Question about carb vs. EFI for course skiing

[Kevin89MC]

Long time lurker here, but I don't post much.

My main question: is there much of a difference in how they feel to a slalom skier?

Quick background and reason for the question: On a good day I get deep into 28 off or a few at 32 off. Been at 34 mph but spending more time at 32 mph recently. So not a shortline skier by any means, but always trying to improve. Currently I have a 1989 Prostar, 351 w/ GT40 heads, 1:1 trans, classic PP with slalom switch. A very good ski boat, but looking to upgrade for more space. I ski a lot behind a friend's 1996 Nautique 176, same engine and reduction trans, classic PP w/switch. My absolute favorite boat to ski behind, but even smaller than mine. My wife's cousin has a 1999 Response LX, no speed control, just free ski. I have a friend with a 2000 Response LX with classic PP that I get in the course once a year. Great boats to ski behind as well.

I'm mainly looking at 1999+ Response LX (also considering PS 197's). They RLX has got everything I need and nothing I don't and are starting to become affordable. I found a good deal on one on onlyinboards, at Tommy's of Detroit, and they have another one there as well. The odd thing is one of them has EFI and the other one has a carb. I was pretty sure Malibu had gone EFI by then in the Responses, but maybe not. I believe the Echelons may have had carbs, but this one is a Response, as it has a trunk (decals were replaced). I don't mind having a carb from a maintenance standpoint, but I wonder if the EFI would be better from a course skiing perspective, as far as engine/throttle response. No matter what boat I get I will be getting PP SG, and maybe Zbox as I struggle a bit when skiing tournaments as that is the only time I see Zero Off. I plan to post this on themalibucrew.com to see what they think as well. My guess is PP classic would be fine with carbs, but thinking SG is maybe better suited to EFI?

Appreciate any thoughts.

Thanks,

Kevin

[BraceMaker]

It's not so much difference EFI vs carbs. It's that new boats are about 200 more horsepower. I've used PP stargazer in carbed 91 and LT1 EFI boats. If you have Z-box in both the efi will pull harder but you can turn it down

[BraceMaker]

Carbs respond pretty well due to the Accelerator pump.

[6balls]

Get the EFI, it's just nice. I'd have a hard time going back to carb. Sure it will do, but why when there's EFI. Do love the sound of a carb V8 on start up after prime and some RPM's!

[DW]

The bigger difference is ones with the '96 and newer Vortec cylinder heads that bumped HP from 285 to 310. Significant improvement in airflow.

Note - PP does have a comment in the manual on correcting any surging if by chance you are running at the point where the secondaries kick in. Never was an issue for my PP controlled carbed boat.

[2Valve]

EFI does just about everything better. Starting, smoothness, idle, emissions, throttle response and of course, good 'ol horsepower.

[DW]

@2Valve - careful when you claim EFI is better for HP, many a dyno run will disprove that claim. People underestimate the benefits of fuel air mixing farther back up the intake tract and the venturi effect on atomization of the fuel. Not saying carbs are better, as you note many aspects EFI is the clear winner, just pointing out that a carb is not quite the black sheep some think it is. Actually my carbed engine idles better than both EFI boats on our lake and at a silky smooth 600 RPM to boot, cold starts it is the clear loser.

[GregHind]

Vacuum secondaries are a problem when they kick in. Most boats operate below that range for slalom skiing but they are a pain if they do kick in as they make a big difference with tiny throttle movement.

For barefoot they can mean 3mph speed change.

For me, EFI please.

[Jody_Seal]

@DW

I agree. We went through a couple beautiful years right up in front of efi where those that knew how to set the carbs up with perfect pass had a pretty sweet ride.

 

Earlier this year I repowered a 2000 Malibu reponse. The customer could not invest into efi and zo so I installed a new long block vortec engine and kept the carb set up. Boat was pretty sweet in the slalom course with pp and a z-box. Aparantly it is a 33.6 jump beast also..

