1999 5.0l alpha 220hp convert to 4bbl carb???

[jy118lfd]

I have a 1999 seamaster walkaround, I really like the boat and was wondering what improvements I would see with going to the mercruiser 4bbl manifold and a q jet carb. Would I lose some mpg? How much power gain could I see?

I am not looking for top speed just a little more low end for rough water and getting out of the hole. Right now it runs 35 to 37 mph at wot 4800 rpm and cruises at 25 to 27 mph at 3500 rpm With a 15X16 michigan 4 blade alumnium prop. It gets 2.0 to 2.3 mpg at cruise on the flowscan depending on the load.

Boat weighs approx 5,000 lbs fully loaded with fuel and gear

 

[jy118lfd]

Re: 1999 5.0l alpha 220hp convert to 4bbl carb???

Forgot to mention, Boat is a 2388 24' in length with 20 degree deadrise

 

[Bondo]

Re: 1999 5.0l alpha 220hp convert to 4bbl carb???

Going from a 2bbl. to a 4bbl. Carb will Usually net you about 30hp........

I prefer the Merc./ Weber/ Edlebrock/ Carter Clones to the Rottenchesters Myself......

These are the Carbs that Merc. has gone to, since the Q-Jets are No longer used......

Whether your GPH goes Up, or Down will have a Direct Relationship to Your Control over Your Righthand........

The 600/ 650cfm Carter Clones have Small primaries,+ Much Larger 2ndaries, kinda like the Q-jets,....
So,... With the Smaller Carter Clone Carbs,... You Might get Better GPH,.......
If you stay Out of the 2ndaries........

I Gota Think that you'll see a Major Improvement in the general Power available to you.......

 

[180shabah]

Re: 1999 5.0l alpha 220hp convert to 4bbl carb???

Is your engine RWC or FWC?

If you are fresh water cooled, skip the merc manifold and get a good Aluminum one. The edelbrock performer is a good one, especially if you pair it with their carb.

 

[f_inscreenname]

Re: 1999 5.0l alpha 220hp convert to 4bbl carb???

I have used aluminum intakes for years on salt water boats. Just make sure where the intake blocks off the water ports at is covered in RTV.
The water passages must be coated in something. Either that or the iron from the block covers it like a protective paint. None I have used (Edelbrock) ever show any corrosion.The passages just end up with a orange/red stain after years of use.

 

[jy118lfd]

Re: 1999 5.0l alpha 220hp convert to 4bbl carb???

Its raw water cooled and I was thinking of using a carb like this one

http://cgi.ebay.com/ebaymotors/MARI...015QQitemZ250085692886QQrdZ1QQsspagenameZWDVW

 

[f_inscreenname]

Re: 1999 5.0l alpha 220hp convert to 4bbl carb???

Not a big fan of the QUADRAJET. I prefer Edelbrock to all else but its what you are more comfortable with.

 

[180shabah]

Re: 1999 5.0l alpha 220hp convert to 4bbl carb???

Ditto the edelbrock, they are simple and reliable.