Has anyone upgraded to a 4bbl carb on their Mercruiser 4.3

[jkust]

Hi all. I am considering changing out my stock 2bbl carb on my 2003 190HP Mercruiser to a 4 barrel EDELBROCK #1409 600 CFM model and highrise manifold. I understand I will likely need to up the pitch as well so will need a new prop. Here is the thing. It seems the advice I get is either that it will do little or nothing for midrange and top end as I want, or it will add 35hp. Does anyone have any real world examples of this switch? I read the article called "Why buy EFI when you can get more power for a lot less?" http://www.boatingmag.com/article.asp?section_id=8&article_id=501&page_number=1 It really sold me though they used a V8 not a V6.

Thanks for the advice.

 

[sleeper]

Re: Has anyone upgraded to a 4bbl carb on their Mercruiser 4.3

http://www.michiganmotorz.com/Marin...ur+barrel+Vortec+intake+manifold+(1996+-+2008)

Looks like a 20hp increase from changing the 2-barrel carb and manifold to 4-barrel stuff. Not sure it is worth the expense for 2-3 mph. I say go for it and let me know how it turns out for future reference. I have been modifying cars for years, but most will tell you its not really worth it on boats due to the little payback.

 

[oops!]

Re: Has anyone upgraded to a 4bbl carb on their Mercruiser 4.3

2-3 mph on a boat is lots if you use it.......

i havent done the conversion....but have thought about it.....if you really need the power......ie if your boat is a underpowered dog......then go for it....

but if you just cruise around at 1/2 throttle and dont nail it......all youll see is possibly a better mid band torque......plus if you up size the pitch on the prop....that might take away any advantages you might get from the increased bottom end.......

but this is all theoritecal.....as i havent done the swap

 

[wca_tim]

Re: Has anyone upgraded to a 4bbl carb on their Mercruiser 4.3

do a couple searches and find some of the threads on this. It's been covered in detail. a well tuned 4-bbl vortec v6 should make around 220 horsepower, and more torque than the 2-barrel version. The general con census is that there is a significant increase on the top end as well as a noticeable "seat of the pants" increase. I would say it is definitely an upgrade worth doing.

I didn't do the swap personally, but I did pick up a boat with a trashed 2-bbl v-6 in it and installed a new reman with vortec heads, 4 bbl, intake, etc, etc... and with some tuning, it performed really well... especially for a 6 cylinder.

 

[tashasdaddy]

Re: Has anyone upgraded to a 4bbl carb on their Mercruiser 4.3

i suggest this question be ask in the inboard/outboard forum. this is not an engine topic forum.

 

[wca_tim]

Re: Has anyone upgraded to a 4bbl carb on their Mercruiser 4.3

i suggest this question be ask in the inboard/outboard forum. this is not an engine topic forum.

err... um.... this is the i/o forum????

This is about the point where my daughter would say something about my declining mental faculties as I get older...

ps. you know people care when they take the time to give you a little grief once in a while...

 

[79Glastron]

Re: Has anyone upgraded to a 4bbl carb on their Mercruiser 4.3

600 CFM is too much for a 4.3. I suggest a 500 CFM carb.

 

[wca_tim]

Re: Has anyone upgraded to a 4bbl carb on their Mercruiser 4.3

nobody makes a decent 500 cfm marine carb. the best for a 4.3 for the monay and easy to set up is the edelbrock 600... Sure the engine probably doesn't need all of it, but they work great.

 

[Bondo]

Re: Has anyone upgraded to a 4bbl carb on their Mercruiser 4.3

600 CFM is too much for a 4.3. I suggest a 500 CFM carb.

Ayuh,...

The Edlebrock Performer, 625cfm, is a Carbon Copy, even the parts interchange, of the Merc./Weber used on the 4.3LX....

Mine has the Merc./Weber carb,+ I use Federal Mogul/ Edlebrock tuning kits,+ carb kits in it...
Much Cheaper,+ a Much Better Selection of parts than Mercruiser...

 

[jkust]

Re: Has anyone upgraded to a 4bbl carb on their Mercruiser 4.3

Ayuh,...

The Edlebrock Performer, 625cfm, is a Carbon Copy, even the parts interchange, of the Merc./Weber used on the 4.3LX....

Mine has the Merc./Weber carb,+ I use Federal Mogul/ Edlebrock tuning kits,+ carb kits in it...
Much Cheaper,+ a Much Better Selection of parts than Mercruiser...

So you think the Edelbrock Performer is the way to go. I did some more research and the Performer options seem to be either the 500CFM that the specs say is for the 4.3 v6 or the 600CFM performer that needs an adapater for the 4.3. I don't see the 625cfm version of the performer on Michigan Motors or Jegs. Also, I am now realizing that there is no such animal as the highrise intake manifold for the 4.3 v6. (I keep saying v6 because I found the parts for an old 4.3 v8> I see they are making it hard to bolt a few mods on cheeply. Am I just missing something?

 

[MikDee]

Re: Has anyone upgraded to a 4bbl carb on their Mercruiser 4.3

do a couple searches and find some of the threads on this. It's been covered in detail. a well tuned 4-bbl vortec v6 should make around 220 horsepower, and more torque than the 2-barrel version. The general con census is that there is a significant increase on the top end as well as a noticeable "seat of the pants" increase. I would say it is definitely an upgrade worth doing.