 

[Kevin89MC]

Thanks everyone for the comments so far. After more research it looks like the carbed engine was standard into early 2000's and the Monsoon (& others) were optional engines. All the ones I've seen have the Monsoon so I assumed it was standard. Agreed it might be a HP issue more than a carb vs. EFI issue. When my '89 351 engine was stock, it was a bit of a dog compared to the other boats I skied behind (carbed and early EFI). I could slow it down in the course, and then it would speed up at the ball to regain time, so it always felt "fast" to me. It was not fun to course ski behind. I upgraded to GT40 heads (HP went from ~240 to maybe ~270 or more) and it was immediately a much better boat to ski behind. So I won't rule out the carb, as they can be easier to get more HP out of, but the EFI would be nice for the reasons listed by others. HP with the carb is listed at 310 and HP with the EFI is 325, so not a huge jump. Good to know that others have had good success with PP SG on carbed boats. I agree about the secondaries, they don't kick in when I ski at 34 mph, but they do when I pull 36 mph skiers. No complaints, but I think the guy I ski with is too nice to say anything!

[Orlando76]

Piss on EFI. Go carb. Unless you want endless troubleshooting down the road and terrible customer service along with the harsh pull you get with ZO, opt for the Holley 4160 and PP.

[Jetsetr]

4160’s are vacuum secondaries...the engine loading is what opens them, and only as much as needed. You’re not at wide open throttle @ 36, not even close. I’m not sure you’re going to feel them “kick in”....but I would think it would be gentler than EFI and ZO depending how hard you load the rope...

 

I could be wrong, wouldn’t be the first time today!

[BraceMaker]

@Jetsetr - you really don't want to feel the secondaries on a Holley. I can tune a secondary so you feel it but all you're doing is making it so there is a power lag on the primaries before the secondaries start to contribute.

 

Holley carbs are more clever than people give them credit for with all the transfer passageways, vacuum secondaries, acceleration pumps, power valves etc there really is something that is supposed to be happening at all points in time to provide good smooth responsive power.

 

Running PP with a switch or PP with Z-Box you have tuning options for how you want the boat to feel and there are a few "cheats" you can do such as drilling shortening the pivot point on the carb arm if you wanted more juice (more angular change on the arm per motion of the PP cable). Setting KX + or ++ will give you more response. There is a Zbx value with Z-box which also increases response. There is ABC adjust. With a switch you have PX settings for the engine response when the switch closes.

 

 

[2Valve]

@DW Good points. My PCM block is a throttle body system with the injector's on top of the Rochester throttle body. I really like this setup and appears to offer the benefits you outline in terms of complete atomization. And yes, cold starts are seamless, even with 900+ hrs.

[eleeski]

My MC 197s with fuel injection were magic over my carbed boats. First one with PP Classic and second one with ZO. Maybe I gained buoys, I certainly didn't lose buoys with each upgrade (coming from a carbed bubble butt Nautique - regarded as one of the easiest slalom boats ever).

 

The magic came in reduced fuel burn. Noticeable reduction despite a bigger boat. Even more significant at trick speeds. Add the reliability of the Indmar fuel injection and the cleaner exhaust and there's no question which is better.

 

Note that PP had problems interfacing with early drive by wire systems. ZO fixed that. My 2004 197 had a regular throttle cable and PP Classic worked perfectly for me. The UCSD 2005 MC 197 had DBW and was horrible with PP. The engine from the 2010 Nautique 200 that I put in the American Skier had the electronic throttle on the engine so it would have adapted fine to PP.

 

I've never liked Stargazer (and the couple Zbox rides haven't impressed me) so I'd recommend ZO which definitely requires fuel injection.

 

The new technology is superior. But costs more. Fuel injection and ZO, worth it!

 

Eric

[BraceMaker]

@eleeski - we really have no choice right now. My fear with ZO is that it is entirely at the whim of E-controls supporting the towboat industry. If too few boats sell to justify the three event system being supported POOF bye bye speed controls.

