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Fuel lines from gas tank, what is the red marked line?


stonelx

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I experienced the dreaded hesitation today while pulling a skier out of the water. The boat would accelerate normally, then kinda slowdown half way through pulling the skier up, but then eventually

it would go normal. Driving at full slalom speed there was no problems. Only when tromping the gear shifter would you notice the hesitation. The boat ran fine once up to speed.

At first I thought it was the Perfect Pass, but then it happened again and again. I double checked the PP, and it seemed fine. Even turning the PP off, and having no skier, the boat tromped

from just "in gear" would accelerate, then hesitate...and then go normal.

Ok, so this sounds like a fuel starvation problem. hmmm fuel filter?. When was the last time I replaced it?

OMG, too many years ago. (Please don't flame me) :)

So, off it comes, and I've just picked up a new one. (I hope that is the issue with the hesitation, could it be anything else? Perhaps a clogged screen in the fuel tank pickup line somewhere?, or worse?)

 

Anyway, after looking at the fuel tank while pulling off the fuel filter, I see two fuel hose lines. One has a regular silver fitting where the fuel filter is inline with, and there is another one

that is painted red. What is this "red marked" fuel line for? I can't tell where the hose goes. I will take a pic once I get back out there to install the new fuel filter.

Thx.

 

 

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@stonelx:  if 2 lines at the fuel tank fitting, one is supply & other (typically 5/8" diameter) is vent line.  Normally, anything clogged such as the filter or perhaps a sticky anti siphon valve (on the vent line at the tank) would show up at speed or under high fuel delivery conditions.  It also could be vapor lock if there is sitting time between the pull ups although vapor lock tends to be difficult starting and does not happen a lot if the boat stays running. 

Your symptoms do sound a lot like the PP unit unwinding or trying to find correct position, have you checked to see if the rope is tight, the servo & cable are free or the rope is wound backwards on the servo?  Good thought on checking that aspect.

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30 minutes ago, Woodski said:

@stonelx:  if 2 lines at the fuel tank fitting, one is supply & other (typically 5/8" diameter) is vent line.  Normally, anything clogged such as the filter or perhaps a sticky anti siphon valve (on the vent line at the tank) would show up at speed or under high fuel delivery conditions.  It also could be vapor lock if there is sitting time between the pull ups although vapor lock tends to be difficult starting and does not happen a lot if the boat stays running. 

Your symptoms do sound a lot like the PP unit unwinding or trying to find correct position, have you checked to see if the rope is tight, the servo & cable are free or the rope is wound backwards on the servo?  Good thought on checking that aspect.

Yes, the servo was good, and the throttle swivel was good too. The symptom of the hesitation is only out of the hole. I had about 1/4 of the winter gas left. (Burning the first 3/4 of the winter full tank had zero problems)

Dumped in 10 gallons, and the problem started that morning.

It's funny how the auto parts store guy looks at you when you show them this massive fuel filter. They're like... "What is this for?"

I tell them for a tow boat. "Oh, I see". 

But they had the part. So cool. :)

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@stonelx:  a clue may be the adding of 'new' fuel, hopefully it was not contaminated.  By adding fuel you might have stirred something in the tank (perhaps water or debris) that is now going through the system.  Winter fuel is a different blend and in particular is less resistant to vapor lock so were the temperatures higher recently that might have led to some issues, except with additional newer summer fuel that should have lessened that potential.  Hopefully, the filter is the issue.

I was going to consider that boat attitude might be part of the issue, at the point you seem to have the problem, the boat most likely is at the most nose high pitch.  What engine configuration do you have (Indmar ?, and is it EFI or carbed).

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On 7/19/2016 at 8:40 AM, Woodski said:

@stonelx:  a clue may be the adding of 'new' fuel, hopefully it was not contaminated.  By adding fuel you might have stirred something in the tank (perhaps water or debris) that is now going through the system.  Winter fuel is a different blend and in particular is less resistant to vapor lock so were the temperatures higher recently that might have led to some issues, except with additional newer summer fuel that should have lessened that potential.  Hopefully, the filter is the issue.

I was going to consider that boat attitude might be part of the issue, at the point you seem to have the problem, the boat most likely is at the most nose high pitch.  What engine configuration do you have (Indmar ?, and is it EFI or carbed).

I have the Indmar Monsoon 335 EFI.

Installed the new fuel filter today and voila! Boat ran solid!

Here's the pic of the gas tank with the fuel lines and new fuel filter.

 

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Edited by stonelx
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I had this same problem. Only happened intermittently but in the exact pattern you describe. Got a new filter from ibelonginprison and problem solved.  

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