Carburetors...how many?

[dragonwolfe]

This may seem like an easy question to the guru's on the board, however since I am still a student at this,the finest school of high peformance outboarding. I can only ask for input from the gurus, our teachers.
The question, What is the performance increase obtained by efficiently carbureting each cylinder, as opposed to say one carb per 2 cylinders?
Does this performance increase create a dramatic increase in fuel consumption as well?
Thank you:D

[T-REX]

U actually are feeding each cyl with it's own carb, in a manner ov speeking...each cyl haz it's own venturi, in a sence it's own carb...A 2 bbl carb iz actually (on an OB) 2 , 1 bbl's together...Each side is tuneable seperate from the other, etc...corse I know U now this...Now, U kan build a manifolde that will allow U to use a 2bbl for each cyl(Big bore motors like them), or Merc had a front half that had 6 tillitsons on it, one for each cyl...But for the addition of a 2bbl per cyl, U better have it reedy to use a lot ov fuel and a drastic drop in intake velosity...It will(and does) work, but only on highly modified big bore motors...and Fuel economy, well either add anuther tank, or don't plan long trips;) ...REX

[Reese]

Having one carb per cylinder allows designers to create the most efficient path (short intakes), minimizing the separation of the air/fuel mixture while maintaining good throttle response.

2 strokes generally do not like long intake tracks, if we were to use a single carb to feed two adjacent cylinders the intake track would have to be twice as long and would require a rather sharp radius.

In order to minimize this radius problem we would have to extend the intake track even further out (kinda like a high rise on car motors) making it even longer (which 2's don't like) not to mention it would create clearance problems with the cowl.

Fuel injection alleviates many of the constraints…for example the single butterfly horn is possible because of it…of course engineers have taken this one step further by creating individually tuned intakes which is even better.

[dragonwolfe]

T-Rex, I have seen some of those big old inline six mercs with the six carbs on them and always thought it looked cool anyways.
Always wondered if there were any advantages to the extra carbs.
Thanks

[Superdave]

try these

[dragonwolfe]

I always knew a 12 pack was better than a 6 pack;)

[MODIFIEDOUTBOARD]

Took alot of work to make it work!

[sho305]

So how about my I6 1500 with 3 carbs....I suppose 6 are not cheap....and I'd need a guy who knew ports....and I might as well get a V-6?

[Travis Fulton]

:D

[Raceman]

I had one of those 6 two barrel setups on a Bridgeport. I never could get it tuned right. If it was right on top, it was miserable down low.

Sho, you'd better just make up your mind to like that 1500 like it is. There's nothing reasonable you can do to help it, outside of getting the setup right and doing all you can to make it last. If that doesn't scratch your itch you'll have to get a V6.

[sho305]

Hehehe...Looks like I might not be able to this year:( Bad economy hurts. Was thinking of finding a Viper for it so I can learn how to drive the hairy things; not had much wheel time on a small pad hull. Sound like a good idea? Crazy horse even says he can help me with air brakes:D

What do I need to change on it? I know I need a cleavor, likely a nosecone/LU too.

[Raceman]

I'd want dual cable steering and solid mounts would be helpful too. If you're gonna run a 20" 1500 on a Viper you'll need a jack plate, but I'd look for minimal setback.

[sho305]

Strange, on my Checkmate the new (but stored forever) cable was froze up but not rusty. So I lubed it and worked it, now it steers a little hard with the small wheel on it. I think it helps actualy, and it only wiggles when hitting a wake at an angle. But I want no part of that rubberband steering for this.

I hope to find one with dual steer and a jack in the spring. I'll need the mounts. I see on here it needs no setback, and a stern lifting prop appears to be better. Didn't know if I needed a short mid, or the best way to get a low water pickup/cone on that old thing I think I'll need. Looks like many Vipers have no windshield too, kind of a bummer when you run in 60 degree temps;)

I was also told that venting the cowl would not help power on this 1500 either. I did chop some of the foam off the front cowl cover anyway;) Just can not complain about that 1500, it has held its ground a long time. If I can find a use for it I might as well run it.

[Raceman]

I think the 15" mid would be much better if you can find one. Not only from ease of rigging, but the handling is definately better with it. You're correct that the louvered cowl doesn't help. It seems like it would. I even drilled 1 1/2" holes across the top front edge of the top cowl like the ones in the front of a T2 and all I got from it was a water logged starter motor first time it rained.

You're right, the old 1500's are tough engines when used right.

[sho305]

Thanks Raceman, think I'll be hunting that stuff down as soon as I finish my current auto project here. :rolleyes: That will give me some more incentive; one would think '92 F150 parts would be plentiful here....what a pain.