2012 F20 Starts, But Putters Out Quickly

[Kola16]

Hello all! I have a 2012 Yamaha F20 remote start that started running funny. When I start it up it runs fine for 20 seconds or so, and then it sputters out and dies as if it runs out of gas. The gas is fresh, non-ethanol gas and the fuel filter is clean. It seems to run fine when I rev it, but besides that it dies.

- I've taken the gas cap off to see if it wasn't venting and no change

- I've ran the fuel line from the gas tank directly to the carb while pumping the ball in the fuel line and trying to run the engine and no change.

- I've "cleaned" the carb, but it was already spotless.

- I changed the spark plugs and insured they were both sparking.

- I blew through the air hose to the carb and it was clear

I did drive up onto a sandbar recently. Is it possible that sand went in the water pickup and is causing it to die at low RPMs or something? I'm at a dead end. I'm going to do a fuel pressure and compression test Saturday night...

Thanks for any advice!

 

[99yam40]

My guess is the pilot jet/passages are plugged up some.
prime start adds extra fuel at start up but then is shut off and it dies

Also I would check to see what timing is doing, that may be moved around at start up and then drop back

Just make sure with a timing light what it is doing and is in spec

but I am not familiar with that 4 stroke motor

 

[boscoe99]

Have you tried pumping the primer ball continuously when starting the motor to see if it will continue to run or not?

 

[mike_i]

I had the same problem with my lawnmower. It would only run while I'm pushing the primer bulb. The problem was the carb bowl gasket, causing the carb to suck air after running for a few seconds then dieing. Have you checked all of the gaskets? The problem doesn't sound like an issue with sand in the water pickup, it's a fuel issue. Have you tried another gas can and gas line?

 

[Kola16]

Have you tried pumping the primer ball continuously when starting the motor to see if it will continue to run or not?

Yes I have. The primer ball has hard to pump, and I'd like to think it ran a little better, but I'm not sure that it did...

The problem was the carb bowl gasket, causing the carb to suck air after running for a few seconds then dieing. Have you checked all of the gaskets? The problem doesn't sound like an issue with sand in the water pickup, it's a fuel issue. Have you tried another gas can and gas line?

I did check the carb gaskets and they appeared fine, but a rebuild kit never hurts. Just strapped on cash right now. I didn't try a different fuel line because I do not have one, but i took all the connections off of mine and just put the hose in the tank and pumped the ball and it was pumping fuel well. I then hooked the free end up to the engine after the fuel filter and after the fuel pump and still the same issue.

I'm going to take the carb apart again to do a second inspection...

 

[mike_i]

Did you check the fuel pressure?

 

[raczekp1]

are the spark plugs new? if are new then
1. while motor is runing take of fuel hose from fuel pump and check if fuel is pomping out from fule pump
2. while motor is runing check voltage with DVA adapter on cables liding from stator to electric primer. shoud be 24V on idle, 37 on higher idle and around 70V while runing on high rpm. often bad runing is cused by bad stator.
4. check elctric primer if there is good oring on it and check needle movement while conected to the car batery.
5. soak the carb in carb cleaner and blow with air

 

[Kola16]

Well I took the carb apart a second time and shot compressed air through all of the jet and followed it with carb cleaner. I found that two jets might have had a tiny bit of what appeared to be gasket glue or something in them. Anyway, I cleaned it all up, put it back together and back in the boat, and it runs great now! No bogging, no hard starts or anything. Runs through all of the RPM range. Thank you all for the advice!

Did you check the fuel pressure?

Funny, I went home to grab the fuel pressure gauge and compression tester just to see what I was getting, and I forgot both at home I keep the boat at my mom's house since it is much closer to my duck hunting grounds.

 

[99yam40]

Well I took the carb apart a second time and shot compressed air through all of the jet and followed it with carb cleaner. I found that two jets might have had a tiny bit of what appeared to be gasket glue or something in them. Anyway, I cleaned it all up, put it back together and back in the boat, and it runs great now! No bogging, no hard starts or anything. Runs through all of the RPM range. Thank you all for the advice!

good to here, and thanks for popping back in to let everyone know what fixed you problem

 

[mike_i]

Congratulations on hopefully finding the problem. Thanks for the update.

 

[Kola16]

Took the boat duck hunting yesterday in as rough of seas as a 14' with a 20 horse can take. Nice cold Washington saltwater spray in the face at every wind wave. Engine performed flawless for the 5 miles out, and 5 miles back. Didn't die once and have dinner to show for it!