Possible fuel pump problem?

[MEDIC151]

I don't know if this is the definition of vapor lock or not, but here is my problem. Out on the lake the other day for the first time and boat started and ran fine for the first hour or so. I tried to start it and it fired, ran really rough, then died and wouldn't start again. I got a tow back in.

I changed the fuel filter and took it back to the lake on sunday. Started fine so I thought it was fixed. Same scenario as above but this time I checked the valve stem looking thing at the fuel rail and vapor came out with very little liquid gas. The fuel pump was very hot and the motor temp showed just under 180. I left the cover open and let it cool to about 145 and depressed the valve stem at the fuel rail till all the vapor was gone and raw fuel came out. It started just fine and ran great. Put it on the trailer and took it home.

My question is this I guess.
Why would it start this after 3 years of running fine and starting fine with no change in the motor temp? Is this just a fuel pump issue like needing to be changed? Also, can I get a lower temp thermostat to put in also to help with the temp around the motor since the pump is so close to the block.

Any help is appreciated.

Thanks

Medic

[mmandley]

I don't know if this is the definition of vapor lock or not, but here is my problem. Out on the lake the other day for the first time and boat started and ran fine for the first hour or so. I tried to start it and it fired, ran really rough, then died and wouldn't start again. I got a tow back in.

I changed the fuel filter and took it back to the lake on sunday. Started fine so I thought it was fixed. Same scenario as above but this time I checked the valve stem looking thing at the fuel rail and vapor came out with very little liquid gas. The fuel pump was very hot and the motor temp showed just under 180. I left the cover open and let it cool to about 145 and depressed the valve stem at the fuel rail till all the vapor was gone and raw fuel came out. It started just fine and ran great. Put it on the trailer and took it home.

My question is this I guess.
Why would it start this after 3 years of running fine and starting fine with no change in the motor temp? Is this just a fuel pump issue like needing to be changed? Also, can I get a lower temp thermostat to put in also to help with the temp around the motor since the pump is so close to the block.

Any help is appreciated.

Thanks

Medic

Only thing i can think of that would have changed your fuel issues over the last 3 years is the addition of more ethanol.

As for changing the Thermostat to run the engine cooler, it would help but not like your thinking. All it would do it take the engine longer to each operating temp and such. The engine will still give off a very similar amount of residual heat.

I dont have any good ideas right now as to help prevent this issue. So fare it has been wide spread with boats 2 to 3 seasons old.

[xlvgg]

I have a 07 XLV. Last July I was at Lake Powell adn the first morning we put her in and went ahead of the house boat to look for a beach to park the house boat on. We ran for about 45 min cruising around. We went back to the marina and when the house boat was ready to leave the boat wouldn't start. I called my dealer and they told me to put a cold towel around the pump. I did and after a little while it started and ran fine. This happened again later in the day so I called a shop in Page, Bill and Tony's boat shop, awesome people. He worked on the boat late into the night and then early in the morning and had it all ready to go. He said that in the fuel line there is a safety ball that stops back flow into the fuel tank. He said it was wedged to tightly in the line so he loosened it a little. I thought he was going to charge me a ton. Not so 300 bucks. It has ran great ever since. Never have noticed the problem again.

[zabooda]

It's the gas. The way gas is blended seems to change each year. People are having problems with messing systems up after leaving the gas in for a few months even with Stabil. I did find this website to be interesting:

http://www.randakks.com/TechTip56.htm

[MEDIC151]

So if I drain the tank and put in fresh gas this will fix it? I guess provided the backflow is not messed up also. I am still running on the fuel from last seasons winterization which was a full tank and stabil. I just can't see why it is vaporizing the fuel in a contained area under pressure. I guess that will be a cheaper fix to start with.

[zabooda]

The people I'm seeing having fuel problems are draining the tank and using Seafoam. I'm not sure what that is but it appears to clean the parts.

[gcnettl]

If you have a fuel/water separator, this is suspect to vapor lock. I'm not sure of the specs on the fuel pressure, but you may buy or use a loaner fuel pressure gauge from auto zone to check your fuel pressure at that valve.

