Fuel supply: One line or two?

[PolarisNut]

I am getting everything in order to install some aftermarket Mikuni carbs on the TX. The question is, can I feed them with one 65 l/hr external pump and one pickup line, or will I definitely need two? Several have said one is fine, others have said two are required. Some say one is fine if you remove the stock fuel/water separator. Another option is two of these pumps Y'd off of one supply line, with two separate pulse lines. These carbs were originally setup with two of these pumps and two supply lines w/ a return jet...a bit overkill for a motor under 200hp, if you ask me. I'll easily be able to tell as soon as I run the boat, if it has enough fuel, by measuring the fuel pressure, but if it requires a second line, all of the pipes have to come back out to drill the tank.

[beerdart]

Does your fuel sender have reserve?

[ph2ocraft]

My basic Matrix 200HP has been running on a single line since 04, NOT one issue ever!
My SLTX has been running on ONE supply line as well, no issue and yes it does have the stainer installed, NO issue. I did switch it to the second line for awhile just to monitor and test things. I went back to the single line just for testing and got to lazy to switch it back.
I did run the trippple supply lines on the stage II as I've always had some fuel issues.
It didn't help but I have found my problem has been poor octane choice and I'm correcting that now.
My dollars worth is the extra line is safe but not required from what I've seen.

[PolarisNut]

Does your fuel sender have reserve?

Unfortunately the Virage has an odd-ball sending unit...no reserve. I have a twin supply sender for an SLX/Pro, but it wont fit the tank.

I currently have plenty of flow with the Keihins, I'm just a bit nervous about the bigger carbs requiring more fuel, and the single line not being able to supply it.

Here's some calculations, for S's & G's...I would wager a guess that a safely jetted PWC engine has a BSFC of about .65.

So thats .65 lbs of fuel per hp per hr...so .65*(we'll say 175hp)=113 lbs of fuel burned every hour. Fuel weighs in at roughly 6.5lbs per gallon I think...so 113/6.5=17.4 gallons per hour. That pump can supply about 17 gallons per hour...hmm.

[beerdart]

On the SLT 785 Project I pluged the reserve port in the side of the sender and put the hole out the bottom for two pick-up's.

[CrazyA]

I've got a few comments on this.... but I ain't touching it with a 10ft pole!!!



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[ph2ocraft]

C'mon Artie, you want to say it takes the extra fuel to be safe!! I agree, I've been getting away with a single feed line forever and I DO know better BUT the facts are, I've successfully run these boats all this time on a single feed line.
Keihins NOT Mikuni's, which require much more fuel!!!!

[CrazyA]

C'mon Artie, you want to say it takes the extra fuel to be safe!!

Now hold up a minute, not necessarily. (sp) I now have reason to think that there are pro's and con's to doing it either way, even though I've preached (hard) multiple feeds for a long time. Life is a learning curve.

I agree, I've been getting away with a single feed line forever and I DO know better BUT the facts are, I've successfully run these boats all this time on a single feed line.

And I absolutely know this to be fact, and I believe it.

Keihins NOT Mikuni's, which require much more fuel!!!!

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[ph2ocraft]

You're in at 11 feet, be careful.

[CrazyA]

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