I didn't do the swap personally, but I did pick up a boat with a trashed 2-bbl v-6 in it and installed a new reman with vortec heads, 4 bbl, intake, etc, etc... and with some tuning, it performed really well... especially for a 6 cylinder.

I missed this thread earlier, but I'm with wca_tim, I say better distrbution of fuel with a 4bbl, and your engine doesn't have to work as hard to draw vacuum through the 4bbl, meaning possible better milage. It's also probably the best bang for the buck performance upgrade you can do. I think your engine will only draw in as much CFM as it needs anyway, regardless of the carb size, 500, or 600CFM.

 

[wca_tim]

Re: Has anyone upgraded to a 4bbl carb on their Mercruiser 4.3

600 cfm Edelbrock marine carb, model 1409, 89 jets front and rear, one or two metering rods richer than the ones that edelbrock recomends. vortec heads, cleaned up a bit, merc marine cam, edelbrock performer intake, port match the intake if you have the time and energy. Either way, no adapter needed. Add a free flowing air cleaner (the stock one sucks). We're talking 500 for brand new aluminum intake, carb, and jets, mine took about 34 degrees total timing and ran great. thumbs up.

have that v-6 on an engine stand on my carport right now.

OH, and it did very well on gas and would keep up with or even outrun many of the huys with v-8's in their (usually heavier) boats...

 

[sleeper]

Re: Has anyone upgraded to a 4bbl carb on their Mercruiser 4.3

It appears they make a calibration kit for the edelbrock 1409 carb when used with the 2111 (2114) aluminum intake manifold on a 4.3 V6. The eledbrock carb kit is 1485.

http://static.summitracing.com/global/images/instructions/edl-1485_inst.pdf


It looks like the 3 major parts needed are (one possible combination):

EDL-1409 Carburetor, Performer, Marine, 600 cfm, 4-Barrel, Electric Choke, Single Inlet, Gold Iridited, Each $335.95

EDL-1485 Carburetor Calibration Kit, Edelbrock Performer Series Carburetor, 1409, Kit $16.95

EDL-2111 Intake Manifold, Performer, Dual Plane, Aluminum, Natural, Square Bore Flange, Chevy, 4.3L, Each $199.95
(or for vortec heads - EDL-2114 Intake Manifold, Performer, Dual Plane, Aluminum, Natural, Square Bore Flange, Chevy, 4.3L, Each $244.95)

For a grand total of $552.85 ($597.85 with vortec) from summit racing.


I just wonder if the extra top end power will warrant a prop change to keep from hitting the rev limiter, which in turn will make the hole shot worse.
My boat came with a 23p prop. I have a 21p on it now, and its almost perfect. Good hole shot and 4800-4900rpm at WOT with light load. If I had more top end and had to put the 23p back on, hole shot might suffer.

I won't consider it until my warranty is over anyway.

 

[John_S]

Re: Has anyone upgraded to a 4bbl carb on their Mercruiser 4.3

sleeper,

That 4.3 Calibration kit is identical to Merc's Weber calibration on the 4.3L prior to vortec heads. If running vortec heads, you probably have to tweak it a little more.

 

[jkust]

Re: Has anyone upgraded to a 4bbl carb on their Mercruiser 4.3

I have to sound ignorant since I really am with carbuerators and engines for that matter. Does it make sense that their is no such thing as a highrise manifold for the 4.3? Also, any ideas of the CFM on the stock 2bbl carb?

 

[wca_tim]

Re: Has anyone upgraded to a 4bbl carb on their Mercruiser 4.3

sleeper,

That 4.3 Calibration kit is identical to Merc's Weber calibration on the 4.3L prior to vortec heads. If running vortec heads, you probably have to tweak it a little more.

I've set three of them up almost exactly the same as that, 2-3 metering rods richer than come with the "calibration kit", same springs and jets. Also, if you get a little off idle lean it's because the idle circuit isn't really big enough and rather than making the mid fatter, you can just turn the idle screws in an aextra half turn or so and it'll go away... or at least in my experience...

 

[wca_tim]

Re: Has anyone upgraded to a 4bbl carb on their Mercruiser 4.3

sleeper,

That 4.3 Calibration kit is identical to Merc's Weber calibration on the 4.3L prior to vortec heads. If running vortec heads, you probably have to tweak it a little more.

I've set three of them up almost exactly the same as that, 2-3 metering rods richer than come with the "calibration kit", same springs and jets. Also, if you get a little off idle lean it's because the idle circuit isn't really big enough and rather than making the mid fatter, you can just turn the idle screws in an aextra half turn or so and it'll go away... or at least in my experience...

don't worry about high rise, etc.... the parts above are the set-up that everyon's talking about and the best reasonably inexpensive upgrade... The performer manifold is just about right for that set-up...

 

[MikDee]

Re: Has anyone upgraded to a 4bbl carb on their Mercruiser 4.3

jkust, if it's a Vortec motor, here's a 4bbl manifold for you:
http://www.michiganmotorz.com/4.3L+four+barrel+Vortec+intake+manifold+(1996+-+2008)

 

[John_S]

Re: Has anyone upgraded to a 4bbl carb on their Mercruiser 4.3

wca: as I suspected, the vortec likes a little richer calib. Running the "standard" 4.3L kit could lead to a lean condition. Anyone considering the 4brl on a vortec 4.3L should start with your recomendation and then adjust from there.

 

[wca_tim]

Re: Has anyone upgraded to a 4bbl carb on their Mercruiser 4.3

my apologies... summit / edelbrock pn for vortec heads is 2114...