However, you should get fresh fuel when you depress that valve anytime after running. Maybe your pump is getting hot and not working?

As far as the thermostat, I would not recommend changing it or running without, as it brings your trans fluid up to operating temperature as well as maintaining engine temperature.

[MEDIC151]

I know the fuel pump is getting hot, but I can hear it charge the line everytime I turn the ignition on. It just seems to me that somewhere after the pump and before the fuel rails, it is vaporizing and not allowing the injectors to open. As soon as the vapor is released, it starts right up and runs fine.

Thanks for the suggestions, keep em coming. Hopefully I will get this resolved and let everyone know the fix just in case this happens to someone else.

[gcnettl]

Fuel Pressure Regulator Test
This test checks the operation of the fuel pressure regulator to make sure it changes line pressure in response to changes in engine vacuum. This is necessary to maintain the proper operating pressure behind the injectors and to compensate for changes in engine load.

With the engine running, disconnect the vacuum hose from the pressure regulator. As a rule, fuel system pressure should increase 8 to 12 psi with the line disconnected. No change would indicate a faulty pressure regulator, or a leaky or plugged vacuum line.

If the diaphragm inside the regulator is leaking, engine vacuum will suck raw fuel into the intake manifold through the vacuum hose (look for fuel inside the hose).

http://www.boatfix.com/merc/Bullet/99/99_07.pdf - For mercruiser engines, but same principle.



Supra recommends that after running, in other words once engine has ran and has become hot, normal operating temperature, to not suddenly kill it but rather let it idle for a little bit, blowers on. After killing engine, leave blowers on while sitting. This greatly lowers the engine compartment temperature, thereby cooling everything in it.

Indmar makes a two pump system to solve this, if it gets to that.

Winter fuel has a different volatility than summer fuel. In other words, gas supplied in the winter is more volatile than gas supplied in the summer. This is for better starting in the winter, among other reasons. There is a rating assigned to this, TPV. So, if you have winter gas, in other words, the gas you filled it with when winterizing in the fall, then this gas is more volatile than summertime gas. This winter gas will vaporize more quickly than summer gas. Additives in gasolines also change volatilities in fuel. Additives are constantly changing, so what might not have been a problem last year, could be a problem this year.

Location of the fuel filter can also affect the temperature of the gas before it reaches the fuel rail, or if the pump is not located in the tank, then the gas before it reaches the fuel pump. In other words, a fuel filter would be better placed near the tank, not in the engine compartment.

As your boat is out in the heat of the day, the fluids inside of it warm, as well as fuel in the tank. This affects vaporization.

I feel your problem is only vapor lock, and if you follow the instructions on cooling down your engine and using your blowers, and getting fresh gas, the problem will be solved.

If you wanted, I don't really see where it would hurt for maybe a 170 or 160 temp thermostat swap. These engines are designed to operate in that range, 165 to 180, along with the trans. This would lower temperature as well.

The fuel rail is very suspect to get hot, and combined with other conditions, the fuel there can be really hot.

[MEDIC151]

Thanks, I think that is the problem exactly. I am going to drain the tank and replace the fuel. If that doesn't work, I'll move on to the next solution. The fuel filter is right by the tank, so I don't think that it is affected as much by the heat as the rails are. I'll keep everyone updated with the results.

[brownski]

I have been fighting a similar problem. since llast year and mine is on a '99 carb engine. I just drained gas and am going fresh plus marine Sta-Bil +new filter + new water sepaprator+considering replacing the anti sipho valve on top of the tank at the fuel pick up. replaced the pump last yerar and symptoms returned after 2.5 hours. Last time mine died it actually died while heading across lake at about mid throttle. and wouldn't restart. Hope we can figur this crap out. Hate being on the lake, dead in the water.

[gcnettl]

Carburetors have their own set of problems, none of which is vapor lock.

First off, the draining of the tank might solve your problem. The Sta bil should remove any residual moisture that is in the tank. You could have simply gotten bad gas.

