View Full Version : Technical Help Needed

08-03-2009, 09:28 PM
So here we are...day 1 of our 2 week vacation here on the Flathead Lake in Montana.

I have a 2004 XLV with the 340 HP Indmar. I know I have vapor lock issues but today was totally different.

Actually it started yesterday. Dropped the boat in the water and the kid took it for a "bit of a stretch" as he likes to call it. Went hard for about 5 minutes and then pulled into the slip at the place we rented. Approximately an hour later we went to go and the boat wouldn't start. Giving all the signs of vapor lock (start, quit, start, quit). Waited moire than another hour (trying periodically) and all of a sudden it went. We headed out on the lake, played for about an hour, starting, stopping, idling, etc, with no problems.

Today we hit the water around 12:00 noon. Pulled out and headed across the lake at a pretty good clip (about 25 mph). We cruised at that speed for about 45 minutes until we reached the other side. Shut it down for a bit, had a drink and then decided to do some surfing.

Now we have learned from you fine folks on this forum how to beat the vapor lock issue on the 340 HP Indmar. We run the blower all the time and as soon as we stop we always lift the engine hatch. I've even wrapped the fuel pump with a cold towel. So far this season we haven't had a problem.

This time, like the night before, it was giving symptoms of vapor lock. Again we waitied (trying periodically) and after close to an hour and a half of floating around it all of sudden started and ran strong.

So we headed immediately home, crusing for about 45 minutes until we reached the other side. We pulled up the throttle to idle and the boat started to labour, run rough and eventually die. This time we tried everything and after 2 hours pretty much gave up (the engine bay was cold and the only thing hot was my temper - because you have a boat load of people).

So I looked for the nearest shore and decided to dig out the paddles. However, prior to doing that (and I admit it wasn't smart and more due to the fact I was mad as hell) I started doing the start (it would run for a few seconds) and I'd put it into gear before it died. This would give me a couple turns of the prop each time before quitting. I continued this for about 20 minutes, moving toward the shore a few feet every time, when all of a sudden it started, ran strong, and took off like nothing happened.

I know the Moomba owners and this forum have been great for me and I'm hoping someone has a solution for me. I don't know if it's vapor lock, bad fuel of something wrong with an aftermarket fuel flow meter (Navman) the previous owner added.

HELP, HELP, HELP - thinking of pulling it out of the water and heading into Kalispell hoping a local marine shop might help.

Anything you can suggest to salvage this vacation will be great.


08-03-2009, 10:44 PM
there's an additive that you can buy, either from a marina or maybe the local auto store that helps the ethanol-blended fuel. kind of spendy but worth the try to as you say salvage the vacation....
really sounds like vapor lock, but maybe a filter? if you have the 1hr and tools, might want to change it out.
last time it happened to me, I dumped 3/4 bottle of water(the 16oz dasani kind) directly over the fuel pump, located on the left side of the engine and it went away immediately. blower all the time and lid up when parked on a hot day has fixed it for me.

good luck...
flathead is beautiful.. lived there for a year. side note, did the guy finish the big house on the island just off the shore of lakeside? he had seaplanes that pissed everyone off as he flew in and out in the middle of the night...
montana bar and grill just ouside lakeside and mooses saloon in kalispell ftw :)

08-04-2009, 12:13 AM
Thanks for the suggestions, I'm going to try both.

We got back to the house around 6:oo PM and had dinner. Went out to try and start it (remember it was running fine and we made it home) and it did the same thing again (start then quit after a few seconds). The boat had been sitting in the slip for almost 2 hours. I just went out to cover it up (it's now 10:08 pm) and it fired up and ran like a top.


The house on the island is actually where we went when we cruised across the lake. Still under construction with lots of equipment and activity going on. I can't tell the difference from the outside so it must be all interior work. Quite the palace for sure.

Thanks again


08-04-2009, 09:09 AM
It sounds more like a fuel pump issue. When my boat vapor locked, it did not start at all. The engine just turned. The boat was new and I did not know what it was. I would take it in to the dealer and have them check it. It could also be the fuel filter. How long was the boat sitting without beeing used? Did you use Stabel in the gas tank? When was the last time the plugs were changed? I am just trying tonarrow down the problem.

08-04-2009, 09:27 AM
Mine was the winter blend fuel. Once all that was out, it ran fine although when it happened to me, it would not start once it ran rough for a few seconds since the vapor was in the fuel rails. On a carb, I don't know how I would go about narrowing it down. To me, it sounds like the fuel pump. Good luck.

08-04-2009, 03:18 PM
I'm with Tazz here. Sounds like a bad fuel pump. It shows these characteristics.

Starts in the AM - after its been sitting for a long time.

Runs great for 1 to 2 hours or shut off.

Has to sit for 1 to 3 hours to restart again.

Then the cycle starts over.

Vapor lock isn't this predictable.

Sounds like the fuel pump is running hot and as long as its pumping it stays running and when you shut it off its over heats, as the fuel is what keeps it cool internally.

Id be looking at getting the fuel pump replaced and might as well toss in a fuel filter since its a new pump.

