carburetors.....

[wiskebound]

after years of issues with the stock 2 bbl carb on a merc 5.7. im curious if i should replace/rebuild with stock or it would pay to replace it with something a little bigger? I know Holley produces a 300 and 500 cfm carb. and was thinking of going that way? Just wanted to know if anyone knows if this is a good idea or should i stick with the stock? thanks

 

[Bondo]

Re: carburetors.....

Ayuh,... Mercruiser has Never used a Holley on a Chevy based motor,...
That alone indicates potential Problems...

I'd either rebuild/ replace what you've got,...
Or,..
Go to a 4bbl. carb such as the Edlebrock Performer carb, which is a carbon copy of the Merc/ Weber that Merc has been using for the last 10 years or so...

 

[wiskebound]

Re: carburetors.....

thanks... the intake isnt a big changing issue to goto a 4bbl.. and im looking for a little better preformance anyway.
i would stick with the stock carb, but the stock carb has been giving me starting issues for years, either the floats are sunk?? or the needle seats are letting fuel by after i shut it off?? seems to flood out every time i turn it off and is a bear to start back up once the motor is warm..

 

[Kainon]

Re: carburetors.....

Up to you to either get it properly rebuilt or buy a New carb. They range from $150-$500 but sometimes a necessary evil.

Volvo Penta uses 500cfm Holley 2 carbs,

I dont believe Mercruiser went with Rochester & Webber Carbs because they perform better than Holley, heck, take a look at Racing Cars, how many have Rochester or Webbers, VS Holley.

But they all do the same thing.

If you really want more performance and a little better economy than even the 2bbl carb, go with a Holley Marine TBI Pro-Jection Kit.. though it will set you back a bit.

 

[Kainon]

Re: carburetors.....

ps.. OMC has been using them for a long time too.

 

[wiskebound]

Re: carburetors.....

thanks again..

question to kanion, the holley pro-jection? i see they are about 1K, not to bad... just curious, do you know if i need to change the stock intake from 2bbl to 4bbl?
i was told this was the way to go to rid of all the carb issues, its a few bucks and im looking to possibly sell next year so its got me thinking????

 

[haulnazz15]

Re: carburetors.....

Just get a 4bbl Edelbrock intake and the 1409 Edelbrock carb. They are simple and pretty much set from the factory to work on the 350 SBC's. While race cars, etc, may use Holly carbs to inch out that extra few HP, they require you to really know what you are doing in order to do so. Lot's of small adjustments in order to make an extra few ponies isn't going to pay off in the marine application. The Edlebrock will likely be a simpler solution and less of a headache.

 

[Kainon]

Re: carburetors.....

I've been on and worked on a few boats that have Holley 2bbl carbs and they perform excellent !!! I'm a GM guy and know the Rochesters/Merc Carbs.. pretty well, Holley still makes Marine carbs that are drop on tuning to.. not just Vic ( though it is a good solution it's not the only one ).

The 2bbl 275hp capable Holley kit is designed to bolt to a 4bbl intake either Squarebore (webber/Edelbrock/Holley) or Spreadbore ( Rochester quadrajet/Mercarb 4bbl ) it doesn't mention about 2bbl intake, and it doesn't look like from the pics that it does either.

http://www.jegs.com/i/Holley/510/700-21/10002/-1?CT=999

 

[wiskebound]

Re: carburetors.....

thanks to all..... i have been on other forums and never got such quick responses.... just ordered a edelbrock 650 carb and preformer intake.. A little more than a rebuilt stock carb but i hope a lot less headaches with better preformance in the long run.....

 

[Kainon]

Re: carburetors.....

You ordered the Marine version right #1409?

I'm only seeing 600cfm and 750cfm in the Marine version.

 

[wiskebound]

Re: carburetors.....

yeah, sorry.... its the 600 #1409.. i figured the 750 would be a little too much?
was right around $310.. and $200 for the intake from a local preformance shop which offered a online discount... im suprized it was cheeper locally then summitt or jegs...

 

[Kainon]

Re: carburetors.....

the 750 is more for big blocks or highly modified small blocks

 

[haulnazz15]

Re: carburetors.....

Correct, the 750 would be too much. It's mainly for suped-up big blocks/strokers. Even stock big blocks can use the 600cfm with no problem. I think you'll be good to go.

Kainon, I'm not arguing that Holley isn't a good carburetor, they are great. In my experience in the automotive world, they tend to take a little more knowledge to set up correctly. The Edelbrocks are slightly more simple and tend to hold their settings better. YMMV

 

[John_S]

Re: carburetors.....

yeah, sorry.... its the 600 #1409.. i figured the 750 would be a little too much?
was right around $310.. and $200 for the intake from a local preformance shop which offered a online discount... im suprized it was cheeper locally then summitt or jegs...

Just some additional misc stuff you will need:

- Fuel line
- throttle bracket
- flame arrester

Assuming you have non-vortec heads, consider blocking off the exhaust crossover passages. The 1409 is electric choke, and you do not need all that heat in the alum manifold. If vortec, no issue: there isn't any crossover.

Also consider adding a port instead of a plug (just behind carb) on the intake, to make for easy vacuum gauge hook-up and diagnoisis. Recommend painting intake before installing. You need zinc chromate primer followed by black (or other).