If problem is not solved, I would try a little diagnostic work. Keep a can of starting fluid with you in your boat, away from heat and light and amps and all that good stuff. Also keep a spark plug with you. IF your boat does this again, unplug the coil wire from the distributor and put your plug on the end, ground it to the engine and spin the engine over. Observe the spark at the plug and note the color. You want a bright blue spark, not red or yellow. If no spark is observed, I would suspect ignition control module. If weak spark is observed, suspect ignition coil.

If spark seems fine, then note if fuel pump is coming on when you turn ignition on.

If pumps seems to be functioning, I would suspect the carb, and look to having a rebuild kit put in it.

[brownski]

Thanks gc,

I'll keeep all that in mind when I get her on the water. gonna do a fake a lake run tomorrow with fresh gas and filters.

[MEDIC151]

An update on my problem. I took the boat out last night and it started fine as usual, ran around the lake to get the temp up and took a fuel pressure reading. It showed 4 and was running good. Stopped and floated for a little over an hour letting the heat soak build. Started the motor and just like before, it ran rough and died and would not restart. Pressure gauge started at 4 and dropped to 1 while it was sputtering then to 0. Fuel rails were very hot and so was the pump. The ECM was not very warm so I don't think that was it. Cooled the motor and released the fuel pressure and it started up and ran like a bat out of hell.

I am almost positive that it is the winter blend fuel that is still in it so I will be pumping that out and refilling it. Will let ya'll know if this is the cure.

[brownski]

Carburetors have their own set of problems, none of which is vapor lock.

First off, the draining of the tank might solve your problem. The Sta bil should remove any residual moisture that is in the tank. You could have simply gotten bad gas.

If problem is not solved, I would try a little diagnostic work. Keep a can of starting fluid with you in your boat, away from heat and light and amps and all that good stuff. Also keep a spark plug with you. IF your boat does this again, unplug the coil wire from the distributor and put your plug on the end, ground it to the engine and spin the engine over. Observe the spark at the plug and note the color. You want a bright blue spark, not red or yellow. If no spark is observed, I would suspect ignition control module. If weak spark is observed, suspect ignition coil.

If spark seems fine, then note if fuel pump is coming on when you turn ignition on.

If pumps seems to be functioning, I would suspect the carb, and look to having a rebuild kit put in it.

Changed that old fule, filter and wter separator. New gas with Sta-Bil and she ran as good as ever all week long.

[aintskeered]

MEDIC151, I had the same problem but when mine was very new... Fighting the "right blend of fuel" as it changes over the coars of the year and where purchased. was driving me crazy!

I finally fix my troubles with a simple move of the water lines. There were a couple of cross over lines from the exhaust manifold and transmission that layed aginst the fuel pump. A little re routing and a couple tye wraps to hold them away from the fuel pump. This allows more free air around the fuel pump, also not hot lines laying against the pump. I have not had it do this to me since. Another quick fix for it if dose happen while out playing, and you NEED it to start right away. Wet a towel and place on the fuel pump to cool it intel it starts.

As I understand the fuel system the pump has a bypass line right at the pump instead of at the far end of the rails. This will add heat to the fuel and aggrivate the problem. Get as much free air around the pump as you can to allow the air to cool the pump.

[MEDIC151]

I'll give that a try as well, thanks.

[MEDIC151]

Update:

I ran most of the fuel out, down to a 1/4 of a tank and have pumped out the rest. I am going to add seafoam and get some new gas. I moved the lines as much as possible to get the heat away and removed the carpeted wall behind the observer seat. I am going to let the boat do its thing and see if any of this fixes the problem. I'll let ya'll know.

[MEDIC151]

I think I got it fixed. I pumped the rest of the gas out and put in seafoam and 91 octane fuel. Rode around on the water to get hot and then stopped for an hour or so. Started right up and ran fine. It wasn't as hot outside so I hope that isn't messing up the results but I'll see about that this week. Thanks for all the suggestions.

[kaneboats]

Glad to hear all is OK again.

