VAPORLOCK

[davet]

I have a 2001 tige 20i with a 350 mecrusier motor. The motor starts fine when unloading but the problems begin after the boat has been running for awhile. if it sits still for more than 10 minutes it wants to act
like it has run out of gas. it will start but slowly dies due to the lack of fuel. The only way i found to get it running again is to remove the fuel line from the fuel filter and let it drain for a couple of seconds,then reconnect it. After doing this it runs fine but i dare not cut the motor off
cause if you do it happens again....I have replaced the fuel pump,(3 times), cleaned out the gas tank. Replaced the fuel line and fuel filter.
I also removed the check valve in the gas tank but no luck......
Is anyone else having these problems???? any cures???
Note: This motor is fuel injected....

[Matt Garcia]

Have you replaced the water/ fuel seperator? Dont know if that will help or not, Tige MD would probably know the answer to this.

[Ruune]

since its cold this time of year, you might want to try getting some cold water in a cup and pour it over the fuel line to cool it. This will reduce the temp of the fuel and prevent it from evaporating so quickly. Just dont get it in the throttle body! Also, try putting some sort of insulation around the fuel line from where it meets the carb, to about 1 foot before. Also, try replacing the air/fuel separator (like Matt said), and the fuel filter.

[davet]

Yes i replaced the fuel-water seperator filter, i also went as far as to replace the mount for the filter. I thought it might be cracked... I also put foam insulation around all the fuel lines and fuel rails on top of the intake. no luck.....The only thing that i have'nt replaced is the 2 lines that run from the fuel-water seperator to the fuel pump.... That will be my next project in the spring....The fuel pump is one that has a bult in cooler that uses the fresh water to cool the fuel before it goes into the motor....What about the vent check valve that runs from the tank to the outside of the boat? This is the only thing that i have'nt taken apart yet.

[Tige M.D.]

i am not 100% sure it is an actual vapor lock you are experiencing.
in 99'-01' mercruiser used a ignition module that would simulate a vapor lock when it was about to fail. the engine would start right up in the morning, but , once it got hot it would break down the ignition.
next time this happens, check 2 things,
1. check for spark at any of the plugs

2. when looking at the front of motor, you will see 2 black fuel rails on either side of the throttlebody. on one of the rails there will be a brass cap, under that cap is a shrader valve(like on a bicycle tube). get a rag and depress the valve. this will vent any air out of the fuel rail if it is a vapor lock. if it is solid fuel then it is not a vapor lock.

i have seen alot of these ignition sensors fail (well over a hundred). geing that it is winter i find it hard to believe the fuel is getting that hot. also it seems that you have changed out everything in the fuel system. you absolutley have to put the check valve back in the fuel pick up. it is an anti-syphon valve. it is federal law that all inboard engines have this in place.

your fuel system should have no more than 5 inches of vacuum in the suction line from the tank. otherwise it will put too much load on the pump causing it to heat up and fail.

check the ignition system, you might be suprised.

[davet]

Thanks for the info... need to clarify one thing....these problems happened during the summer ski season....The boat is in storage now...
too cold to ski at this time...Yes it did have air in the fuel rails and i bled it but it would just keep pumping more air and a little fuel...After i removed and bled the line from the tank it would be just fine....After i replaced the fuel line from the tank to the fuel- water seperator i rerouted it just in case it was getting pinched somewhere....The problem still happened...
Note: During the summers of 2001 and 2002 the where no problems of anykind with the motor...2003 and 2004 is when it started to happen...I did nothing different when i winterized or brought it out of storage during those years so thats what has got me drawing a blank as to what the problem is...

[lee]

Have you added the extra Mercruiser fuel pump? Around the end of 2001/2002 Mercruiser made us add a second fuel pump to the engines to help with that problem.

[davet]

No i didn't know about adding the second fuel pump. Did mercruiser offer this as a factory deal to fix it or ? If they did how do i contact them?

[Tige M.D.]

the boost pump? i forgot about that.
p/n 861155a12 $450

we installed some under a service advisory but i don't know how long they will honor that. call your local dealer.
mercury consumer affairs/tech services 405/743-6566

[lee]

They sent a service bulletin to the dealers about the situation and what parts to install.

[davet]

Thanks for the info...i will give them a call....I don't want to go through the dealer that i bought the boat from.....they do not do quality work...

[Tige M.D.]

go to mercury marines web site. they have a dealer finder that lists their platinum dealers first. that means the best per their csi scores
and certifications.

[davet]

I sent an email to the mercruiser customer service center about my problem....They first said sorry that it was a common problem with boats.....Then they sent me another email saying that they were going to talk to their experts about the problem...They came through for me!!!! All I have to do is take the boat back to my dealer and have them check it over once more so that they are sure that vaporlock is the problem...Once they are sure that it is vaporlock they are going to install the boost pump kit at no cost!!!!! How about that !!!! Thanks for all the info on this problem from all the tige owners... You have been a great help.....

[Tip]

Davet,
Where did you buy your boat? I have a feeling you and I bought our boats from the same dealer.

-Tip

[davet]

I bought it from tige boats of the triad. they are now known as big boyz toyz i think. i have no problems with the person that sold me the boat its just that it seems like they can't keep the same mechanic around...