Re: [OMC-Boats] Fuel pump for '67 Surfer from BC Howk on 2009-12-14 (OMC-Boats Mailing List Archive)

From: BC Howk <bchowk@...>
Date: Mon, 14 Dec 2009 11:18:26 -0600 (CST)

John,

Thanks for the tip on the fuel pump..........

I use a spacer with my Holley 4BBL, I installed it to solve some "fitment" issues with the conversion but I think it does help in my application with some extra volume and making my dual plane intake behave like a single plane........My 2 cents for your application, I don't think it could hurt anything :-)

Fuel injection would be very interesting and would LOVE to hear from anyone who has seen it done on a boat and hear how it turned out.....couple things that spring to my mind....

1. Placement of the O2 sensor, maybe it is not a big deal BUT I wonder since there is water being pumped through the exhaust manifolds, will the sensor work properly, or if you put it way forward will it give a skewed reading to the computer based on the health of the 1 or 2 cylinder?

2. Marine application is a little different than cars when it comes to tuning....cars shift and start then stop, with boats we tend to idle around for long periods or throw the throttle down and stay at high RPM for some time.......Point being that a the way cars adjust their timing or set up their fuel table might not be ideal for your boat, so I would think adjustability would be a fairly important...anyone have experience with this?

Cheers,

B.C.

Dec 13, 2009 05:16:33 PM, omc-boats@... wrote:

Recently, my re-built carb choked on too much fuel when running full-tilt and I was not hitting Spec RPMs of 4K - 4.4K; maxxed out at 3.8K Since I didn't want to go back to a mechanical pump, I embarked on a journey to find an electric fuel pump that met or came very close to specs and the closest I could find was the NOS / Up to 200 HP 5/16 in. inlet/outlet 18 GPH at 4 PSI 12 Volts small displacement fuel pump from Autozone.com. It's only 3 GPH higher than the spec of 4 PSI/15 GPH specs for my Buick v-8 300 ci engine. Interestingly, it's a marketed as a high performance motorcycle category product. Installed it last weekend and I am now getting up to the Spec RPMs. Thought I'd share as looking to a High performance Motorcycle categorized fuel pump (albeit turns out to be a re-labeled Polish manufactured auto pump) was not an expected path to a solution.

Some Questions for the group

Has anyone used a Spacer with their Rochester 2bbl? Is it a common practice?

I am looking to a) reduce heat to carb and b) create more distance between throttle body/cable connecting area and manifold as I've had to double up some gasket material to keep from scraping the manifold when moving the throttle. Makes me wonder if a Phenolic Carb Spacer was standard....more likely my cable connection is non-spec.

What are folks opinions re: the use of "Performance spacers" like the one found at the following page: http://marine-performance-parts.com/search.aspx?find=PS109-P ? It claims, "
huge airflow and power gains for those using a Rochester 2 barrel carburetor on Chevy / Mercruiser 2 barrel intake manifolds. " Ex. bad idea in Marine applications because of X...or great for increasing low end torque....etc

What about the use of Throttle Body Injection such as the following? http://www.affordable-fuel-injection.com/store.php?crn=209&rn=436&action=show_detail This is a stock GM ECM with a static mapping, so I wouldnt be able to tweak it, but the supplier claims they will be able to calibrate it to the specs of my engine.

Thoughts/comments desired and welcome as I could use some help as I think through my next step regarding whether to go with a standard spacer, performance spacer, or TBI (most expensive option by far and feels like it may be overkill).

Best,

John

'67 Surfer

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Received on Monday, 14 December 2009