View Full Version : Anyone having vapor lock issues?

06-01-2010, 03:53 AM
As if I didn't have enough problems on Sunday with hitting a rocky peninsula and doing damage to my prop and tracking fin I believe I was having vapor lock issues.
I've been out 4 times so far this year and I've had these problems 3 of the times.
I ended up having to be towed in just after dark after not being able to get the boat started for over a half hour.
Boat ran fine all day until I was headed back to the launch from where I hit the peninsula. I was a good hour away going about 30mph.
Boat would plane out fine and after running maybe 5 minutes it would bog, backfire and die. Go to crank and it would spit and sputter.
After I would let it sit a bit she would start right back up and then do the same thing all over again.
It also had a weird smell to it like she was running hot or lean. Temp gauge was right in the middle though.
I thought maybe it was a fuel issue so I disconnected the fuel line where it connects to the dual Holley lines.
I put the end of the line into a 20oz bottle and cranked the motor and no fuel. After cranking a few more times the fuel started coming out.
Hooked the fuel line back up and cranked the motor a few times and she would start right back up.
It then died again a short time later and that is when it would not start back up.
Floating in the middle of the river at dark isn't such a good thing considering there is alot of barge traffic.
I was still a good half hour away from the launch and there was a barge coming a few miles down the river.
Thankfully a passing boater stopped to help and ended up towing me through a back water of the river into a lake where there was a launch. Luckily the water was high enough to get into the lake.
As he was towing me I went to try and start the boat and what do ya know it started right up. I wasn't taking any more chances and told him to keep towing me to the launch.
I had a friend come and pick me up at the launch and drive me to get the truck and trailer which was a good 20 minute drive.
I was finally able to get the boat out and got home right around Midnight.
Such an exciting day !!!!!

I was wondering if anyone else has been having issues with vapor locking so far this year? I would imagine that the Summer blend of fuels is at all the gas stations by now.

I replaced the fuel filter on Saturday and also added a bottle of Seafoam and some Heet.

Yesterday I went to check the cap and rotor and the rotor seemed to be a bit burnt and the cap was a bit corroded on the inside. I went ahead and replaced them to be safe and used dielectric grease on everything.

Now what I'm trying to figure out is if this is a vapor lock issue, fuel issue, or an electrical issue.

I read over on Iboats of people having this type of problem and that it could be a bad coil so I went ahead and ordered one from SkiDim. The original one was still on the boat.

I also checked all electrical connections and nothing was lose or disconnected. Also checked the fuel pump/oil pressure safety switch connections.

Checked all the plugs and they were grayish/white (running lean?)

Floats on carb adjusted at correct level

I also went ahead and bought some of this tape and I'm going to wrap the fuel lines, fuel filter and fuel pump with it and hope it will help if it is a vapor lock issue.


Also bought be a new fuel line for the carb that has a pressure gauge built into it

http://cgi.ebay.com/ebaymotors/FUEL-INLET-LINE-HOLLEY-DOUBLE-PUMPER-4150-CARBURETOR-_W0QQcmdZViewItemQQhashZitem5188e6cc3bQQitemZ35018 9177915QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccesso ries

Sorry for the long post, but I'm just getting really frustrated with it.....

06-01-2010, 11:52 AM
Is your fuel pump the original one?

06-01-2010, 12:30 PM
Yes I ran into my first vapor lock on my second outing of this year. Ran the boat for about 2 hours no issues with start ups. Went to dock at friends lake house for about 1hr or 1 1/2hr. Came out boat cranked would just barely catch and then die. Poured cold water on fuel pump and line waited about 2min and started up right away. No issues for the rest of the day.
I Blame ethnol fuel! Found a place where we can get "no ethnol" fuel. Alittle more expensive but this should help problem. Hopefully you can find some. Its getting almost impossible to find ethnol free!

06-01-2010, 02:15 PM
My engine vapor locked on me once on saturday, took bottle of water from the cooler, poured over the fuel pump and fixed problem within 30 seconds. All you have to do is cool the pump down enough for the ethanol to get below the vaporization temp. 1st ime it happened to me I freaked out and almost got towwed in, but sat long enough for it to cool and worked fine. Since then it has happened a few times, but water always solves it for me. Just be patient.

Run blower constantly on hot days
Keep bottled water on ice in cooler, normally one bottle poured over the fuel pump solves the issue.
Open the engine hatch to allow the compartment to cool faster if possible.


06-01-2010, 06:55 PM
Different kind of fuel pump on an EFI vs a carbed motor (high press vs low press). Also, they operate differently.

You are probably experiencing your fuel pump failing. You will probably need to replace it. Assuming that you have replaced your fuel filter and the carb is adjusted properly.

