Vapor Lock, Replace Fuel Pump or add 2nd Low Pressure fuel pump?

My 2005 21V (350 hours) has started the dreaded Vapor Lock issues after getting hot and sitting. I can pour water on the fuel pump and the boat immediately runs normal. I have read about adding a 2nd Low Pressure Fuel pump to the fuel line as the fix... So I relocated my current fuel pump to near the fuel tank as a 2nd Low Pressure fuel pump would be located. This helped and cut down on the frequency of vapor locking but has not eliminated it. I feel like the current fuel pump is just about worn out because it is 6-7 years old and I have been running fuel with Ethanol. I wonder if I would be just as well off to go ahead and just buy a replacement for my current fuel pump and keep it located near the fuel tank. What do you guys think?

Anyone else done something like this to avoid the 2nd fuel pump?

Where is the best place to buy the fuel pump?

I found a fuel pump (Item# 55-6184) on Ski DIM .com for $313 that says it is for “ ’04 up Supra/Moomba” . Marine Parts Source .com has the same Item # for $277.52.

Is this the correct pump? Is there a better one that should be considered upon replacement?

Have you tried contacting Indmar? I heard they were offering a second fuel pump to people who were having these issues. They added the second pump on 2008 models to help eliminate this problem, on my '08 I never had any vapor lock problems, even in 110 degree weather. Might be worth a call to Indmar to see if you can get one for free or a reduced cost. This issue has affected many people pre '08 and older.

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Originally Posted by Fman

Have you tried contacting Indmar? I heard they were offering a second fuel pump to people who were having these issues. They added the second pump on 2008 models to help eliminate this problem, on my '08 I never had any vapor lock problems, even in 110 degree weather. Might be worth a call to Indmar to see if you can get one for free or a reduced cost. This issue has affected many people pre '08 and older.

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I have not called Indmar. I did call my local dealer and was told that Indmar might provide a pump at no cost to me but they would have to change me for Labor including testing. I figured I was just as well off to buy it on my own at that price...

Do you have a contact at Indmar?

My father has an 08' model and started having the issue this season but not once seasons past. We took it into the shop twice and they could not duplicate the problem and were confused sice it is an 08' and has the two pumps. So we were leaving for a week on the lake and went back and made them work on it until we figured it out! Finally looking at another 08' they noticed that the fuel filter was between the two pumps. My fathers boat had the filter before both pumps, so they changed the sequence to mirror the other boat and we havenothad a problem. So make sure the sequence is pump filter pump.

Zach, I saw your missed call and I am now having the exact same problem! I'll give you call.

I think I am going to start by replacing my fuel pump as I'm having issues even starting the boat now. Can anyone verify those are the correct part numbers?

Fman, it would be great if Indmar replaced them for free or reduced but I have the same local dealer as Zach and I'm more than hesitant to return.

Below is contact information I have found for Indmar. I called the 800 number, was transferred to customer service, and was told they have a 2ndary fuel pump they suggest (Part# S495137) that is only available by contacting your local dealer. I asked them about providing this pump at a reduced cost and I was told that I am about 3 years out of warranty so there was nothing they could do for me. I asked them if I could just replace my current fuel pump and was told the only way to know is test the fuel pump pressure which should be between 53-58.

1.800.238.7112

[email protected]

[email protected]

Vapor lock will usually occur during the "heak soak" cycle, between 5 to 90 minutes after shutting off the engine. The best way to avoid vapor lock is to keep the engine compartment cool. Sometimes consistantly running the blower to help with engine compartment ventalation will help. Some engine builders recommend larger fuel hose diameters with fewer bends. Running the blower before, after and during engine operation works great for me.

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Originally Posted by csleaver

Vapor lock will usually occur during the "heak soak" cycle, between 5 to 90 minutes after shutting off the engine. The best way to avoid vapor lock is to keep the engine compartment cool. Sometimes consistantly running the blower to help with engine compartment ventalation will help. Some engine builders recommend larger fuel hose diameters with fewer bends. Running the blower before, after and during engine operation works great for me.

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Thanks for the tips. I have tried running the blower at all times lately and that has not helped me.

Had the same vapor lock issue and this is how I solved it on my 2006 21V. I went trough the same thought process with the 2nd pump. The mechanic at my dealer said save your money and do this. I thought he was crazy because it sounded too simple, but I haven't vapor locked in almost two full summers.
1. Replace your fuel filter.
2. Always use mid grade fuel or better
3. Always use a fuel additive. I use Stabil for marine applications.
I'm in Atlanta and it's been in the 90's since June and haven't had the boat vapor lock once this summer.

Hope that helps and if it does it beats spending all that money on a 2nd pump.

Scott

Thank You Scott.

I've had the vapor lock issue on my '06 21v since the first time I took it out brand new. I've now got a 2 year old and a 4 year old and this is the first year we've been able to start spending a lot of time on the boat as a family. I guess that's what made me realize this problem for what it is instead of an inconvenience. It's a safety issue. My boat was bad enough that it was a given that it would vapor lock if we let it sit for a half hour or more after running it. Nothing help, running the blower, leaving the cover open, etc. A lot of that is because all of the fuel available here is 10% ethanol and the lake we are usually on feeds a power plant so the water gets pretty warm. It hit me while we were anchored up and the kids were swimming. What happens if one of them gets hurt and I need to run back to dock in a hurry? The last thing I want to do is work on a vapor locked boat in that situation.

