Engine Shut Down

[JJRJR]

Back-story: 1992 Gulfstream with twin 1992 Johnson 150's. About 1,400 hours on the motors. I got this boat right after Thanksgiving and have been having work done to it all this time. When I got the boat, the main fuel tank had about 1/2 tank of fuel. The age or origin of this fuel is unknown. It is at LEAST 3 months old since I've had it, plus I have no idea when it was put into the boat. It's old.

The auxiliary tank was empty. Yesterday, a friend borrowed the boat to sea trial it. He added 20 gallons of fresh fuel to the main tank (with the old stuff) and 20 to the auxiliary. Yesterday, they ran the boat for 3 to 4 hours with no issues on the main tank. Today, they took it out again, and while on plane both motors shut off.

They switched the valve to use the auxiliary fuel tank and the engines started and are now running fine.

A couple questions. (All fuel filters, fuel/water separators are brand new.)

1) Clearly this is fuel related. Why would it run fine all day yesterday on the old fuel and die today? What's at play here?

2) Seems to me that if the old fuel clogged the filters, that even switching to the new fuel in the auxiliary tank would still be a problem if they are clogged?

3) What's involved in draining old fuel and cleaning a tank?

Thanks all!!

John

 

[DennisG01]

To me, it sounds more like your fuel pickup is clogged or possibly an internally failing fuel line from the pickup to the transfer valve. Ethanol can do wonders to older fuel lines.

 

[JJRJR]

That does make sense actually. It would explain why it ran fine on the fuel itself for 4 hours yesterday.

Thanks,

John

 

[suzukidave]

it could also be a stuck antisyphon valve on the main tank intake.

 

[CatTwentyTwo]

You might want to check to make sure your alarm system is working also. On my 94 Johnson a fuel restriction will sound the warning horn.

 

[jbrinch88]

Main tank pickup tube either blocked, broken off, or has a hole through it and you used enough fuel to get it below that hole. Antisiphon valve seized up, or bad fuel.

You can: pull the fuel sending on the main tank ( mark a line with a sharpie so it's easier to line up when reinstalling, even though they can only fit one way). Pump some fuel from the bottom corner of the main tank into a clear container ( corner depends on which way the boat sits/lists). Check for water or old stinky fuel. If present pump out periodically checking the fuel until all you get out is clean new fuel (if water is present it will all be on the bottom so make sure you keep your tube your pumping with on the bottom).

While the fuel sender is off, if it's near the pickup tube shine a light in the tank and see if you can notice anything obvious like it's broken off etc. If you cant find anything obvious, I would pull the pickup and any fittings with it as well since the anti siphon valve will be in one of them. Inspect the tube for holes and make sure it's clear.

If all this checks out its time to start making your way back to the motors.

 

[jbrinch88]

Also if you pull the sending unit, and the gasket is at all questionable replace it. If it's decent still, clean the tank surface carefully with a scotch brite pad and reinstall the gasket with some sealer like perfect seal etc.

 

[CatTwentyTwo]

Back-story: 1992 Gulfstream with twin 1992 Johnson 150's.

When I got the boat, the main fuel tank had about 1/2 tank of fuel.

John

Just another thought, when you say the tank was 1/2 full, was that going by the gage or did you dip the tank? If you were going by the gage and it isn't accurate you might not have had as much gas as you thought. Maybe the main tank is empty? It wouldn't take long for those twin 150's to burn thru 20 gallons of gas.

 

[seasick]

Back-story: 1992 Gulfstream with twin 1992 Johnson 150's.

When I got the boat, the main fuel tank had about 1/2 tank of fuel.

John

Just another thought, when you say the tank was 1/2 full, was that going by the gage or did you dip the tank? If you were going by the gage and it isn't accurate you might not have had as much gas as you thought. Maybe the main tank is empty? It wouldn't take long for those twin 150's to burn thru 20 gallons of gas.

This was my first thought also. I suppose when his buddty added 20G to the main, he may have noted the gauge reading before and after gassing up.

 

[bayrat]

That does make sense actually. It would explain why it ran fine on the fuel itself for 4 hours yesterday.

Thanks,

John

Do you only have one fuel pickup for both engines? Thats usually not the case, but it may be possible. If you have 2 pickups then I would say that you ran out of gas as the coincidence of both pickups having holes or clogged and both engines stopping at the same time seems highly unlikely.

 

[Fishtales]

My guess would be something in the fuel and/or bad fuel. Prob best to drain and get a good look inside the tank to start.
If problems persist, continue down the list folks have provided here.

 

[JJRJR]

Thanks guys. I'm having a tech sea trial today to see what's up. Also the throttle cables needed alignment. I'll post the results.

He (my tech) thinks the main tank is empty.

John