06-02-2010, 01:23 AM
The fuel pump is pretty much new. I replaced it in the middle of 2008. It is definately working as when I disconnected the fuel line and cranked the motor it was pumping plenty of fuel.
I figured I might as well replace all the electrical stuff at the same time. (Coil, cap & rotor.) I think I might order some new plug wires as well. Not sure if the ones on there now are the original ones. (They are red.)
After reading more about vapor lock I had no clue about pouring water on the fuel pump.
I'm hoping that the heat tape I bought will do the trick, but I will have to wait and see....
I'm almost positive it was vapor locking. It always seemed to start back up after I opened the dog house and let it sit with the blower running for a while.
Such a pain in the ass though !!!!!
I think it's time to talk the old lady into upgrading the boat to one with EFI !!!!!!

06-02-2010, 09:17 AM
I've had vapor lock issues on my boat before and from what you described in your original post it just doesn't sound like vapor locking. If it's going to vapor lock, it should do it on the initial startup after it's been sitting, not after it's been running 5 minutes. Once the fuel is flowing it keeps the pump and hoses cool enough that it shouldn't vaporize. I'd lean more towards, the pump, filter, or bad gas.

06-02-2010, 09:49 AM
You can't assume a 2 year old fuel pump isn't the problem. I've seen plenty of "bad" brand new parts or short lived new parts in the last couple of years.

06-02-2010, 05:53 PM
Is there any possible way that I can test the fuel pump to be sure it is always running when the boat is and that it is running at the correct pressure?
I'm sure I could stick a test light on the power wire for it to make sure it is always running when the boat is.
I'm hoping this fuel line I bought will also be able to tell me it is getting the correct amount of fuel with the pressure gauge it has built into it.

http://cgi.ebay.com/ebaymotors/FUEL-INLET-LINE-HOLLEY-DOUBLE-PUMPER-4150-CARBURETOR-_W0QQcmdZViewItemQQhashZitem5188e6cc3bQQitemZ35018 9177915QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccesso ries

If it seems to be lacking enough pressure on the gauge then I'm assuming I'll need a new fuel pump... SIGH

06-02-2010, 06:18 PM
You should be able to get a pressure guage at a local auto parts store (or order that one from ebay), install and know what your pressure is at all times. IMO you get what you pay for, so get a "good" guage, so that you have accuracy.

06-02-2010, 09:38 PM
I am having vapor lock issues. Yes, pouring water over the fuel pump works, but is only temporary and the fuel pump still whines. Found that the solution from skiers choice is adding a second fuel pump before the fuel filter. 2007 models they are providing the fuel pump at no cost. Of course my 2006 LSV isn't covered, so I had to buy it. Has anyone tried installing this option from skiers choice? I started tonight but they provide a 90 degree fitting and I need straight of course.

06-07-2010, 01:57 AM
Well today I finally got the new coil put on.
Replaced the cap and rotor last week....

Also installed the new fuel line with the pressure gauge and I'm not too happy with the quality of it. I'm hoping it's not going to leak at all and it just seems very "cheap."
I guess that's what happens when you buy things on Ebay sometimes.

I also started wrapping parts of the fuel lines with the heat tape to prevent the vapor locking issues.
I went to try and start the boat and nothing.... Just cranked and cranked and cranked, but would not fire. Well great, what now?
Come to find out it doesn't seem like the fuel pump is working or is low in pressure.
It definitely had power to it...
Disconnected the fuel pump and lines and went ahead and ordered a new one from Summit Racing... $117 Carter P4389
It kind of makes me mad that this one is only about 2 years old and already crapped out on me.

I also got the OJ 13X12 prop I purchased from TL7 installed.
I had already ordered the 3 jaw puller from Harbor Freight Tools, but the prop came off by hand with ease for some reason.
At least I will have the tool now in case I ever need to use it again.

I had talked to a mechanic at the local marina the other day and he said to stay away from using Heet as it has a lot of alcohol in it and isn't good for the fuel system on a boat.
He said Seafoam is OK every once in a while, but he said to buy the Stabil Ethanol formula and to run that in EVERY tank and it should help a lot with the fuel.

06-07-2010, 02:54 AM
My brother the auto mechanic says that many of the people with high powered outboards are using that Stabil in the Lacrosse area where he lives. He says it's a good product.

06-07-2010, 11:17 AM
I am having this same issue for two seasons now. I am thinking about getting a water separator because this is happing too often. I do use a engine compartment heater which creates a greenhouse effect in my engine compartment during the winter. I store with stabilizer and a full tank but that does not seem to be working. Seems like I get a large amount of water in my tank.

06-10-2010, 12:11 AM
Got the new fuel pump today and had it installed within 20 minutes. I also wrapped some of the heat tape around it to prevent vapor lock.
Cycled the key a few times to get it primed then started cranking the motor and what do ya know the Ebay fuel line started leaking. I figured this was going to happen because it just didn't seem like it fit right....
Went ahead and disconnected it and put the old one back on.
Went to start the boat again and she fired right up !!!!!
Problem fixed... (For now.)
I guess I'm out $40 on the fuel line, but oh well it's only money right?
I'm going to order another the correct Holley one from Summit Racing that has the gauge port in it so if anything else goes wrong I can at least see if there is fuel pressure....

06-10-2010, 12:20 AM
I had vapor lock a few times last summer. Started using stabil for marine engines and it solved the ethanol/vapor lock issue. 1oz per 10gal I believe.