How Much Horsepower ?

[Tubingluvr]

I own a 1988 Sea Ray Seville Bow Rider with a 4.3 I/O (2 barrel carb)
I need to replace the carb and was thinking about switching it to a 4 barrel as long as I already have to replace carb.
I am looking at an after-market intake (Edelbrock Performer Rpm)
I believe I would be looking at at least a 30 hp increase.
I realize this would not do much for increased top end speed, but my question is whether or not this would allow for an increase in prop pitch.
I currently run a 14 3/4 X 21 which is a power prop for this particular boat.

 

[Bondo]

Re: How Much Horsepower ?

I currently run a 14 3/4 X 21 which is a power prop for this particular boat.

Ayuh,....... At what rpm,..??..??....

The swap you give you enough Difference to be able to Feel it in the seat of the pants........

 

[Tubingluvr]

Re: How Much Horsepower ?

Ayuh,....... At what rpm,..??..??....

The swap you give you enough Difference to be able to Feel it in the seat of the pants........

Sorry 4600 Rpm........... Spec is 4800 max

 

[Bondo]

Re: How Much Horsepower ?

You May, or may Not have to reprop.........

 

[a70eliminator]

Re: How Much Horsepower ?

2bbl to a 4bbl + edlbrock RPM = 30 HP your dreamin' no way. Maybe if you upgrade the cam ignition and exhaust, but simply bolting on those 2 peices by themselves will not do what your asking for, in fact your engine will probably just turn into a major gas hog.

 

[Tubingluvr]

Re: How Much Horsepower ?

2bbl to a 4bbl + edlbrock RPM = 30 HP your dreamin' no way. Maybe if you upgrade the cam ignition and exhaust, but simply bolting on those 2 peices by themselves will not do what your asking for, in fact your engine will probably just turn into a major gas hog.

My stock 2 barrel is rated at 175 hp..........a 4.3 with a stock Mercruiser intake and 4 barrel carb is rated at 205 hp ( that is 30 hp where I went to school)

 

[Bondo]

Re: How Much Horsepower ?

2bbl to a 4bbl + edlbrock RPM = 30 HP your dreamin' no way. Maybe if you upgrade the cam ignition and exhaust, but simply bolting on those 2 peices by themselves will not do what your asking for, in fact your engine will probably just turn into a major gas hog.

With the cast iron manifold,+ the Weber 4bbl,....... Merc rated Mine at 205hp......
The 2bbl. model of that vintage is rated at 180hp.......
Same Cam, Exhaust,+ Ignitions.....

And,.........
The Merc/Weber, Edlebrock Carter AFB Clones in the 600cfm Carb is a spreadbore design with Tiny primaries,+ Big 2ndaries.........

That Sea Ray stands to see a Fuel Economy Increase because of That alone.....
At lower cruising speeds of course........

 

[a70eliminator]

Re: How Much Horsepower ?

Sure the numbers add up, but compare the stock cam specs between the two motors as well as the combustion chamber volume, the pistons are probably different too flat top 4bbl vs your dished 2 bbl. I'm just trying to help you acheive the 30+ HP you want, you really need to research some of the specs of the 4bbl motor, just slapping a 4bbl carb and intake isn't going to net the HP.

 

[Bondo]

Re: How Much Horsepower ?

With the cast iron manifold,+ the Weber 4bbl,....... Merc rated Mine at 205hp......
The 2bbl. model of that vintage is rated at 180hp.......
Same Cam, Exhaust,+ Ignitions.....

Ayuh,...........

I'm telling ya,....... Part # for Part #...........Same Motor, Different Induction......
25/ 30hp.........

 

[a70eliminator]

Re: How Much Horsepower ?

Ok if you say so, I didn't realize it could be so easy to grab 30HP. If thats the case then hell yes gimme that 4 bbl.

 

[Tubingluvr]

Re: How Much Horsepower ?

I guess it would be a little easier if I explained my reasoning behind wanting to switch to a 4 barrell
When I bought the boat it had a 14 1/4 X 22 ss prop.
I switched to a 14 1/4 X 21 Aluminum for more out of the hole.
I run aluminum because our lake has such a shallow and gradual shoreline.
I would rather replace the prop than the lower end (have done that once already by the way)
I would like to go with a 14 1/4 X 23 but I need more hp to get the whole shot I want.........also the boat tends to be loaded down pretty good with people when it goes out..........one of the main reasons I own a bowrider

 

[whywhyzed]

Re: How Much Horsepower ?

