305 mercruser vapor locking

[huntingdeer]

1989 mercruser 305


It runs good cold but when i let it run for 10 mins it kills out and no fuel anywhere.Pump is good and it was switched out.When i first got it, it had clothes pins on the line.I took then off and figured someone rigged it.But found out people back in the day used then when the motor vapor locked.The clothes pins were took off when i got it.Any help to solve this?

 

[alldodge]

Re: 305 mercruser vapor locking

1989 mercruser 305


It runs good cold but when i let it run for 10 mins it kills out and no fuel anywhere.Pump is good and it was switched out.When i first got it, it had clothes pins on the line.I took then off and figured someone rigged it.But found out people back in the day used then when the motor vapor locked.The clothes pins were took off when i got it.Any help to solve this?

It may or may not be vapor locking but the current issue your discussing is not a vapor lock. Your running out of fuel, vapor lock happens after the engine heat soaks and then it won't restart.

Sure could use your engine serial number, but until then. Was the fuel pump switched with another or a new one? Did you replace the fuel filter, if not do so. Put a pressure gauge on the fuel line going to the carb. Fuel pressure should be between 4 to 7 PSI.

Check to see if you creating a vacuum on your fuel tank, when it dies open the gas cap and listen for air being sucked in. Better yet get a gas can and run your fuel line from the can to the fuel filter. If it continues to run after 10 minutes it's in your tank.

When the engine is cold your choke is allowing more fuel to enter the engine. Once it warms up the choke opens and the engine runs more lean.

 

[harleyman1975]

Re: 305 mercruser vapor locking

I'm with Alldodge on this one the problem is most likely either in the thank pick-up or between the tank and the fuel pump.

 

[huntingdeer]

Re: 305 mercruser vapor locking

I'm with Alldodge on this one the problem is most likely either in the thank pick-up or between the tank and the fuel pump.

i put a new pump on it.the carbs are getting no gas after about 10 mins.Ive replaced all the lines and vent is not stopped up on the tank.when the motor cools off it runs good again.Ive replaced the anti valve on the tank too.

 

[hall832]

Re: 305 mercruser vapor locking

More information on your motor is needed.

 

[NHGuy]

Re: 305 mercruser vapor locking

Try running it with the gas cap loose. If that fixes it, check for a blocked tank vent.

 

[NHGuy]

Re: 305 mercruser vapor locking

If the fuel line between the tank and the pump goes against anything hot, move it away.
And if it still quits after ten minutes you could have something getting into the fuel pickup.
A remote tank is a good test too.
Sorry about the poor writing, I am not too good on this device.

 

[huntingdeer]

Re: 305 mercruser vapor locking

Like others I seriously doubt it's vapor locked. You have an issue in the fuel delivery system. It really sounds like it runs until something clogs the pick up, you let it sit, the trash settles out of the pick up and you get to repeat the entire process again. I'd suggest opening the fuel tank and with a good flash light take a look inside the tank.

motor info b581047

 

[alldodge]

Re: 305 mercruser vapor locking

Try a remote tank, just pull the line off your tank and put it in a 5 gallon can.

When you run out of fuel I would guess your fuel filter is empty, ??

 

[huntingdeer]

Re: 305 mercruser vapor locking

Try a remote tank, just pull the line off your tank and put it in a 5 gallon can.

When you run out of fuel I would guess your fuel filter is empty, ??

That and the separator is half full(which means no fuel when it is half full)

 

[alldodge]

Re: 305 mercruser vapor locking

That and the separator is half full(which means no fuel when it is half full)

OK, your either sucking air or you have a restriction, I'm thinking your sucking air through a bad connection of a line or filter seal

 

[huntingdeer]

Re: 305 mercruser vapor locking

I have replaced alot in the last month. Im planning on taking it out this week and i will see.