[aintskeered]

Glad to hear, hope it all stays well

[mallardsjason]

I have had same problem with my 2009 Outback.. I have been having to open my motor hatch and turn the blowers on and let it stay on for about 15 to 20 min before it will crank rite.. so I need to try and move the fuel lines away from the exhuast as much as i can.. I have been so sick of this every weekend.. bc everytime we get ready to go ski or whatever i have to sit there that much longer before we go..

[dtlaine]

For anybody with a carb engine: be sure to keep in mind that the oil pressure sensor could be the problem whenever you have intermittent running issues. It happened on my previous boat, and it's tough to diagnose because it would work sometimes and not others. It cuts the voltage to your fuel pump if your oil pressure goes away.

[MEDIC151]

Ok, 2 times out and no more problems. I can't believe that it was the fuel, but I'll take it since it was a cheap fix. Now onto the vinyl issues. Again, Thanks for all the help.

[spokanedj]

First, I'd like to say thanks to everyone who has posted on the fuel and vapor lock problems. It has helped me a lot and got my Moomba back running.

I have a 2002 Mobius V with TBI. New owner this year, however close friend was the previous single owner. First two trips out this year was fine, no issues. Third trip was infamous "run for a while, stop and swim for a while, won't crank, tow to shore". Put the boat in the water the next day and it ran fine again.

Next weekend Friday even hoter, repeat third trip experience.

This is when I researched on this board and found all the vapor lock issues and thought I knew how to deal with it. Float test ran fine next morning, took it on a long trip next day. It cranked and run fine until we got about 50 feet from the dock and it spurted and died. Paddle to shore and spent about 2 hours trying to figure out what the problem was. Never could get it to fire.

Finally got it back to the house and replaced Plugs, Cap, Rotor, Fuel Seperator and no change, still will not crank. Pulled the fuel feed line to the TBI and it was dry and not pumping anything. Kept going back and never could get fuel from the tank.

Removed the ant-siphon (ball valve) from the tank feed line and although it would open with a good amount of force, seemed too much for the low pressure fuel pump to deal with.

Ordered a new valve from local dealer, but also grabbed a 1/4 NPT-3/8 Hose adapter from local Ace store and popped it in. Within a couple key turns had fuel to the TBI input line. Took the boat out today, ran like a champ and not once had a cranking issue. I'm certainly going to put the anti-siphon valve in (when it comes in) and hope that the LP fuel pump isn't really the issue.

[fireman]

You are not alone. I have been dealing with this issue for 3 seasons now and still working on it. This site is very helpful. I will try it. Thanks!

[Buttafewcoe]

2004 5.7L carb. Outback. fuel pump not getting power. can hook it up to an external source and the pump runs. oil pressure guage works (at leats it's showing that it works) but motor not getting gas.
.
my question is where is that oil pressure sensor at?
.
B

[Buttafewcoe]

neber mind, think i found what i was looking for
.
thanks anywho
.
B

[Buttafewcoe]

Jrrrr, hope all is well. There is a 3 prong oil pressure/fuel pump switch just port and under the distributor. It is a safety device threaded into a oil pressure port. There is a Orange (batt), purple(ign), red(fuel pump hot), wire on the switch. When the engine is running (and the switch working properly), and there is oil press., it will activate the fuel pump and the motor will run. If no oil press. is detected, no voltage is sent to the pump and the motor won't run, hence the safety feature from locking a motor up. There are a few things to look for. First, verify your ground at the fuel pump, and the wires are firmly on. With a test light on the red post of the switch, while cranking, the light should come on and power should be at the pump. If the light comes on at the switch, verify with the same test on the gray wire on the pump. If no light present there, it is a wiring issue between the pump and switch. While cranking with the light on the red post, and it doesn't light, it is 1 of 2 things. There is debris in the small intake port of the switch, which may or may not be cleaned out by removing and shaking and inspecting (DO NOT USE A SOLVENT TO CLEAN). If this does not work, order the 2 prong Hobbes replacement switch through your dealer or Indmar. Hope this helps, keep us posted. Brian Raymond

[GoBucks]

I doubt it is the gas. I have the same problem last year and now this year. I ordered the second fuel pump system. Working on installing it now.