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Hard start condition after running on a HOT day


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Hey folks,

I've got a unique (maybe) problem for you. First off, I've got a Hammerhead 383 (2004) in my boat.

Description of problem

My boat either won't start or starts and barely idles after I've run the motor for a bit, then let it sit for a period. Say 30 minutes or more. I talked to a couple people and they thought is might be vapor lock. Their suggestion was:

1) Cool down fuel pump by holding ice on the casing

2) Replace fuel pump.

Since this problem started mid-season last year (and a new fuel pump is $300!), I used the ice trick for the remainder of the season. At the beginning of this season, I replaced it. Everything was fine until the temps got into the 100's, then the vapor lock rear it's ugly head again. So, it's clearly not the fuel pump. Well, it's not the only problem, I should say.

Weird thing is, until last year, this has never been a problem. It only happens when it's REALLy hot. the motor always starts right up and runs fine in the morning...or evening. And the ice trick always works. Although, not really convenient. Especially when I have no ice.

Which leads me to two conclusions:

1) It's clearly temperature dependent

2) Something change last year to cause this condition and it's not the fuel pump.

The gas I'm using has come from the same station for the last 4 years. I did manage to find a station with pure gas, as opposed to 10% Ethanol. That didn't seem to make a difference.

So 'crew, any ideas?

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need a little more info....

when you say wont start... you mean not at all?

and when you say barely idle.... you mean a rough, knocking idle?

silly question, but have you tried to completely remove the keys, and then put them back in a try again?

i just went thru this on mine, not as bad, and found it has something to do with electrical/computer/fuel/igntion to turn off completely, rather then to leave on and start with having LEFT the system ON the entire time.

Leave the system ON for 7 hrs= 5 full seconds of cranking

reboot the system = immediate start

Edited by nyryan2001
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The compete ignition cycle does help as it toggles the fuel pump to repressurize the system.

If that does work then you may have a small leak somewhere on the high pressure side of the pump. A spray bottle with a drop or two of dishwater soap will help look for the leaks. Could be very small, may even be a leak internal to the system. When you toggle the key to the ON position ( without starting the engine ) listen to see how long it takes the fuel pump to pressurize the system. It sould only take one or two seconds.

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need a little more info....

when you say wont start... you mean not at all?

and when you say barely idle.... you mean a rough, knocking idle?

silly question, but have you tried to completely remove the keys, and then put them back in a try again?

i just went thru this on mine, not as bad, and found it has something to do with electrical/computer/fuel/igntion to turn off completely, rather then to leave on and start with having LEFT the system ON the entire time.

Leave the system ON for 7 hrs= 5 full seconds of cranking

reboot the system = immediate start

i doubt its vapor lock. vapor lock wont even barely let you turn over the engine

Some times it will start and immediately drop to 300-ish rpms (IE, barely running). If I pop it into neutral and try to rev the motor, it just stalls out. Or struggles to maintain RPMs.

I have definitely cycled the key. Although, you've given me a thought. I haven't attention if we've been parked and just running the stereo. Maybe if I pull the key out and 'reboot' as you suggested, that might help things.

If it's not vapor lock, what am I effectively doing by 'icing' down the fuel pump?

The compete ignition cycle does help as it toggles the fuel pump to repressurize the system.

If that does work then you may have a small leak somewhere on the high pressure side of the pump. A spray bottle with a drop or two of dishwater soap will help look for the leaks. Could be very small, may even be a leak internal to the system. When you toggle the key to the ON position ( without starting the engine ) listen to see how long it takes the fuel pump to pressurize the system. It sould only take one or two seconds.

High pressure side...is that the side that comes out of the top of the pump? It's a hard line going in and coming out. I suppose I could double check the flare nuts....

I've definitely heard the fuel pump pressurizing the system. Never paid attention to how long.

Another thought just popped into my head. Could it be electrical? I'll need to pay attention to the fuel pump, but if I don't hear it pressurizing, could there be an issue with getting power to the pump when it's hot?

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Intense- yep, try completely removing the keys after floating for a while and put back in a crank that way.....give it a try and see if the same problems replicate.

I say reboot on mine because ours have no keys, its a touch screen with a pin # to start, so more like an Iphone. All the guys kept telling me to take the keys out... I kept telling them I didnt have any.... I completely turned the entire sytem OFF 100% black, dead floating boat == immediate crank start!

what are you doing with the ice? i donno. cooling the fuel pump is only part of the equation... the fuel in any of the LINES leading to the engine could be turning to vapor also if they get hot enough...not just the fuel in the pump.

have you been tracking your engine temps while running... and then what they doo when you stop, and float? what do the engine temps do over the next few hrs??? IE how much do you run your blower?

