4.3 Hp ratings ???

[joewithaboat]

Im hoping some of you mercruiser mechanics/experts can help me. I have looked around and found conflicting information..

I have a 1996 Caravelle. 4.3LX, alpha 1 genII, 4 brl
engine # 0f765276
drive # of702962

engine appears to be 100% original
I have seen horse power ratings of 175,190,205
I am of course thinking of changing out parts to upgrade to the higher 230hp version with Vortec heads. I am finding it hard to believe that heads, and a serp belt system would take it from 190hp (which is what i think i have) to 230hp. I can't really find any other major differnces that would affect hp rating ????
In looking for cam info it looks like they all use part #803186 which replaced for some reason # 824327

Thanks in advance !

 

[Struc]

Re: 4.3 Hp ratings ???

The 175hp/185hp ones are 2bbl carbed motors. Not sure on 190hp. Pretty sure the 4bbl was 205hp, and yeah, the vortec head models were 230hp.

 

[Bondo]

Re: 4.3 Hp ratings ???

Ayuh,... The difference between the 190hp, 'n the 205hp is the year whichever number was stated by Merc...

The Vortec heads are good for an honest 20hp/ 25hp....

 

[joewithaboat]

Re: 4.3 Hp ratings ???

Ayuh,... The difference between the 190hp, 'n the 205hp is the year whichever number was stated by Merc...

The Vortec heads are good for an honest 20hp/ 25hp....

I found something else that mentioned a roller tip rocker on later vortec heads? Know anthing about that?
Again Thanks!

 

[joewithaboat]

Re: 4.3 Hp ratings ???

Ayuh,... The difference between the 190hp, 'n the 205hp is the year whichever number was stated by Merc...

??? Are you poking fun at merc and saying that there is no difference?

 

[Bondo]

Re: 4.3 Hp ratings ???

Ayuh,... The difference between the 190hp, 'n the 205hp is the year whichever number was stated by Merc...

??? Are you poking fun at merc and saying that there is no difference?

Ayuh,... I'm sayin' they've used Crankshaft hp, 'n Propshaft hp, dependin' on the Year...

 

[joewithaboat]

Re: 4.3 Hp ratings ???

Ayuh,... I'm sayin' they've used Crankshaft hp, 'n Propshaft hp, dependin' on the Year...

That explains alot... thanks!
I had wondered about that and quickly wrote it off because info i found said they made that change in the late 80's, guess they changed again?

 

[Don S]

Re: 4.3 Hp ratings ???

Your serial number is model number 443L100JS which is the 4.3LX which is a Gen+ engine.
In the manual it shows that the 4.3LX had a 2bbl carb and was 190 hp. The 4.3LXH had the 205 hp rating.
Problem is, they don't show any hp rating for the 4.3LX with a 4bbl carb, only the 2bbl.
The model number you have, also doesn't show up under the LXH, and the LXH only used a Bravo drive.
My guess is, you still have the 190 since that is taken at max WOT rating for the engine, and just never changed in the manual.
The parts manual for your engine shows both 2 and 4bbl carbs for the LX.

 

[joewithaboat]

Re: 4.3 Hp ratings ???

Your serial number is model number 443L100JS which is the 4.3LX which is a Gen+ engine.
In the manual it shows that the 4.3LX had a 2bbl carb and was 190 hp. The 4.3LXH had the 205 hp rating.
Problem is, they don't show any hp rating for the 4.3LX with a 4bbl carb, only the 2bbl.
The model number you have, also doesn't show up under the LXH, and the LXH only used a Bravo drive.
My guess is, you still have the 190 since that is taken at max WOT rating for the engine, and just never changed in the manual.
The parts manual for your engine shows both 2 and 4bbl carbs for the LX.

Thanks Don,
I was running into the same contradictions looking at the mercruiser info. It had me going back to look at the boat to see if i could find any signs intake and carb having been changed. It all looks original.

I was just trying to figure out if bolting on the Vortec heads (and proper intake) was worth it.
Seems it might be.

 

[achris]

Re: 4.3 Hp ratings ???

Your serial number is model number 443L100JS which is the 4.3LX which is a Gen+ engine....

Interesting... My listing shows that model (using the serial number) as a Gen II, not a Gen +. I had that engine previously in my boat and it is rated as 180 propshaft horsepower... The Gen + was released about 2 weeks later (Gen + started with Serial 0F803000) and was available as LX (190 hp with a 2 barrel carby) or LXH (205hp with 4 bbl carby) or EFI (210 with throttle body injection)....

 

[achris]

Re: 4.3 Hp ratings ???

Addendum....

I currently have the 2006 MPI (Vortec heads, roller cam, leaky timing cover) rated at 220 propshaft hp and I picked up only about 3 or 4 knots in top speed. What I did gain of significance is fuel mileage. Was using about 1.7 litres per nautical mile (at cruising speed), now about 1.3 litres per nautical mile.... I also got rid of the crappy Weber carby (Carter AFB copy really)....

Chris........

 

[Fun Times]

Re: 4.3 Hp ratings ???

Im hoping some of you mercruiser mechanics/experts can help me. I have looked around and found conflicting information..

I have a 1996 Caravelle. 4.3LX, alpha 1 genII, 4 brl
engine # 0f765276
drive # of702962

engine appears to be 100% original
I have seen horse power ratings of 175,190,205
I am of course thinking of changing out parts to upgrade to the higher 230hp version with Vortec heads. I am finding it hard to believe that heads, and a serp belt system would take it from 190hp (which is what i think i have) to 230hp.
Thanks in advance !