Sorry to hear your having issues while on vacation =(

08-05-2009, 10:12 PM

Hope you got your situation resolved. There is a new Moomba dealership in Kalispell. Kurt's Polaris is the dealership(no relationship). I honestly don't know what the experience level of the techs are. They are the Nautiques dealer as well.

Best luck,

08-05-2009, 11:40 PM
Hey if they are a Nautique dealer then you can have them install the PCM fuel pump system that according to some local expert is 10 times better than the Indmar system and was designed to eliminate the vapor lock issues they had years ago!
Ok i got a lecture about that from an Indmar AND PCM certified tech with MANY years experience! I have to admit trying to make allowances for a bad design is not how to sell boats.
I think we need to start putting some data into Excel here, I want to know and compare how many DD's vs. V-drives are having this problem. I am thinking there is something to this also. Who wants to put up the poll? Sled, Moombadaze, Kaneboats? And this is not a us vs. them issue I think there is something here as I don't see many post with the DD's having the problems and as hot as it gets here we have never experienced it.

08-06-2009, 10:28 AM
I haven't heard of it with a DD yet.

08-06-2009, 06:11 PM
Z, I'm with KB on this one, never heard of a DD getting vapour lock. I know just another feather in your cap for the Ultimate crossover boat quest. As you know I'm with you on this one anyway:)

08-06-2009, 07:27 PM
I'll second that motion.

08-06-2009, 10:41 PM

I brought up this issue with Jody (Florida Inboards) a year ago and he was well aware of it too. Remember he works on Ski Natiques and MasterCrafts and has for over 20+ years. He is also certified by both. He showed me the fuel pump layout on the PCM motors (ski tiques) after he showed me ours and explained how they did a great deal of work to eliminate this problem and is ahead of Indmar on this issue. They did not look anything alike and they both are running Chevy small blocks.
So while I have seen this issue on this board often I don't recall anyone with a DD complaining so there is a fuel pump location problem if this is the case. Somewhere there is more heat in the V-drives, maybe it is a v-drive packaging and ventilation problem and is not Indmars issue but SCs? I mean I can't yell at Indmar because mine always starts up fine (DD), anytime anywhere.
Whatever the issue I would not be happy if I had to perform a certain ritual to get home. I would NOT want to have to WORRY about performing a Ritual to get home! I would just not want this to be an issue on something I spent over 35k on! It should be the hottest thing on someones to do list!!! OK hint hint here people (SC, Indmar), BenchMark your competitors, sneak a peek, test one out, ask questions!!

08-07-2009, 07:44 AM
Is it both the 325hp and the 340hp motors having this issue? If not is it the cats on the 340hp causing the xtra heat in the engine area? as I could see that being a issue.

what model v drives? older lsv's and outback V's?, 06 and up lsv's?, or xlv's--there all v drives.

08-07-2009, 07:55 AM
Being loyal faithfull Moomba owners I think we should start helping out. We need some data collection!
Then we can plot it later and see where the issues lie!
Oh man I just looked at the clock I have to leave for work now!

08-07-2009, 04:36 PM
Hi gang, thanks for all the advice and feedback. Having laptop issues with no high-speed wireless and relying on an aircard that's kicked me out the last few times I've tried to reply.

Here's what's happening.

Went into Kalispell on Tuesday and popped into three different boat dealerships (I just noticed the Moomba dealer yesterday and was going to pop in today). All three agreed it was fuel related or vapor lock related. I came back home with an arm full of fuel additives, octane boosters and fuel stabilizers. There was a debate on methanol, with some suggesting using regular (89 octane) and others suggesting only premium (92 octane).

Filled up the gas cans with premium and dumped in about $20 worth of additives. We then found a couple pieces of 4X4 and placed them down the sides of the front edge of the engine compartment. It created a nice large air scoop to get the air and cooling we thought the engine probably needed and we could still use the sun deck.

Headed out Wednesday in 80+ degree weather and we played pretty hard for about three hours. Thought we had it beat. Then, like before but under power this time, the motor started to stall and gave the symptoms of running out of gas (quitting to full power to quitting to full power). Headed toward the shore ASAP and when we powered back to enter the no-wake zone it actually ran OK. Parked the boat in the slip, opened the engine compartment and poured ice-cold water over the fuel pump. Started the engine again and gave it some higher rev's while in neutral. Seemed to run strong.

Loaded everyone back up and headed out to the lake. Started tubing with the kids and after about 20 minutes the same symptoms again. Made it to shore, shut it down, covered it up, poured gas over it and tried to light it on fire (kidding).

Yesterday we poured in another $20 in additives, topped up the tank with premium and headed out. Almost identical scenerio with us getting about three hours of use before failure.

It's raining today so I'm going to head into the Moomba dealer.

So based on what's happening, is it fuel pump failure or vapor lock?

Thanks again for all the help. Most of the dealers are booked solid for the next week so I might have to guage the boat use on a 2 to 3 hour maximum daily use, which is really frustating (had a V-8 inboard sterndrive for more than 10 years before the kids pressured me into a comp boat V-Drive. Never had a problem).