Need Input - Flooded?

[brownski]

Does anybody know if altitude can have an effect on this. I started having problems last summer moving from Sacramento under 1000' elev. to Nv at about 5,000 elev. change fuel pumps then it did it again. Never had the problem before.

[meech]

thanks everyone ... appreciate it.

This is the answer from an older post by Engine Nut

A little clarification. The issue we have been seeing that is presumed to vapor lock is a condition that appears to be most prevalent on the 2007 model 340 engines with ETX CAT manifolds. The theory is that the extra heat generated by the catalysts allows the heat to build up in the bilge after the engine has been run for a period of time and then shut off. After it sits for a while a condition called "heat soak" raises the temperature in the bilge and allows the fuel in the line between the pump and tank to vaporize. The high pressure fuel pump will not pump vapor.

That being said, you can reduce the possibility of happening on any boat by doing a few simple things.

First, make sure your fuel filter is clean. As the fuel pump draws fuel from the tank through the filter, it creates a low pressure (vacuum) in the line. The harder the pump has to work the more vacuum is applied to the fuel. Fuel vaporzes at a lower temperature when it is exposed to a vacuum.

Make sure there are no restrictions in the fuel line between the tank and pump. The best condition is to have as straight and short of a line as possible. Each bend in the line can cause the pump to have to work harder and increase the vacuum.

After a hard run, try to let the engine run for a minute or two before shutting it off. This will help "normalize" the engine temperature and remove as much heat as possible from the engine. It might even help to disengage the shift control and raise the engine RPM in neutral to pump more water through the engine before shutting down.

Leave the bilge blower on after the engine is shut down to bring as much fresh air into the bilge as possible. Also, make sure the bilge vent hose isn't blocked, restricted or even disconnected from the vent and that the vent isn't blocked externally. It is not a bad idea on a hot day to lt the blower run all the time the engine is running .You'll also want to make sure to turn the blower on well before starting (if you shut it off) to make sure things are cooled off. This is not an unrealistic thing to do ... how many cars do you walk by on a hot day and hear the fan running after tha car has been shut off.

Your boat is significantly different than a car. The bilge of a boat typically does not have a lot of air circulating around it unless the blower is on. Also, cars have their fuel pumpslocated in the fuel tank.This keeps the pump cooler and allows the fuel between thepump and tank to be pressurized whichraises the vaporization temperature.

Try buying fuel from another source. We recommend using gasoline from a "Top Tier" supplier. Yuo can find which suppliers sell Top Tier fuel by checking out the following site. http://www.toptiergas.com/

I hope this gives you a little insight into vapor lock. It is a condition that has been around for a long time.It can be very frustrating but can be prevented in many cases by following a few simple procedures.
__________________
Larry Engelbert
Indmar Marine Engines
"Send Ed Down Under"

[yearround]

Does anybody know if altitude can have an effect on this. I started having problems last summer moving from Sacramento under 1000' elev. to Nv at about 5,000 elev. change fuel pumps then it did it again. Never had the problem before.

fortunately, we have not had this vapor lock problem. we have ran our boat at elevations as low as 3600 in lake powell to over 7000 in colorado. we have an 08 lsv.