Just did the 2BBL to 4 BBL conversion on my 3.8 using a stock cast iron Mercruiser manifold (3.8 intake same as 4.3 pre-vortec). I am quite happy with the performance gain.
As far as bang for the buck it has been great - cost me about $200 for used parts (used carb-75, new arrester-25, intake 100) and $50 for the carb kit and gaskets and such, and then, for rebuilding the carb I got a giftcard thing for my buddy to take his wife out for dinner.
I just chopped my 2BBL linkage bracket and mounted it to a diferent bolt on the intake- only modification I had to do.

 

[180shabah]

Re: How Much Horsepower ?

Before we get too far here, we need to examine the choice of intake manifold.

Performer RPM builds power 1500-6500
Performer builds power idle - 5500, probably a better choice so you don't give up any of your hole shot.

 

[MikDee]

Re: How Much Horsepower ?

I think a 25-30hp increase on the 4.3V6 by switching to a good 4bbl, & manifold is in the ballpark. Also shabah made a good suggestion.

 

[wca_tim]

Re: How Much Horsepower ?

I'm no expert, but can offer one data point. Current 18 1/2 foot boat, original 1988, 2bbl, 4.3, 1.84:1 gear ratio. previous owner said 47-48 mph gps with old (kinda beat up, came with) 23" laser II at wot. Didn't get rpm range, acquired boat / trailer in pieces.

currently: new reman (rapido) 4.3 with vortec heads, factory marine spec roller cam, electric fuel pump, edelbrock performer manifold and 1409 carb, factory exhaust manifolds, new lower unit (SEI, sheared lower drive shaft in original), hd ujoints and gimbal bearing, exhaust tube (could tell difference in backpressure when switched from original style bellows, sounds great when you hit the throttle too!), much newer / better condition laser 2 prop, lost (removed!) aftermarket "sabilizer fins" on lower unit. Finally got carb feeling right tonight with this change in metering rods, no hesitation or surging and a LOT more low to midrange power through wot than I expected.

the result: 57 MPH 5200 rpm trimmed out with pretty decent hole shot, planes out pretty quickly, great accelleration once on plane and cruising... just plain fun.

that's with full tank of gas (27 gal), two adults, large tool box (ca. 70-80 pounds; just in case), on 1 foot chop (not exactly a smooth ride...). Didn't hold it at full throttle for very long, may have been able to wring a bit more out of it. Still grinning ear to ear as I try to settle down and get things done for work tomrrow...

Hope this is adds a little more perspective to what you've already been given.

Cheers!

 

[wca_tim]

Re: How Much Horsepower ?

ps. I second above note on intake choice. I did a fair amount of looking at intake specs and talked with a couple of friends, folks at Edelbrock and a local shop. performer manifold apparently has much better torque profile than anything else readily available for a healthy marine spec 4.3. especially considering major importance of bottom end and mid range torque on seat of the pants assesment...

 

[Maj Easy 1]

Re: How Much Horsepower ?

here's what one guy did to increase his hp

ebay link

his auction runs out in 2 days,
here's the mods he listed:

? Recent Engine Upgrade
o Edelbrock 1409 Marine Carburetor
o Edelbrock 2111 Performer series manifold
o Edelbrock 1485 Calibration Kit
o Thermostat module
o Water pump housing / impeller
o K&N flame arrestor
o Petronix Flame Thrower ignition kit
 Ignition Coil
 Electronic Ignition
 Plug Leads
 Plugs
 Distributor Cap
 Rotor Arm
? Stainless Steel Skeg Guard
? Engine / Gimbal Bearing Alignment Tool

 

[whywhyzed]

Re: How Much Horsepower ?

here's what one guy did to increase his hp

ebay link

his auction runs out in 2 days,
here's the mods he listed:

? Recent Engine Upgrade
o Edelbrock 1409 Marine Carburetor
o Edelbrock 2111 Performer series manifold
o Edelbrock 1485 Calibration Kit
o Thermostat module
o Water pump housing / impeller
o K&N flame arrestor
o Petronix Flame Thrower ignition kit
 Ignition Coil
 Electronic Ignition
 Plug Leads
 Plugs
 Distributor Cap
 Rotor Arm
? Stainless Steel Skeg Guard
? Engine / Gimbal Bearing Alignment Tool

He forgot to mention:

Home Depot Garden Hose Breather Tubes !!

 

[180shabah]

Re: How Much Horsepower ?

Is it just me or does the current bid of$7600 seem a little high???

 

[Maj Easy 1]

Re: How Much Horsepower ?

Is it just me or does the current bid of$7600 seem a little high???

no, not just you....
unless i just got lucky because my 190 V8 with 250 hours cost only 6K....

nada value on my boat suggest i paid too much....