[wilecoyote]

I'll just throw this in. How important is dependability? As stated above the 4160 is a good carb, and I for one don't really care about the cold start issue as it's summer and 3 pumps on the throttle to prime and a little goose when it fires works every time. As soon as you go to any type of EFI it's more sensors, computers, pumps and wiring. My boat(Supra rider PP classic) is only for free skiing, which is at a cottage with no spare parts for miles. I don't want my boat dead for half my vacation while I'm waiting for parts. At home, I ski the course (very poorly) behind brand new Mastercrafts. I'm considering upgrading, and at my level, I'm much more concerned about the wake than the motor. 22off behind my boat the wake is brutal so I can't even compare the pull until that gets sorted.

[eleeski]

@BraceMaker You do have a legitimate concern. However if ZO abandons the ski market, PP will be able to reenter the new boat market and (after some griping) we will adapt to PP's standard.

 

ZO appears to be improving their relationship with the skiers. I got excellent response and customer service recently with my Rev S upgrade. Hopefully your concerns are unfounded.

 

Note, I plan to someday convert the old 2004 MC to an electric motor. PP is the only current option for that. I definitely like the idea of having choices.

 

Eric

[dvskier]

How many of you carburetor lovers have a daily driver vehicle that has a carb? Not many made in the past 10 years. I get the desire to fix it yourself but I’ve had Nautiques since 1997 with fuel injection and can tell you that it’s been a pleasure not having to have carbs rebuilt every 4-5 years. Reliable and great fuel economy/performance.

[BraceMaker]

@dvskier Daily driver type cars were 100% EFI in the US by what 1990? Boats lag tech qise by a huge margin. But a 94 EFI boat is very similar to ~1990 EFI Chevy Truck. Conversion to carb quite easy. What happens when a 2019 EFI boat with all its functions in a touch screen is 30 years old? Do we think SN will be selling you new screens?

[dvskier]

No touch screen for me. I have a 2004 SN, will keep it until it dies. I’m not a fan of Linc, never have been. When the existing boat dies it will be replaced with a gently used promo. Some enterprising millennials will probably have aftermarket parts for all inboards by then.

[ReallyGottaSki]

If the gizmos go dead and the zombies come out, an LS aluminum square flange intake and standalone spark box is what, 700 bucks?

We'll always be able to ski these things somehow

[wilecoyote]

@dvskier The new tech does not make new cars any more dependable than they used to be (with the exception of electronic ignition which I do have on my boat). It makes them more fuel efficient and dummy proof. Neither of which I value in a boat over being able to ski when I want to. Also something to consider in the reliability case, having your car not start when you are out is an inconvenience, having your boat not start when you're out and the weather is rolling in can be literally fatal. Not all of these boats are on ski lakes that you could swim to shore with a tow rope in your teeth and pull it in.

[JackQ]

I was a mechanic many years ago and continue to preform maintenance and repair on a number of vehicles and boat.

 

I firmly believe EFI performs better, is more efficient and is more reliable that carbs were/are. However, often when issues arise diagnostic are more difficult. However, this is for TBI and port injection, time will tell if direct injection will have increased reliability issues. They certainly are more costly and much more challenging to diagnose and have already shown to have carbon deposit issue in many vehicles.

[BraceMaker]

@ReallyGottaSki plus rewiring for a key, gauges, perfect pass. Having to someone reconfigure the dash to mount said things.

 

I'm not talking zombie apocalypse. 90s ski boats were 24 grand and are now 10. If your 100K boat craps out...

[dvskier]

@wilecoyote Back in the 80s I had carb’d boats, always getting gunked up. Required carb rebuilds, etc. Pumping throttle for cold starts. Now I turn the key and ready to ski. Primarily I ski about a 1/4 of a mile from my dock. When I had a battery go bad I swam the boat back home. No worries for me about getting stuck on the lake.

 

[swc5150]

I'm just sitting on the davenport, enjoying some Werther's Original and listening to the ball game on the radio, while reading posts about the benefits of carburetors. Seriously, this a conversation occurring less than 2 months from the year 2020? :)

[jepski]

The EFI/zo boats I've skied behind are pretty amazing, and out of my budget.......for both purchase and maintenance. As a shade tree mechanic, skiing with an older 285hp Indmar MC with mechanical PP...the simplicity of a carbed engine - combined with PP is a sweet, low maintenance, low cost solution to enjoyable skiing. My current no-start diagnosis is fuel, spark, or air. My fear is the 2014 Prostar I can afford in couple years,I try to fire up but have a no-start and dead screen...leading to time consuming diagnostics, dealer involvement and costly parts.

