Upgrade 2b carb to 4b on 4.3L for hole shot power

[jrampey]

Re: Upgrade 2b carb to 4b on 4.3L for hole shot power

OK, I've been watching this thread... I have a 2007 Mercruiser 4.3l with the 2bbl mercury carb. Its advertised at 190 HP. What can I do for more power? 4 bbl carb? new intake? I've got that "Tim the toolman - MORE POWER" ailment.

 

[df909]

Re: Upgrade 2b carb to 4b on 4.3L for hole shot power

I'll be getting my prop this week & I'll put an update on here. I tried using a hydrofoil and already took it off. The boat may have planed a bit faster, but it really changed the way the boat handled- a change for the worse. So, I recommend against a hydrofoil in case you were thinking of it.

 

[180shabah]

Re: Upgrade 2b carb to 4b on 4.3L for hole shot power

jrampy, you really need to start you own thread, as hijacking is frowned upon.

You have a few options for increased performance, but we can discuss them in the new thread.

 

[180shabah]

Re: Upgrade 2b carb to 4b on 4.3L for hole shot power

I'll be getting my prop this week

What did you decide on?

 

[ricovw]

Re: Upgrade 2b carb to 4b on 4.3L for hole shot power

just to give you an idea of what props can do....I was running a 3 blade 19P aluminum prop, and wanted a better holeshot for skiing. I bought a 5 blade, 19P stainless prop (called highfive), and it made all the difference in the world. Lost a bit on the top end, but i don't run it there cause i ski and tube. I throw the aluminum prop when going for cruises..

 

[df909]

Re: Upgrade 2b carb to 4b on 4.3L for hole shot power

I decided to go with the aluminum 4 blade 19 pitch. I'll have the stainless 3 blade 21p repaired and keep it as my spare. I don't really care about top end as I want to pull the kids on a tube & ski and use it for fishing. I'm not going for speed as that's when a lot of dangers seem to sneek up on people.

I don't think I'll be changing it depending whether I'm ocean fishing or playing in the lake. I'll post an update here with the performance with the new prop.

I'll leave the carb alone for now also.

 

[King P.V.]

Re: Upgrade 2b carb to 4b on 4.3L for hole shot power

Perhaps this comment is too late, maybe not!!!! Most "bang for the buck" is (for skiing and holeshot) the stainless 5 blade High Five prop. I don't know of any shops that will remove your intake manifold and carb, replace with 4 barrel stuff AND not change the prop out, thereby giving you the "power" you so desire anyway!!! Don't waste your money on any prop other than a high 5.... And don't waste your $$$ on any other "fix" either!! I've sold more high 5's to more people who wanted more hole shot ......they LOVE 'em!!!!! I give them a money back option if they don't like 'em , they always do!! Always!!

 

[df909]

Re: Upgrade 2b carb to 4b on 4.3L for hole shot power

What's the price on something like that? I've seen stainless props that are way more than what I'm willing to spend.

 

[mkast]

Re: Upgrade 2b carb to 4b on 4.3L for hole shot power

Try a shifting propeller.
Land and Sea or the Quicksilver Power 2.

 

[skier-24]

Re: Upgrade 2b carb to 4b on 4.3L for hole shot power

Good luck finding a Torque Shift. Land and Sea hasn't made props for five years due to a fire in their factory. I can't find information on the Quicksilver so I expect they are extinct too.

 

[JimKaz]

Re: Upgrade 2b carb to 4b on 4.3L for hole shot power

The Qucksilver Power 2 is no longer made, but here's one on ebay.

http://cgi.ebay.com/ebaymotors/Merc...6243668QQptZBoatQ5fPartsQ5fAccessoriesQ5fGear

 

[sickwilly]

Re: Upgrade 2b carb to 4b on 4.3L for hole shot power

Right here on Iboats you can pick up a solas 4 blade aluminum prop for $100 bucks. You may still do the intake carb thing some day because lets face it, us boaters lover to tinker, but in the meantime you will have your whole shot!

I second the hi 5, I have one. But for the bucks its hard to beat good ole Iboats and the 4 blade solas prop! That is my spare!

