SoCal Jet Boats

Tech Talk => Engine Mechanical / Electrical => Topic started by: two6dogg on January 16, 2009, 10:30:24 PM

Title: marine carb VS street carb and other stuff
Post by: two6dogg on January 16, 2009, 10:30:24 PM

I bought a new 750 double pumper marine holley, Did I make the right choice? I notice alot of jet boats are running regular carbs. My dad had an old tahiti jet that would get beat up by lake mead chop and always flooded the carb. I also switched to an HEI set up instead of points, Was that a good choice ? any info would be great. I almost forgot its a 23' sleekcraft daycruiser, w/460 panther jet (yeah I know dont clown on the panther jet to hard).
               

Title: Re: marine carb VS street carb and other stuff
Post by: beerjet on January 16, 2009, 10:34:45 PM

You made the right choice for an enclosed engine compartment .

-beerjet-

Title: Re: marine carb VS street carb and other stuff
Post by: TyWannaBahna on January 17, 2009, 08:40:53 AM

Hey Beerjet- you mind explaining why a marine carb is better suited for an enclosed engine compartment?
And is it possible to use a street carb with the correct scoop, bilge blower, venting etc.

Thanks-Ty

BTW- I don't have an enclosed engine, but do have a street carb, just lookin for some education

Title: Re: marine carb VS street carb and other stuff
Post by: TyWannaBahna on January 17, 2009, 09:25:46 AM

Alright after a little research I would like to change my question

I now understand the flooding problem and the fire/spark arrest qualities of the marine carb

So do I need to get one, even with a open engine?

I have not run this boat yet and would rather fix problems now than later, That and fire doesn't sound that great in a boat that could be full of kids

Thanks for the help
Ty

Title: Re: marine carb VS street carb and other stuff
Post by: Nordie on January 17, 2009, 10:54:45 AM

personally if the engine is open i wouldnt really sweat it...n fmes are going to accumulate with an open hatch...no matter what you half to run a spark arrestor, well not half to but they will give you a ticket...with a doghouse over the motor i would take all the precautionary measures...remember that blower motors are your friend too...i would hate to be on a lake when your boat was suddenly going to catch fire...also for the marine carb question...you must remember that even altenators, starters, and distributors create spark and should be of the marine grade<~~~especially with a doghouse

Title: Re: marine carb VS street carb and other stuff
Post by: TyWannaBahna on January 17, 2009, 11:11:43 AM

Thanks Nordic

For what its worth I'll probably just get a marine carb, but just to make sure I got this right marine grade for

1. All ignition parts including Alt.
2. All fuel parts
3. All exhaust parts

but as far as the actual engine goes street parts are fine

Thanks again

Title: Re: marine carb VS street carb and other stuff
Post by: SkyHarborCowboy on January 17, 2009, 12:12:03 PM

I have always used street carbs on my Open Engine boats but I get some fuel line and make a loop from bow vent to bowl vent and put a hole in it  to gove over the Flame are arrestor and then two other holes right over the throttle bores in the event of a stuck float.  Other wise you take a chance of puking fuel all over the place.  In a car you can pull over and get out, in a boat you are going for a swim!

Joe

Title: Re: marine carb VS street carb and other stuff
Post by: beerjet on January 17, 2009, 12:54:59 PM

There is absolutly no harm in using Marine rated equipment in an open engine compartment .
The price is higher though .
These boats originally never came with "marine" equipment , but with enclosed engine compartment , I have taken the extra step to make as much of it USCG freindly as possible .
Nordie pretty much nailed it .
In an open engine compartment , fumes which are the major issue , arent the issue so much .
Carb flooding and tuning should always be checked first anyways , so secondary (for me) on my list of safety hazzards is fumes . I've always liked to put the boat in the water with the engine hatch open .
That lets it air out quikly and not to mention , when you start to crank it over , you can spot any other ptential problems like oil leaks , water leaks . fuel leaks , carb problems .
I let mine idle for a few minutes open and then cover it up once all checks out .

-beerjet-

Title: Re: marine carb VS street carb and other stuff
Post by: TyWannaBahna on January 17, 2009, 01:55:16 PM

Beerjet-

Thanks for the info- 

In regards to the flooding being "checked" does this mean that the flooding is not a result of say choppy water or sloshing/angling of the boat?

Obviously I will have the thing dialed in on land but CP performances site said that flooding and fire could occur even under good carb tuned conditions if it is not a marine carb, and I don't understand why, is that correct?  (I could see how they want to be "by the book" AND sell more marine parts)

If I can safely run my street carb I would just assume do it, but i mean extremely safely ya know

Thanks
Ty

Title: Re: marine carb VS street carb and other stuff
Post by: beerjet on January 17, 2009, 02:04:04 PM

I could see that .
I would make sure that the float levels are set properly .
I dont think you'll have a problem .
I ran through some nasty chop and my Mighty Demon never had any problems .

-beerjet-

Title: Re: marine carb VS street carb and other stuff
Post by: SLCKREG on January 26, 2009, 07:47:55 PM

I wonder if you can buy the j tubes that come in a marine carb and just swap em out? ???
I also heard marine carbs had a special powervalve in em(harder to blow up I guess?)  I dunno. I bet the J tubes would fool the ramp patrol.