View Full Version : how did you fix your vapor lock problem?

06-01-2011, 03:32 PM
Any suggestions on what you did to fix your vapor lock problem would be appreciated. Considering: regular course of stabil and initial dose of heet water remover (even though I don't use ethanol gas I do get it from marina and could be poor quality); running blower constantly; possibly replacing fuel line between pump and filter with larger diameter, straighter run and insulating it.

Leaving hatch open on direct drive every time we stop to swim or eat lunch in boat is just not a workable thing - no room at all in the boat plus kids could fall into hot engine compartment.

Please reply if you've had vapor lock issues and you've been able to tame them.

KG's Supra24
06-01-2011, 04:21 PM
I use gas without ethanol and do not have any problems. It is bought on land at a high turnover location.

I have used gas with ethanol less than 3 times and had vapor lock one of those times.

I believe some add another fuel pump? but above is about all the help i can be.

06-01-2011, 04:25 PM
thx. I called indmar and they confirmed I already had 2 fuel pumps and can't add a 3rd on this configuration (320 hp throttle body injected Assault). Keep the boat on a lift at marina and am kind of stuck to buy the marina gas. They swear there is no ethanol in it and so I'm thinking there may be a bit of water in it. Thinking the cure is stabil / heet for that.

Plus, I'm definitely going to run blower and work with a mechanic to re-run the fuel line in a larger diameter and insulate it.

06-01-2011, 04:53 PM
vapor lock here a couple of times. I just make sure and run the blower during every run. goes like this:
-start the blower
-start the boat
-turn boat off
-turn blower off after a minute or so.

has cured almost every time, but the one time it did happen after that, I just took a cup of water, dumped it on the fuel pump located next to the motor and it fired right up..

I don't take the time/energy to locate non-ethanol fuel, as I think it's going to get harder as time goes on, and buying seafoam/stabil is somewhat expensive..

06-01-2011, 06:33 PM
So you are supposed to run the blower all the time? I thought it was for sucking out possible fuel vapors right before you start the engine?

06-01-2011, 07:27 PM
it pulls some of the heat out of the engine compartment. heat is the enemy when you think of vaporlock. fuel that has ethanol has a much lower boiling point than non-ethanol fuel.
you have a small block engine in an enclosed environment generating lots of heat and that heat has nowhere to go. the fuel lines/pump absorb that heat, you turn the boat off, the gas stops flowing and now it starts converting to vapor. when you start the boat up, the pump can't pull the gas.

running the blower has helped me. only happened once since then. no guarantees, but it's a cheap part and really can't be heard much over the engine.

06-01-2011, 07:51 PM
I have always just run the blower to make sure no gaseous fumes in the engine compartment at ignition, but they are telling me to run it continuously. My vapor lock doesn't happen when I just shut the engine off for a few minutes - it happens when the engine is off for an extended period of time - like anchoring to swim, going to a marina to eat lunch - when the boat is off for 45 minutes to a couple hours and sitting in the hot TN sun. Happened twice recently - both days where it was around 95 outside.

They are saying run that blower the whole time the boat is off. Gonna try it. Also going to be using some fuel additives regularly to make sure no water / ethanol in gas.

Any other suggestions? Thinking of paying to have a larger diameter fuel line run with a straighter line, and insulated too.

06-01-2011, 08:17 PM
Since you have a DD but don't want to fully open the clamshell when you anchor to swim, perhaps you can devise a way to partially prop it up to let the hot air escape. Definitely run the blower all the time that the engine is running if it's a hot day.

06-01-2011, 10:43 PM
volfo - couple of things that I have tried/used that have seemed effective and an idea I plan to look into this summer:

1) marine stabil
2) run blower (as already stated)
3) open engine compartment and plug in one of those 12v automotive fans to push fresh air in
4) cooler with cold water. pour cool water on fuel filter.
5) cooler with cold beer. drink beer if 1-4 fail.

planning to install in-line blower fans on the forward fresh air intakes on the blower switch so that I'm pushing fresh air in as well as engine compartment air out.

06-01-2011, 10:59 PM
I mounted a blower pushing air directly onto the fuel pump, seems to help. I leave it on all the time and also leave the factory blower on too. One pulling cold air in and one pushing hot air out.
I also put 4 clothes pins on the fuel lines (old trick from back in the day)around the fuel pump.

06-01-2011, 11:15 PM
Wrap the line and fuel pump in the foil bubble wrap. It doesn't let any heat through.

06-02-2011, 01:48 AM
Wrap the line and fuel pump in the foil bubble wrap. It doesn't let any heat through.

Very simple and good.......let the fuel cool the pump and keep the heat out...... but you have a carbed motor not mpfi which I believe is where most of the vapour lock occurs. But I could be wrong , but I do like your solution...

06-02-2011, 11:40 AM
thx for all the suggestions. keep them coming if anyone else has any ideas. Several I have heard before and planning on trying, several are new and might try. My mechanic already told me the wooden clothesline pin trick and I have 8 clothesline pins on the fuel line now. I'm also wondering if it is somehow vaporizing in the rubber fuel line between the tank and the first fuel pump and if anything can be done there. Definitely like the idea of insulating the fuel lines because that would be super easy I would think. Should be able to just wrap something around it. Will investigate right material.

06-02-2011, 11:45 AM
Can someone explain the clothespin thing?

06-02-2011, 12:30 PM
ditto. I would think pinching a fuel line with those could cause some premature leaks if you keep them in the same location.

06-02-2011, 12:42 PM
Sounds like they are on the pump, not the line. Are these to pull out heat?

06-02-2011, 04:30 PM
My mechanic said the wood on the lines will help draw the heat out of hte lines. I'm not sure, sounds a little funny to me, but that's what he said. I could see it also slightly insulating the line. He said it was an old trick used in cars in the summer in the south when they had carbs.

It won't pinch the line. It's just a clothesline pin clamped on over the metal pipe - it doesn't pitch hard enough to restrict the line or damage it.

06-03-2011, 10:24 AM
Sounds like hogwash to me. Wood is not the best conductor. Aluminum foil would work better but it would also conduct heat into the line.

06-04-2011, 02:16 AM
It's in the same category of water witching. Pure magic.

07-03-2011, 06:12 PM
To add to the above "solutions" to vapor lock. I live in Monroe where the folks from hell don't come to cool off. It was 113 heat index yesterday and I, of course, vapor locked coming out of the marina after grabbing a burger. I ran the blower the whole time, not an option to turn it off in this kind of heat. The fix? Run cool water over the fuel filter as stated above. The colder the better. Remove gas cap (very important). Turn key for a couple of seconds before cranking to re-prime, then crank engine with gas cap removed. You may even notice a "poof" or burp. While engine is running normally now, screw the gas cap on and head on out.

This is the procedure that I've nailed down that has worked for me, since in this heat running ethanol or not, I vapor lock just about everyday that the temp is at 100 or above.

Hope this helps some others and any feedback is appreciated!

07-03-2011, 08:52 PM
You need an ice bag for the pump.

07-03-2011, 10:58 PM
So is the actual problem the pump getting too hot or the metal line going from the pump to the motor getting hot? Reason I ask is to me mounting a fuel pump right beside the motor with a metal line connecting them is only asking for problems. The motor is hot and the pump is mounted right beside the motor and on top of that is connected to the pump with a metal line which can easily transfer heat. Didn't know if changing this line to a different line or moving the pump could maybe be a solution. I know mine has vapor locked a few times.

The part I hate is that the motor fires right up and about the time I pull out of the boat slip is when the motor dies and doesn't fire back up. I have had to swim back to the boat slip with a rope twice.