[Orlando76]

Opener at 28. Run a few 32’s back to back, run 2-35’s, run 5@38, make the next 38, work on a few gates at -39. Two pumps of the throttle for a cold start?? Pfffft, that’s just too much work.

 

And what’s this rebuild carburetor talk? Don’t waste your time. $650 for a new carb and you’re golden for 5+ years. That’s $110 a year. The maintenance kit for a direct injection pcm is what, $600 a year?

[dvskier]

@Orlando76 Since 1997 when I acquired my first SN I’ve invested about $7 per year for a can of Sea Foam. When I had a carb’d boat it was not as cheap to maintain. Pretty sure I wouldn’t know how to replace a carb. If it works for you that’s great.

I don’t open or ever get to 28 off.

[BraceMaker]

Carbs are 4 nuts 2 gaskets a fuel line a hose a linkage and a wire to the choke...

[jepski]

@BraceMaker - it took me longer to unbox my new 4160 than to install it.

[BraceMaker]

Yup.

[dvskier]

Don’t they require many adjustments, re-jet, etc?

[Orlando76]

@dvskier re jetting is sometimes needed in certain performance scenarios but definitely needed in higher elevations. Even I would go EFI if I were skiing sea level in the morning then the Colorado Rockies at lunch time.

[ALPJr]

Carb worked ok here

 

[eleeski]

This is crazy. I'd get a couple years out of a new boat before it needed a new carb. Then yearly carb replacement was normal. I used my boats a lot back then but not excessive hours. I had to work on and spend $s on them a lot.

 

My fuel injected engines have NEVER needed any fuel injection system maintenance. The 04 MC had problems with the in tank fuel pump which were permanently solved by a new MC pump. The college kids ruined the engine when a hard freeze hit Bako without winterizing the boat. Lots of hours and abuse of that boat with very little maintenance.

 

The 11 MC had a sensor fail a few years ago (wouldn't start to back out of the boathouse). The gas gauge never worked well so I just replaced that. Pretty low maintenance for the last 9 years.

 

Whether it's the fuel injection or just improving technology, new boat engines are far more reliable than old ones.

 

Eric

[Jetsetr]

If a boat needs a new carb every year I would say its operator error more than the carb...

If you can’t figure out what is wrong with something as simple as a 4160 maybe one should stick to riding skate boards...or find a better mechanic. One that actually knows something rather than just throwing a new carb on every year...this ain’t rocket science...

 

Fuel injection IS BETTER than a carb (except 1st gen GM TBI) I will not argue that.

However, probably more than 1/2 the DD ski boats still have a Holley residing under the engine cover.

They work good, they’re simple and they last a long time...

 

 

[ReallyGottaSki]

I can add the only time I've had to open my carb in 24 years was when the mechanical pump shredded it's gaskets on it's one-way valves

 

I think the typical cartridge filter system on carbed boats did everyone a disservice and is responsible for much of the chronic headaches, as well as lack of any filtration between pump and carb

 

Long ago I threw out the cartridge cannister and put in a mercruiser style spin-on filter system, I feel it's responsible for the better results.

 

If carbed boats had smarter filtration that rivaled the FI boats, I suspect the fustration levels would not have gotten so out of hand for so many

 

 

 

[MDB1056]

Carbs are so simple,and yes even to rebuild or replace. And what - is a couple of pumps on a cold start too much work? As a 63 yr old still cranking and having fun at -32@34 and not competing I’m more than happy with the simplicity of my 90’s carbd 350 Chevy. About as easy to work on as the 68 big block in the garage. You guys can have all the high tech high cost boats. I’m incredibly content, and stress free!

[Jetsetr]

@MDB1056 agree 1000%!

I’m 56 and have been working on all types of engines since I was 14. I rebuilt my first SBC at 16.

I can REPAIR a carb...Broke/no start FI would leave me standing there with a dumb® look on my face...wouldn’t know where to begin. And that would piss me off because I wouldn’t be able to use my boat...

