Tune up schedule for 2004 Mercruiser 4.3L 225hp 4bbl

[QBhoy]

Data sheet is here
https://samerwebapp01apncus01.azure...43l_alpha_4v_product_data_sheet_8m0080486.pdf

225 hp with 4 bbl carb

Ok. Had a look there. It’s a remanufacture engine. Not a newer previous engine brand new. Basically an overhauled engine.

 

[Lou C]

Way back when Merc was still using the pre-vortec V6 they sold them with Quadrajets, and probably did sell them with the Weber copy of the old Carter 4bbl.

 

[QBhoy]

Way back when Merc was still using the pre-vortec V6 they sold them with Quadrajets, and probably did sell them with the Weber copy of the old Carter 4bbl.

They sure did. I had a couple. But they weren’t 225 hp in their most powerful 4 barrel form, they were 205hp standard. More usually 190hp and about 175 in 2 barrel form.

 

[achris]

They sure did. I had a couple. But they weren’t 225 hp in their most powerful 4 barrel form, they were 205hp standard. More usually 190hp and about 175 in 2 barrel form.

225hp is with Vortec heads, and a 4 bbl carb (probably a Weber). Yes, they aren't 'new' engines, they come from Merc's re-manufacturing section, but they are still 4.3L, 225hp....

Don't quote me on this, but I suspect that 225hp is at the crank. The 4.3MPI is 220hp at the PROP.... So 225 at the crank and a 4bbl and vortec heads is on par with a 205hp at the crank with non-vortec heads....

Chris.........

 

[QBhoy]

225hp is with Vortec heads, and a 4 bbl carb (probably a Weber). Yes, they aren't 'new' engines, they come from Merc's re-manufacturing section, but they are still 4.3L, 225hp....

Don't quote me on this, but I suspect that 225hp is at the crank. The 4.3MPI is 220hp at the PROP.... So 225 at the crank and a 4bbl and vortec heads is on par with a 205hp at the crank with non-vortec heads....

Chris.........

You’ll be right, I’m sure chris.
My point, at the risk of trying to save face haha, is that the chap who posted the question originally, has a 2004 engine. That wouldn’t have been 225hp with a 4 barrel carb in those days surely ?

 

[achris]

You’ll be right, I’m sure Chris.
My point, at the risk of trying to save face haha, is that the chap who posted the question originally, has a 2004 engine. That wouldn’t have been 225hp with a 4 barrel carb in those days surely ?

Vortec heads on V6's started in the mid-1996, so a 2004 engine with vortec heads is entirely feasible.

History of major changes to the V6 (262) used by Merc.

1985 to 1992. First generation. Non balance shaft, fluid mounts. 2 variants, 2 bbl carb producing 175hp, 4 bbl carb producing 205hp. Thunderbolt IV ignition. Cam-driven mechanical fuel pump. 'Tin' timing cover.

1993 to 1996. Known as 'Gen II'. Balance shaft. Electric fuel pump, 'Solid' mounts. 'Tin' sump. Same 2 carbed variants.

1996 to current. Known as 'Gen +'. Composite timing cover. Cast ali sump. Vortec heads. Serpentine belt. Variants include 2bbl and 4bbl carb (with Thunderbolt V ignition), EFI and MPI.

Hope that clears things up.

Chris.......

 

[Scott Danforth]

Chris, agree with the generalizations , however the variations are more granular than that at the base engine level.

1985 is a 2-piece RMS crank - one year only
1986-1987 is 1-piece RMS crank, center bolt valve covers and a few other changes
1988-91 is start of roller cams
1992-95 balance shaft (major block change), change in mounts, and commonization of flywheels with the 5.0 and 5.7
1996 is the start of vortec heads, plastic timing cover and cast pan
block was re-designed in 2000, 2003 and again in 2007

 

[QBhoy]

Just simply saying....
There was no 225hp carb in 2004. That’s all.

 

[QBhoy]

There is still no 225hp carb put in a new boat now, even. You would need to buy a remanufactured one.

 

[achris]

There is still no 225hp carb put in a new boat now, even. You would need to buy a remanufactured one.

Can't see any reason not to put a remand engine into a new boat.

 

[QBhoy]

Maybe customer satisfaction, haha. I wouldn’t be happy.