Merc 5.0L Carburated performance?

[Regency19]

Hey all, I have a 91 Dynasty Regency with a Mercruiser 5 liter with a 2bbl carb. I would like to have more performance out of the boat, but not exactly sure what to go with first. I am planning on changing the prop too. Currently it has a 19 pitch prop on it and only hitting 4000 rpms when full throttle. I plan on going with a 17 pitch prop to get the boat in the rpm range it needs to be and help it get out of the hole better. The mods I was thinking of are:

high performance intake manifold (which one?)
4bbl Carb (edelbrock? )
Ignition upgrades?

Let me know what you guys think. Thanks
S

 

[Bondo]

Re: Merc 5.0L Carburated performance?

A 350 with that Edlebrock will swing that 19,.......... Maybe a 21..........

The 4bbl. will Wake Up that 5.0l,......

Forget about the Ign. System,......... The T-Bolt is about the Best Thing Going...........

 

[Regency19]

Re: Merc 5.0L Carburated performance?

ok, so I did some hunting around. I was thinking about getting an Edelbrock performer Manifold #2104 and an Edelbrock Performer carb #1404 500cfm or the #1406 600cfm carb. Has anyone tried a similar combo?

I wish I could get a 350 in this thing!! That would rock. But all I got to work with is this 305 for now

Thanks for the help.

 

[John_S]

Re: Merc 5.0L Carburated performance?

The carbs you listed are auto. You need a marine carb. Try 1409, it is 600cfm and has vac door on secondarys. They will only open for what your engine needs.

Your rpms seem low, but I don't know what kind/size/weight of boat. Guessing a 19'er from your screen name. Do you know your drive ratio? Just want to make sure there isn't other problems before upgrading.

 

[Regency19]

Re: Merc 5.0L Carburated performance?

ok, I saw the 1409 too, but wasn't sure it would make a lot of difference. I'll look into that one for sure. Yeah it's 19' Boat. It tops out pretty good, but acceleration sucks for sure. When I hit it from a stop, it takes forever to plane and when pulling a skiier, it just drags them alot. I was told the prop pitch could help the boat achieve more rpm's and get out of the hole quicker. The prop pitch now is 19, I was going to look for a 17 pitch prop and see what it does. Performance used to be better if I remember correctly, but the boat has always had problems getting out of the hole quickly. Thanks for all the help!!!

 

[cjames]

Re: Merc 5.0L Carburated performance?

my stock 5.0L, 4V(Qjet), 228hp merc tops out at 4200rpm, which is right at spec by the book. I normally cruise at 3200 rpm. Any more than that, its into the secondarys, and with the price of fuel these days, I dont like to hear those secondarys open. It may be a good idea to check out the specs on your engine, and see what the rated RPM is before you try and start getting more out of it.

 

[180shabah]

Re: Merc 5.0L Carburated performance?

ok, I saw the 1409 too, but wasn't sure it would make a lot of difference. I'll look into that one for sure.

It will make a HUGE difference. The auto carbs will make your boat go BOOM.

 

[Tail_Gunner]

Re: Merc 5.0L Carburated performance?

http://www.edelbrock.com/automotive/carb_square.html#marine

600 cfm, Electric Choke

Designed and calibrated for optimum marine performance in small-block V8 engines with a variety of manifolds that include Edelbrock Performer, Performer RPM, RPM Air-Gap, Torker II and other brands of similar design. Also ideal for Chevy 4.3L V6 engines with a Performer manifold (page 50) and Calibration Kit #1485. Comes with: Metering Jets ? Primary .098, Secondary .101; Metering Rods ? .068 x .047; Step-Up Spring ? orange (5"

If you call Edelbrock i am sure they will also recomend a new metering kit.

 

[Bry21317]

Re: Merc 5.0L Carburated performance?

Can anyone tell me what the difference would be going form a 2 barrel Rochester on a 5.0 up to a 4 barrel Edelbrock 1409 as stated in this post? And also the Edelbrock Performer Intake.

I am just toying with the idea, of getting some more power. Just wondering what it might do for me.

Figured I would keep it in this thread, if I get no replies then I will try my own thread. Didn't want to hijack it, but since it was pretty much the same question.

My boat is a 1994 Crownline 196BR with the Chevy 5.0 with thru hull exhaust. It gets up and runs pretty good, she will go in the 50s without thinking twice.

Bryan

 

[tommays]

Re: Merc 5.0L Carburated performance?

I would say there is a motor problem if you can only hit 4000 RPM

be it a bad tack or what ever


It should have no problem spinning a 19' prop well past 4800 RPM



Tommays

 

[Bry21317]

Re: Merc 5.0L Carburated performance?

Sorry My motor screams.

I am turning a aluminum 21 Pitch Prop up to 5200 rpms and am going to a 22 or 23, not sure yet.

My boat comes out of the water fast with this prop, and my boat is heavy, it weighs 2800lbs by NADA boat guides. Its a 19 ' 6" with an 8'6" beam.

Just wondering what the going to a 4 barrell might do.

Bryan

 

[tommays]

Re: Merc 5.0L Carburated performance?

Bry

You need to start your OWN thread we cant help REG19 with his problem trying to help you decide about a 4 barrel carb



Tommays

 

[180shabah]

Re: Merc 5.0L Carburated performance?

Ditto

 

[Bry21317]

Re: Merc 5.0L Carburated performance?

Sorry about that guys.

So Reg19, did you ever get the boat running right?

Bryan

 

[180shabah]

Re: Merc 5.0L Carburated performance?

I would say there is a motor problem if you can only hit 4000 RPM

be it a bad tack or what ever


It should have no problem spinning a 19' prop well past 4800 RPM



Tommays

I agree, my 4.3LX kisses 5k spinning a 21" Hustler

 

[Bry21317]

Re: Merc 5.0L Carburated performance?

How do you like that 21 pitch hustler, 180Shabah?

I just put one on my boat, have not yet tried it. Just put it on tonight, hope to try it out this weekend.

Not trying to hijack the thread.

Bryan

 

[180shabah]

Re: Merc 5.0L Carburated performance?

How do you like that 21 pitch hustler ?

No complaints, it is definately better than the original merc prop.

 

[bdbunch]

Re: Merc 5.0L Carburated performance?

consider tourtque shift prop?

I have one and out of the hole on a low like 14 to 17 and high end on 19 to 21 is really nice.