Vapor Lock

[foneman74]

Anything I can do to stop the vapor lock problem i am having with my 2001 mercruiser v-6?

 

[novicetech]

Re: Vapor Lock

You can try to let the motor idle for awhile after hard run with the blower running and maybe run the blower for awhile after shut down. Basically anything you can do to cool the engine compartment. What is the running temperature of the motor?

 

[SeaSkwurrel]

Re: Vapor Lock

Also you could try re-routing fuel lines further away from hot areas if possible. I've also read steel lines are more susceptible. If you have those, maybe swap them out for rubber.

 

[foneman74]

Re: Vapor Lock

Engine temp usually runs about the 140-160 range and already have rubber hoses. Until today i had this problem only after filling it up. But today the tank was half full and it did it. Usually when this happens i just open up the engine compartment and tell the kids to swim. After an hour or two it starts right up and i don't have a problem the rest of the day. Was just curious if there was a faster fix.

 

[Wotknot]

Re: Vapor Lock

Try wrapping the lines with alumanized insulation or with a wet towel after running it.

 

[Don S]

Re: Vapor Lock

Merc 4.3's are either MPI, TBI, or Carbed, suppose you could help us with what EXACTLY you have. An engine serial number would do wonders.

 

[foneman74]

Re: Vapor Lock

2001 Rinker<br />4.3 v-6 mercruiser efi with digital ignition<br />220hp

 

[Scaaty]

Re: Vapor Lock

Originally posted by foneman74:<br /> already have rubber hoses.

I have too go to the side with this. Rubber gas hoses are not Coast Guard approved for inboard engines...hard lines only.....I do not know the exact rule, but its a no-no. CG boards and sees that, $1000+ fine out here

 

[SeaSkwurrel]

Re: Vapor Lock

Hmm...I hope I don't get boarded then!

 

[Don S]

Re: Vapor Lock

I have too go to the side with this. Rubber gas hoses are not Coast Guard approved for inboard engines...hard lines only.....I do not know the exact rule, but its a no-no.

Might want to check your info there Robby. There are hoses that are allowed on the pressure side of the fuel system. They are CG certified, and every EFI engine has them.<br />On the suction side of a fuel pump, hose is allowed and quite common, but they are also specific kinds of fuel hose.

 

[DaveM]

Re: Vapor Lock

Hmmm, vapor lock on an EFI engine. Something here is not adding up right. Next time out you might want to verify this by setting a bag of ice on the fuel line. But I might be more inclined to think your problem lies elsewhere. Perhaps the fuel pump?

 

[hoot]

Re: Vapor Lock

maybe foneman's topic should be: motor hard to start when hot, of which vapor lock might be an issue. fwiw, i wrapped my fuel line with aluminum foil to reject some of the heat.

 

[thunderroad]

Re: Vapor Lock

I haven't had the vapor lock problem on my boat yet but we used to put a piece of that plastic-like split convoluted conduit over the fuel lines of our gas trucks in areas where they were close to heat. Use a piece that fits pretty loosely to give it a little air barrier. <br />It seemed to help them a lot. It would handle most any hot metal surface in an engine compartment except an exhaust manifold. That shouldn't even be a problem on a boat as they don't get nearly as hot to touch as they would in those trucks.

 

[Scaaty]

Re: Vapor Lock

Originally posted by Don S:<br /> Might want to check your info there Robby. There are hoses that are allowed on the pressure side of the fuel system. They are CG certified, and every EFI engine has them.On the suction side of a fuel pump, hose is allowed and quite common, but they are also specific kinds of fuel hose.

I will do that Don, and thanks. I could have pulled over the CG yesterday for a check up on my boat, and info. The local longtime friend and mechanic/owner of a long standing marina, said I need hard lines on my boat (long time ago), but its a 350 carbed, rubber to mechanical pump, then copper lines. Sometimes I forget that the new stuff is WAY different. Thanks for the heads up........

 

[foneman74]

Re: Vapor Lock

A friend of mine sent me this, any truth to this: "Most folks say to never use any gas that has ethanol in it...<br />Like the 10% stuff at some stations.<br />It burns much hotter than 100% gasoline causing vapor lock, and it eats the rubber in the fuel line to and inside the engine.It is hard on plastic also."

 

[rodbolt]

Re: Vapor Lock

vapor lock is actually quite rare with modsern fuels. its actually cased by fuel boiling in the lines. always remember that fuel under a vacum(suction side) boils at a much lower temp for every inch of vacum. on the pressure side fuel tends to boil at a much higher temp under pressure. its so incredibly rare to see a vapor lock on EFI that I have never seen it. however the list of stuff I aint seen grows daily. (kinda like my second list) I would look for another problem before getting up on the vapor lock horse a quick test is to run about like normal with the fuel pressure gauge on the rail. if after a hot soak you have fuel pressure at the start up attempt its not vapor locked.

 

[MrBill]

Re: Vapor Lock

Myself and some fellow boaters experience vapor lock in hot, humid weather and have experimented with a few simple low-cost/no-cost solutions. Here' some that work for us...<br /><br />1 - empty bilge as much as possible to minimize humidity in the engine compartment<br />2 - run blower continuously, especially during hot or humid days<br />3 - put low-cost air scoops on dog-house, gunwhale or other area to vent engine compartment while under power<br />4 - insulate fuel line(use foam pipe inslation, rubber fuel line fitted over metal line if used, wrap with other insulating material)<br />5 - add another blower, double engine compartment air evacuation<br /><br />Number 1 & 2 solves my vapor lock problems, a friend removed the two cup-holders on the doghouse and mounted forward facing chrome air scoops to vent the engine compartment (works well but where does the beer go...it used to get warm there anyway)