 

[df909]

Re: Upgrade 2b carb to 4b on 4.3L for hole shot power

So what's a 5 blade run? I tried looking them up but only found 20p & above. I should have my new 4 blade 15 Dec and will be on the water no later than the 16.

 

[mylesm260]

Re: Upgrade 2b carb to 4b on 4.3L for hole shot power

More CFM through the carb will give you more PEAK power, but do NOTHING for bottom end.


Using a lower pitched prop will work, but sacrifices cruising RPMS.

The real question is do you have trim tabs?
If you don't, the very first thing you should do is install some smart tab SX's. I installed them on my boat and it made a WORLD of difference in plane time, min plane speed, and ability to handle rough water. The decrease in plane time was like going down 4 prop p's (I know because I have a 23 and a 19P prop, and I run my 23 95% of the time)

Mind you, every haul is different, but for my boat (Regal medallion 195 W/ EFI 230 HP 4.3). it made a HUGE improvement.


I'm 260 lbs, and I can get up on my wake-board with 8 ppl in my boat running my 23P prop. Before the smart tabs, I would need my 19P prop to do the same thing.

 

[Bondo]

Re: Upgrade 2b carb to 4b on 4.3L for hole shot power

So what's a 5 blade run?

Ayuh,... About $500./ $600....

More CFM through the carb will give you more PEAK power, but do NOTHING for bottom end.

Not to argue Myles, I respect your opinions,+ knowledge....
But,...
With the Tiny primaries of the AFB style 600cfm carbs,...
The increase in Velocity does definitely make a Difference in low-end...
And,...
I Completely Agree that a set of tabs could make the most difference per $ spent...

 

[df909]

Re: Upgrade 2b carb to 4b on 4.3L for hole shot power

Wow, that's a big difference. I don't have trim tabs but, like everything lese, I've thought about it. I'd like to take the boat out with my boys to do a little ocean fishing and we'd have a bait tank or bag. Trim tabs would help with all the stern weight.

Are they fairly easy to install? As far as I know, there would be hydraulics, power to the unit, and a gauge and switch at the console. Anyone know of a handy dandy guide to installing trim tabs for people that think they're mechanically inclined?

 

[Bronc Rider]

Re: Upgrade 2b carb to 4b on 4.3L for hole shot power

You probably just need smart tabs. These are self adjusting and cheaper. The adjustable ones are considerably more expensive and maybe even overkill on a smaller hull. They sell them here at iboats. The 4 blade Solas prop is a very good inexpensive prop. I hear good things about the Hustler prop but I have never used it. They are similar in price.
In my experience a 4bbl carb will improve both top and bottom end. You do see most of the difference above mid rpm's but, it will also be apparent everywhere else in the rpm range.

 

[Bondo]

Re: Upgrade 2b carb to 4b on 4.3L for hole shot power

I don't have trim tabs but, like everything lese, I've thought about it.

Ayuh,... Search "Smart Tabs" in the Boating forum+ the restoration forum...

 

[Bronc Rider]

Re: Upgrade 2b carb to 4b on 4.3L for hole shot power

Here is a link to smart tabs in the iboats store: http://www.iboats.com/Nauticus_SX_Smart_Tabs/dm/*******.506161477--**********.387380139--view_id.352485

 

[mylesm260]

Re: Upgrade 2b carb to 4b on 4.3L for hole shot power

Ayuh,... About $500./ $600....


Not to argue Myles, I respect your opinions,+ knowledge....
But,...
With the Tiny primaries of the AFB style 600cfm carbs,...
The increase in Velocity does definitely make a Difference in low-end...
And,...
I Completely Agree that a set of tabs could make the most difference per $ spent...

Okay, I am certainly going to yield to you're opinion, given you're experience. You obviously know 1000 times more than me when it comes to marine motors. Especially since the only boat I've ever owned had a carb on it for all of about 2 hours of use, then I yanked out the motor and swapped it out for a 4.3 vortec EFI.



In Automotive land though, usually the CFM limits of a carb don't become an issue until a given RPM.

for example, a 2bbl and a 4bbl could have the same torque curve up to 3500 RPMS, and then the 2bbl will start to drop torque, where the 4 bbl will not, which results in more HP.

and just to echo again, smart tab SX's made a HUGE difference on my boat.