Motor ran great for 2+ hours straight then when switched to idle died

[captain_strikes]

I have a johnson 120 vro 1990. Just cleaned and rebuilt all of the carbs (wouldn't start in water), after the carbs were done, she started up great and ran excellent! I took her down to the lake and ran around for about 2+ hours and burnt up half a tank. I was switching to idle, switching back to full throttle, mid throttle etc. Anyways, I went back shore to pick up my wife and switched over to idle... then the engine sputtered and died and wouldn't restart.

I've read it could be a dirty fuel filter? What do you think? (Half of the gas in the tank was about a year old but the previous owner said he added stabilizer to it so I topped it off with fresh gas and threw a couple cans of seafoam in)

 

[flyingscott]

What about the waterpump

 

[jakedaawg]

Would it turn over but not start ? Or just nothing? Did you check for spark? Could be a lot of things. When you say sputtered and died did it seem like fuel issue? I would doubt it's a filter issue.

 

[emdsapmgr]

Possibilities: 1. engine overheated, piston expanded due to heat and stuck in the bore of the cylinder. 2. You ran the fuel tank down over 2 hours and finally got to the bottom of the tank and it sucked up some water at the bottom of the tank and quit running. 3. An ignition component failed exactly at that point and now the engine has no spark. 4. VRO tank has water in it-sitting at the bottom of the oil tank. Finally ran the oil tank down and water is left. There are any number of possibilities. You need to do some testing to start eliminating possible failure modes. It is more helpful to us if you let us know just what troubleshooting you have done since the failure. Hard for us to make a guess without some information. It's normal to start testing for fuel and spark at each cylinder..

 

[captain_strikes]

Thanks!

I replaced the spark plugs and ignition battery yesterday, then lowered the motor down into a barrel of water. Primed it up (ball was hard) then turned the key. Started up immediately without issue. I have not added any additional gas. The oil tank is near full capacity. Gas tank is half capacity.

While i was on the water when i tried to restart it, it didn't act like it was even trying to turn over when i would turn the key.

 

[flyingscott]

Compression and spark test need to be done and what do you mean turn over the starter is turning the motor and won't fire or the starter was not turning.

 

[captain_strikes]

Starter was turning the motor but it wouldn't fire

It is firing right up now without issue now that i changed spark plugs and batteries. Idle sounds great as well.

Note: I didn't try to fire it up again that day after trolling back to the ramp, yesterday was my first time trying to get it to start after bringing it back home.

 

[jakedaawg]

Make sure you are cooling. Make sure you have oil in gas.

 

[emdsapmgr]

An overheat lockup would freeze the engine when overheated. The piston will expand an stick in the bore. Trying to restart with this condition, and the starter probably won't budge the flywheel. Let the engine cool overnight, and it will probably start right back up. At this point, I'd want to be sure the overheat sensor is activating the oveheat horn. If the horn does not work, it could be overheating and you'd never know it....You can get an overheat lockup once, maybe twice before you wind up with a catastrophic failure that will damage the powerhead.

 

[captain_strikes]

The flywheel was still spinning, it definitely wasn't locked when I tried to start it again. I did notice that while I was running around in those 2 hours that the motor had a steady stream coming from the pisser.

 

[oldboat1]

Sounds like you've been running out old gas that a PO says or implies is OK. I would get rid of what's in the tank before adding more. If it's a permanent tank, siphon everything out and maybe burn it in your car. Check it for water first, and run it through some kind of filter.

When you dump seafoam into a tank, you loosen up stuff in the tank and lines. The stuff doesn't necessarily go through the carbs (can muck them up), or the seafoam can loosen up stuff in the carbs and move it around -- just enough to clog tiny passages. Filters also clog up. The best solution is to pull apart the carbs and clean them, and change out any filters. But you may get lucky running through a tank or so of clean fuel.

Touch the tops of the heads when the motor is warmed up -- should not be too hot to touch, or it's overheating. Really need to change out the impeller with a new-to-you motor, if you haven't already done that.

 

[captain_strikes]

I'll try draining the tank and refilling with a tank of fresh gas. That seems like it makes sense. There very well could be some water in the tank, I have no idea. I did turn around fairly quickly and then throw it into idle before it died on me. Might have shaken the water up and sucked up into the engine.

 

[oldboat1]

Siphon or pump from the bottom of the tank (where the intake is also located). Let the fuel settle out in a glass jar, and see what you have. Gas will float on top of any water. If you run with a permanent tank, a water separator filter is a good idea.

 

[captain_strikes]

Just an update on this for future reference.

I drained the tank completely and installed a new fuel filter. Took the boat out on Saturday with a fresh tank of gas... ran like new. Did not have any issues at all!

 

[oldboat1]

glad to hear you got it solved.