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Inboard Flightcraft performance and starting issues


CentralOhioFlighty

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Hi folks, just wanted to say I've been stalking the site, while waiting on my membership approval. You all are certainly a helpful tool in answering some of my questions. I do have a few remaining questions though...

I have a 94 Flightcraft that I purchased in GA a few years ago and am very pleased with its capabilities. I will be getting the boat out from storage soon and want to try to tackle a "hard start" issue. I find that on the initial start up, when launching the boat, it wants to crank forever and with out a small shot of starting fluid, it wouldn't start. I generally try to give it a few choke pumps prior to cranking, and have tried holding choke wide open, but still wont fire. Once the boat is up and running, it will start all day long, no problem. I have been thinking about pulling the factory Weber carb and having it rebuilt, but I'm unsure if I'm having a carb problem or if my choke is just malfunctioning? Can anyone relate?

We primarily use the boat for long line footing and the occasional slalom run. I'm pleased with the power range, but just like all guys, I want more!! I'm realistic in knowing that I wont pick up too many more mph, but am looking for more low-mid range torque/power. I have searched the site for threads on the Edelbrock Performer(seems pretty popular) and carb upgrades. From what I've read, my Weber should be sufficient if properly tuned, do you agree? Is there anything else I need consider when ordering the performer, or is it a simple "bolt on" item? I found in another thread that Vortec heads are recommended, as well as exhaust manifold upgrades. Do you guys recommend a specific prop for long line footing? I will have to look at what prop is currently on the boat, but I seem to get a top speed of 44mph with two people on board.  I'm trying to keep my wish list under $2k, just want some feed back if I'm on the right path or not?  Thanks for looking!

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The choke - do you mean you are holding it closed or holding it wide open?  It should be closed completely for a cold start.  I would start with making sure the choke is working right, if it runs great once warmed up.  Sounds like a simple choke adjustment and your carb is likely fine.

As far as sufficient, yes, my engine with the stock Weber carb puts out 385hp (stroker crank, .60 over pistons, cam, vortec heads, Performer intake, roller rockers, etc.).  With all those engine mods that carb still delivers everything that the engine needs.  I could get another 10hp out of it with a larger carb, but that's about it. 

Others will probably chime in regarding good mods for your engine, I know a lot about my specific build but that's about it.

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@COF:  Assuming your engine is probably a standard Mercruiser Tournament Ski boat engine, the current intake manifold is comparable to the Edelbrock Performer RPM, other than material, they are exactly the same, so a swap to a Performer will not gain you anything.  It sounds like the choke is simply not working, do you have an electric or mechanical version?  On the electric there is an adjustment to increase or decrease the choke closing tension.  I would suggest a carb rebuild to be a good idea, it is very simple to do and might clear up any other running stumbles or hesitations you might have.  As for getting some more grunt, certainly very possible and the best place to start is to upgrade the cylinder heads to the "newer" (post 1996) Vortec style head.  You can find several varieties or basic flavors from GM units to aftermarket copies (from Summitt, Jegs or other suppliers).  That alone will bump your hp rating from 265 to 310 hp and is a very good upgrade that helps throughout the rpm range.  After the heads, the next limiter tends to be the exhaust side, and there are various higher/improved flow manifolds on the market.  The base manifold simply dumps in to a central chamber that does not promote good airflow, so units with a more defined exhaust runner can help.  Diameter can also be an issue, and there are exhaust system components available in larger diameter or you can simply make some yourself, not a very difficult DIY project.  There are also several camshaft options available although the GM marine cam is actually very good and given your comment, probably not a necessary change, but you could go with 1.6 ratio rocker arms to get a little extra in the airflow department.  A ZZ4 cam will actually wake up the upper midrange and higher end quite a bit if you want another excellent cam option.  As for prop, that will actually depend on what you do with the engine upgrade and may take some fine tuning to get the ideal combination.  Assuming you have a standard offering from that era, you most likely either have a cast nibral or stainless CVP unit.  A newer style CNC version from Acme or OJ will improve performance and given footing is the primary objective, I would stick with a 3 blade.

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