I finally just went ahead and bought the indmar secondary pump kit on skidim. Install isn't bad at all. It took me a couple of hours but most of that was figuring exactly how and where I wanted to mount it, not actually working. I mounted it right to the stringer on the port side just aft of the fuel tank. The biggest problem I had was space between the v drive and stringer. It's pretty much impossible to get a drill in there to start the holes for the mounting bracket. If you've got a drill that you can get an angle drive attachment for that would work. I've got a cordless impact driver which was just short enough to get the job done. The included bolts for mounting the bracket aren't ideal either. They are machine threaded so they're not made to hold well in fiberglass. I undersized the holes a little bit and they are working fine so far but I'll probably swap them out when I find some small lag bolts that are stainless or treated so they won't rust.

So far everything has worked great. Not a single problem since the install.

Since I started using Marine Sta-Bil with every fill-up (after having to replace the fuel pump), I have had almost no vapor lock problems - in spite of the fact that it has been a really hot summer here.

I learned that the ethanol that they are putting in the fuel vaporizes and causes the vapor lock. Look for stations that use less ethanol in the fuel (if possible), add fuel stabilizers, and when you stop, open the engine compartment to vent it. One owner told me that he would soak a towel in the lake and wrap it around the fuel pump.

My boat had the second fuel pump added to it, and I don't have any problems (as of yet, knock on wood) with it vapor locking.

I have recently put the fuel pump through a heat soak period on a couple hot days and had no problems. I know this is a old issue from last summer but I just had a chance to really test my aplication on hot days. I relocated and replaced the exiting fuel pump and have had no problems since then using the cheapest gas I can find.

I would like to know how vapor lock (supposedly) is so prevalent in boats with fuel injection? I understand that the fuel possible could vaporize in the fuel line but with a electric pump. It should self prime quickly and clear up. No differently than running out of gas then putting gas in it. Cars would be on the side of the road all through the southern states. I don't get it.

I don't know how to answer your question… other than I know what fixes it. Someone on here probably will... I know how to fix this problem but cannot swear to what causes it other than a “heat soak” period. All I know is pouring cold water on an old fuel pump that has been through a "heat soak" period will resolve the issue immediately and get you going temporarily. Replacing the fuel pump totally resolves the issue permanently... until it wears out again I suppose. I guess the fuel pump just gets worn out over time and losses it suction power... Maybe ethanol wears the pump out faster, maybe not.

I'm thinking your right. It's not the traditional "vapor lock" you see with carbed engines but a heat seam issue with electric components.

I had the same issue on my 07 21V so i went with a Bosch 044 fuel pump and mounted it next to the v-drive very little replumbing just the high psi line had one made at the parts store and no more issues. With the stock fuel pump mount on the motor it gets hotter than hell so I can see why everyone has issues.

Hmm - had this happen for the first time at Lake Powell last week 20 miles from NOWHERE ... the squirt gun cooling method stopped it, but I can't tell if
the pump is shot - it was an anomaly - had run hard at 30MPH for 1.5 hours in 105 temp, then sat for an hour -- then nothing until I "chilled" the pump a few times,
started and ran fine the rest of the week.

2008 240H Indmar Cat with the 2 fuel pumps to eliminate this problem, but it was HOT and I was pushing it hard.

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Originally Posted by tg0824SSVGG

Hmm - had this happen for the first time at Lake Powell last week 20 miles from NOWHERE ... the squirt gun cooling method stopped it, but I can't tell if
the pump is shot - it was an anomaly - had run hard at 30MPH for 1.5 hours in 105 temp, then sat for an hour -- then nothing until I "chilled" the pump a few times,
started and ran fine the rest of the week.

2008 240H Indmar Cat with the 2 fuel pumps to eliminate this problem, but it was HOT and I was pushing it hard.

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You could run the boat all day in those temps as long as you dont stop and let the "heat soak" process take place. As long as you are running the motor it stays cool enough for everything to work. When you stop, the heat starts to radiate from the motor because the motor is no longer being cooled my the moving water.

I replied to this thread earlier and I still have not had another issue of vapor lock. I was told the ethanol breaks down the fuel filter not allowing enough fuel to pass through. Not enough fuel passing through the line and high engine temps equals vapor lock. No vapor lock for almost three summers with this method.

"Had the same vapor lock issue and this is how I solved it on my 2006 21V. I went trough the same thought process with the 2nd pump. The mechanic at my dealer said save your money and do this. I thought he was crazy because it sounded too simple, but I haven't vapor locked in almost two full summers.
1. Replace your fuel filter yearly.
2. Always use mid grade fuel or better
3. Always use a fuel additive. I use Stabil for marine applications.
I'm in Atlanta and it's been in the 90's since June and haven't had the boat vapor lock once this summer.

Hope that helps and if it does it beats spending all that money on a 2nd pump."

Scott

I know this thread is old, but it seems like i have this issue. It looks like i have a 2 pump system. I just bought a new fuel filter hoping that is all it is. If problem persists afterwards, i'll check the fuel pump. I'll update after new filter installation.