I have probably just bought my last ski boat, and it has a carb...

[BraceMaker]

My opinions re the new boats would be very different if the computers were obd2 plug and GM compatible....

[BrennanKMN]

I prefer electronic controls and standard communication protocols on all my engines/vehicles. I find them much easier to troubleshoot. I simply plug my laptop in and I can watch 100's of sensors and data points in real time, graph them, log them during issues, ect. That is a very powerful diagnostic tool to me - especially when issues go beyond just the engine.

 

That doesn't mean I want electronic everything. I still think screens and proprietary communications are going to kill us one day. One of the reasons I am a huge CAN bus fan is because I can openly read and interact with it in anyway I want.

 

For everyone that says they like using a carb because it is an easy fix when something goes wrong, that is like saying you prefer solid tires on your car to eliminate flats. That is only ONE of the many many possible things to go wrong. I wouldn't run out and replace my carbureted boat with EFI, but if you are in the new market and are only looking at carbureted boats because of that 'feature' you are shorting yourself.

[paul]

I drive a carb’d boat and another that is fuel injected. Running a carbed boat for me isn’t a big deal although I still prefer fuel injection. Better fuel economy and less fumes. However with my wife and kids driving, fuel injection is the only way to go. To get them pumping the gas, running the boat at high idle, starting it after it has sat for a couple of hours is a pain in the ass. Fuel injection is turn the key and go...

[MDB1056]

@BrennanKMN - those 100 sensors are each something to potentially fail. This isn’t about a lobby to say one is better than the other, rather just a reality check on the complexity factor. Modern injection systems are of course more complex. Both will pull skiers at whatever speed is needed. Most boat owners quite frankly aren’t capable of working on a carb or FI system anyway . For many of us simpler is just fine. Personally in 28 years I’ve rebuilt my carb one time ( 3 years ago) and it was simple. I’m content. 2 pumps to cold start isn’t too much effort.

[BrennanKMN]

I agree, I don't think there is a right and wrong per-say. I just prefer one over the other for the reasons I listed. I'll take my data with the downsides of potential sensor failure.

 

I have 8 extra gauges in my truck over what the factory dashboard provides. I have identified several issues before they were a true problem because of them. I like data, I understand how things are operating and can better notice a deviation from normal.

[DW]

In addition to Holley's being simple, the Weber carb on Mercs is also easy to play with. Its a darn good thing FI is potentially more efficient since the new hulls all require a lot more Hp to drag them through the water.

[Jody_Seal]

Working for CC in the early 90's we intentionally stayed away from fuel injection as the other company's were utilizing it. We just did not feel it was worth the effort or increased potential for fail.

As we progressed PCM came out with projection fuel injection. It was a mishmash of sourced out components that really was not so good, temperamental and showed early fail. I changed a lot of factory boats back over to carburation because of it.

Then we go the GT-40 . After it came standard with the FCC the product was truly a dream come true for marine fuel injected engines. The GT40 package was a open loop style efi. Only a handful of sensors and great performance to boot. Truly a simple efi setup.

Then along comes big changes in the automotive world and the gt package gone. Until we had to go catalytic the engines remained pretty simple as far as electronics. Now a days though we have true marvels of electronic engine management.

I really dont mis the carby days even though it was simplicity at its core. But I also dont mis float sticking and flooding my engine, vapor lock on a hot day, secondary's crashing in at 4 ball, pump it twice before you start for the first time.

The power plants may have gotten more elaborate in today's world but at least one can turn the key or push the button start and away we go. I really dont see many sensor fails but what i see is when they do many so called techs / mechanics really dont know how to fix them.

 

[MDB1056]

@BrennanKMN if you have 8 MORE gauges in your truck than factory you're a significant distracted driver risk IMHO . data is great - but not while moving .........

[BraceMaker]

@MDB1056 - Not a real issue, most of the time when you're driving you don't actively monitor gauges, you already actively have all sorts of things you're not checking. I'd bet his extra gauges are simply things that the factory supplied only a light instead of a gauge such as transmission temperature and battery voltage.