Since you have the 4 brl, your engine H.P at the prop is 175, Had you have a 2 brl your engine model would have been a 4.3l and the power would have been 155 H.P at the prop according to sevice manual # 18 on page 1B-7 (< See link below). Or if you go by the owners manual it shows the 4.3 LX model to be 180 H.P, & the 4.3L to be 160 H.P.

Pretty sure they did not make a 4.3 LX model with a 2 brl back then.
4brl's on the NON GEN+ engines where 4.3 LX and the 2 brl's were considered a 4.3L if I remember correctly.

http://www.boatfix.com/merc/Servmanl/18/18B1R2.PDF

Interesting... My listing shows that model (using the serial number) as a Gen II, not a Gen +. I had that engine previously in my boat and it is rated as 180 propshaft horsepower... The Gen + was released about 2 weeks later (Gen + started with Serial 0F803000) and was available as LX (190 hp with a 2 barrel carby) or LXH (205hp with 4 bbl carby) or EFI (210 with throttle body injection)....

Agreed, I show this engine to be a GEN II as well. I'm sure Don Meant to say GEN 2 and not GEN +.

Joe, Your engine was manufactured back on 9/1/95, But your engine is considered to be a 1996 MERCRUISER TB5, W/PS, TWOPCEX, WORO 4.3LX ALPHA Model No: 443L100JS (Gen II) when looking up parts.

Merc's parts catalog part number 90-801874 96 - Covers both the 4.3L & LX Alpha/Bravo (Gen II) engines.

 

[joewithaboat]

Re: 4.3 Hp ratings ???

Thank you to all five of you that replied......

In the merc #18 it seems to group the specs of the 4.3l and 4.3 lx together... then the gen+ engines. It gives limited specs but it appears the comp is .10 different and different spark plugs, not sure if that means heads are a little different or maybe pistons, or just head gasket. Some of the factory paper work i got with the boat even showed two differnt hp numbers.:facepalm:

I started looking, thinking that for a little trouble, I could get and rehab a set of vortec heads and buy an alm intake and have 230hp. I just dont want to tear into it to find that vortecs alone wont get me close. I cant find anything that confirms different cams in any of these. I only found the two part numbers i had listed in the o/p. Never came across anything with piston part numbers. If any of you dig up anything let me know and thanks again.

 

[achris]

Re: 4.3 Hp ratings ???

Spade in hand.

 

[achris]

Re: 4.3 Hp ratings ???

4.3LX (Gen II) part numbers.
Pistons: 735-850097 (standard size)
Camshaft: 431-824327
Head gasket: 27-816460

4.3LX (Gen +) part numbers.
Pistons: 735-835001 (standard size)
Camshaft: 431-824327
Head gasket: 27-816460

Head gaskets and camshafts are the same, heads and pistons are different...

Hope this helps....

Chris..........

 

[joewithaboat]

Re: 4.3 Hp ratings ???

Chris,
Thanks, I used those numbers to try and cross check to find more info on the actual piston. Couldnt find much other than they both also fit the 350ci. offerings from mercruiser. Both appear to be cast. The odd thing is the one in the higher hp motors cost less. Go figure...

The cam seems to be the same all the way up to the 262 mag motor, which also uses that same piston from the Gen+. Rocker arms appear to be very different in 1999. Dont know if that is a GM or mercruiser thing, roller trunion. ever have your valve cover off ?

Anyway i think i will take a look at swiching to the vortec heads and a edelbrock intake. Hopefully it doesnt end up being a valve size/valve relief issue. Afterall Mercruiser used different parts for a reason i guess. Thanks for your help.

p.s. Most of your fuel savings from fuel injection you figure?
My boat uses suprisingly little fuel, the least of any i/o ive ever operated. Thats why ive resisted thowing a 350 in it.

 

[Bates7985]

Looking for Information on my 4.3. Just purchased a 94 Monterey 190 SCR with a 4.3 LX ( SN 0F148067) with 330 hrs. After speaking to Mercruiser the engine was manufactured in 93. But it has Vortec head Covers, an 8 bolt intake manifold and a ribbed aluminum oil pan. Didn’t the 93s have the 12 bolt intake manifold? I could be wrong. Ultimately I’m trying to figure out if this is a mismatched SN or if it’s an actual Vortec motor. How do you tell the difference. This boat at WOT did 53 mph on the water. Which seems extremely fast for a regular 4.3. Any insight on this would be greatly appreciated. Thanks.

 

[jbcurt00]

Looking for Information on my 4.3. Just purchased a 94 Monterey 190 SCR with a 4.3 LX ( SN 0F148067) with 330 hrs. After speaking to Mercruiser the engine was manufactured in 93. But it has Vortec head Covers, an 8 bolt intake manifold and a ribbed aluminum oil pan. Didn’t the 93s have the 12 bolt intake manifold? I could be wrong. Ultimately I’m trying to figure out if this is a mismatched SN or if it’s an actual Vortec motor. How do you tell the difference. This boat at WOT did 53 mph on the water. Which seems extremely fast for a regular 4.3. Any insight on this would be greatly appreciated. Thanks.

Start a topic about your 4.3 Mercruiser and ask again there

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