hole leak in the carb float

 

[7mm08]

You got a water separator on that boat? Looks like an oil filter

 

[Chaneylake]

I am no mechanic.
I have a great mechanic coming over Sunday afternoon. I will definitely show him all the details that each of you have posted.

Thank y'all.

 

[FLTENNHUNTER1]

How old?

 

[Chaneylake]

How old?

Motor is about 7 years old
Mechanic is almost 70

 

[Hawk]

Check your pick line in your fuel tank.

 

[FLTENNHUNTER1]

Gummed up carb/bowl/jet would be my guess.

 

[Chaneylake]

Check your pick line in your fuel tank.

I am confused in your statement

 

[Hduke86]

I am confused in your statement

I'm assuming he meant the fuel pick tube in the gas tank to make sure it's not getting choked out by junk from the bottom of the fuel tank

 

[Hawk]

I am confused in your statement

I'm assuming he meant the fuel pick tube in the gas tank to make sure it's not getting choked out by junk from the bottom of the fuel tank

The above and also cracked /broken spots in line causing loss

of pressure.

 

[Chaneylake]

The above and also cracked /broken spots in line causing loss

of pressure.

Tank is clean and no visible leaks in the line.

 

[Tenntrapper]

Tank is clean and no visible leaks in the line.

Is there a drain screw in the carb bowl? If so, as soon after it dies as possible, take out that screw and see if bowl is full. If not, the float is stuck.

 

[Chaneylake]

We just finished cleaning the carburetor.
Motor seems to be running just fine now.
I will run her upstream in the Hatchie River tomorrow before I head downstream.

 

[FLTENNHUNTER1]

We just finished cleaning the carburetor.
Motor seems to be running just fine now.
I will run her upstream in the Hatchie River tomorrow before I head downstream.

Good deal. It is a good habit to drain the bowl if you don't use the motor regularly. Should be a screw on it to drain it. Be sure to valve off the gas line or disconnect it. Fuel conditioner helps to prevent this. I use Star Tron.

Amazon product ASIN B00D3IEIY0

 

[dranrab]

The ports and passages in those smaller 4 stroke carbs are tiny. They can be pretty darned fussy. I had the same motor. It required 2 trips to the mechanic to sort it out. A also had a 4 stroke 50HP Merc with 4 carbs. Same story. As little fuel as they burn, run non-ethanol AND fuel conditioner.

 

[megalomaniac]

If it still acts up, just replace the entire carb. The idle jet on them is TINY and almost impossible to clean.

$225 for a new carb for that motor IIRC.