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Intense,

I've got a Monsoon 325 in my 2001 VLX, but I've been fighting the same demons for a similar period of time. The issue only happens on days where the air temperature is extremely hot. So far, I've changed out both fuel filters, the fuel regulator and the fuel pump. I have to put a cool rag or ice on my fuel pump and cycle it at least 5 times, sometimes 10 times before it will start and idle properly. I turn the boat off completely and allow the fuel pump to cycle from scratch. For me it only happens after running awhile (30minutes plus) on a very hot day. Otherwise the boat starts and runs like a beast. Once I cool the fuel pump down it will run without any issues. I'm Interested in anything else you may have tried. I've got some TC's and an IR gun I'll begin monitoring the engine temp and post what I'm seeing. Perhaps I'll put a TC on the fuel pump and one on the block.

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I had much the same issues with my 325 Indmar and after replacing the fuel filter, running Star-tron (made by StarBrite) to break down the crud/moisture in the fuel tank and running the blower as much as possible I pretty much got rid of the problem. I think after 4 years the E85 finally took its toll in the tank and the moisture started to do the dirty in the fuel system.

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Prime example of vapor lock. You don't have to use ice, a large rag or towel draped over the pump and the connected fuel lines, dump some water on it. I can be back up and running in less than 10 minutes.

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Had the same problem. After running awhile when I stop I leave the blower on for 10 min maybe more. I haven't had the problem since. Also you could restart the engine a couple minutes after you stop to get some fresh cooler water in the engine.

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Some basics that may be known but worthy of review: fuel pump pumps liquid fuel thorugh the rails to the injectors. The injectors inject a mist which is dependent on there being adequate pressure in the fueling system. The fuel, in a vapor lock situation, has been thinned to a liquid vapor and the pump can't "grab" it. That can be exascerbated by fuel contaminants that vaporize at a lower temperature. Therefore you have no fuel pressure. That's why when the pump and nearby lines are cooled, the vapor condenses back to a sufficient liquidity that the pump can work. That's why you have no problems in the am. So, the goal has to be either keeping the lines and pump full of "cooler" fuel, or use a fuel that is less susceptible to the problem. It is generally regarded that non-alcohol fuels are less susceptible. If a blended fuel is all thats available, many people report success with using ethanol treatment. If it still occurs, I would suggest looking at insulating the fuel lines from the heat of the engine.

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Don't bother with the fuel pump kits to keep the fuel flowing just open the engine compartment and wait, but always run the blower. My problem with vapor lock was fixed most easily by using pure gas, instead of the crap some of these stations fill with ethanol and water.

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It's vapor lock.

Run the blower a lot.

Cold wet rag on the fuel pump.

Insulate the fuel rail & lines.

Good luck.

How would you propose I insulate rail/line and/or pump? I'm curious to hear what others have attempted.

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Don't bother with the fuel pump kits to keep the fuel flowing just open the engine compartment and wait, but always run the blower. My problem with vapor lock was fixed most easily by using pure gas, instead of the crap some of these stations fill with ethanol and water.

I tried pure gas, as opposed to an Ethanol mixture. But the problem persisted, although that may stem from the fact that I only did 3/4 of my tank with pur gas. And pure gas (around me) is about $0.50/gal more expensive.

I'm going to try that Star*Tron stuff to see if that helps to resolve my problem.

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I tried pure gas, as opposed to an Ethanol mixture. But the problem persisted, although that may stem from the fact that I only did 3/4 of my tank with pur gas. And pure gas (around me) is about $0.50/gal more expensive.

I'm going to try that Star*Tron stuff to see if that helps to resolve my problem.

I used to mix 93 (25%) and 87 (75%) too that helped a lot instead of using crappy 89, I can't tell you why, but someone a long time ago recommended that to my family.

Edited by mnhays
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How would you propose I insulate rail/line and/or pump? I'm curious to hear what others have attempted.

I bought a kit from Skidim.com. It was basically tubes of insulation. I had to break the fuel lines in a couple places, slide the insulation on & reconnect. Worked like a charm on that boat (1994 MC 205).

On my current boat (05 Vride with the Monsoon) I just run the blower a lot. It's only done it once & I'd forgotten to run the blower. I put a cold, wet rag on the fuel pump, and ran the blower & it's never done it again.

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