I've run several brands of electric and mechanical (Carter, Mallory, Edelbrock) on cars and boats over the years. I've seen failures in both. My mechanicals never stranded me on the lake although I blaimed them wrongly a time or two. My electrics never stranded me either although they certainly tried a time or two.
Bottom line: For a boat, I'd pick mechanical here's why...
With electric you really should have an oil pressure cutoff for several reasons. Superdave013 mentioned one...the stuck float valve. BTW, his post makes sense for lake boaters too. But there's other reasons. Thing is, adding that safety cutoff means one more part in your fuel system that can fail.
With electric you need to mount the pump low if you want it to work right. Right down there where fuel vapors are traped and collect, unlike a car. That's why you really should run a marine electric pump, expensive if even offered in your choice of brand?
That said, electric pumps with good parts and setup will run safe and reliable. But from my experience with both, mechanical is the best overall. Mech doesn't need marine protection or sensors. Consider price:
Edelbrock Victor Mechanical (350-1712): $83
Magnaflow Regulator (MRF-MP-9633): $150
Total: $233
Mallory Comp Electrical Marine (650-4140M): $250
Regulator included (lists for $83): N/C
Oil pressure cutoff (SUM-G1438): $12
Total: $262
Even with a pricey Magnaflow regulator, the mech system's still cheaper. You have less parts...no electrics, no extra wiring or connections, sensors or safety measures, yet delivers the fuel. Fuel enough for big power.
So what's the mechanical downside?
Priming as Chris (flat broke) mentioned. If you let your jet sit a long time (as in weeks, not days or hours) with mechanical you're gonna crank awhile before carbs are ready to go. Hand priming bowls through the vents...not a good idea IMO. Don't know if there's a safe way to manually prime bowls, but by vent can be bad. Get an air lock and you're filling intake, maybe a cylinder or two not to mention throttle plate pin leak out the carb on top the engine. Could get messy...vapors in the bildge. Static electricity or cranking with plugs out to clear the cylinders of fuel and a non-marine starter? Fire.
But priming or fuel spills won't be an issue w/mechanical off-season if you do one thing: Start your engine every other weekend or so, let it idle a bit, then shut her down.
Keeps lines primed and carb bowls filled. Keeps seals lubed and fuel deposits from clogging carb aerteries. Helps keep oil up where it should be. In other words, start her up regularly off-season and fuel priming with a mechanical pump is no longer an issue, and you may see other engine benefits.
jer
I prefer a mechanical pump but couldn't find a good high volume pump for my BB Olds so I designed a six valve NASCAR style pump. Then I noticed the same lack of a good mechanical pump for several less popular engines so I started RobbMc Performance Products. We have 110 and 220 GPH mechanical pumps for many of the "forgotten" V8's:
http://www.robbmcperformance.com/products.html
I have a Century boat I've been working on, it has both a mechanical fuel pump and an electrical fuel pump. They are parallel'd with a check valve to bypass the electric pump. This was a factory option for Century boats, and made for quick primeing a boat that had sat for a while. It saved the owner a tow once, nice back-up deal.
Sleek
I have a Century boat with both a mechanical fuel pump and an electrical fuel pump. They are parallel'd with a check valve to bypass the electric pump. This was a factory option for Century boats, and made for quick primeing a boat that had sat for a while. It saved the owner a tow once, nice back-up deal.
Sleek
Interesting a manufacturer offered that option. Combining the two makes for a fast prime and a backup, but also may double the cost. In some cases the complexity and potential for failure. Here's what I ran a couple seasons...
http://members.cox.net/lvjetboy/FuelDiagram.jpg
http://members.cox.net/lvjetboy/DualFuel.jpg
Two independent electric fuel systems. I tried this design because I had an electric pump give out on me. I thought, why not a backup? That and I wanted two independent yet balanced flows from either sadle tank. It worked, but more connections and two electric pumps so more potential leaks and headaches. Thing is, one reliable high performance mechanical pump w/a regulator can do the same thing. That while supplying enough fuel flow for big power.
jer
Simple, Small, and puts out some flow..
http://www.racepumps.com/tech.html
Probably a great idea BUT $300 plus shipping, no thank you. BL
mechanical
Funny Jer, my boat shares the exact same fuel system schematic, as your PC does. I will be getting new braided hoses, and AN fittings, this season, time to call Sweet Performance Products again
Sleek
http://www.hotboatpics.com/pics/data...63100_0338.JPG
Funny Jer, my boat shares the exact same fuel system schematic, as your PC does. I will be getting new braided hoses, and AN fittings, this season, time to call Sweet Performance Products again
Sleek
http://www.hotboatpics.com/pics/data...63100_0338.JPG
Fuel pressure regs should be located much closer to carbs. Budlight
Fuel pressure regs should be located much closer to carbs. Budlight
They are about 24 inches away, from the single 1050 carb. Too far away? I have no fuel feed or pressure related problems. Can you add some more insight on this.
Sleek
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