Fuel system upgrades

Engines, Shafts, Steering, Struts, Rudders, etc.
Tranquilo
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Fuel system upgrades

Postby Tranquilo » Thu Sep 03, 2015 9:49 am

I replaced my ignition system and it runs great. An issue that I'm recently finding is that it seems that my fuel system can't keep up with the higher rpms. When getting to 3200, she keeps cruising for a short while then "burps" frequently enough to make me take it down to 2900 or so so she runs smoothly.

I noticed that my inline glass fuel filter seems to indicate that fuel stream is getting thin around that range.

I also noticed that since discovering the burps that my starting is really hard. I'm having to shoot starting fluid in the carb half the time to start it cold.

Could this be a failing fuel pump? My 318 should have a mechanical pump, which I would think would run forever.

Thoughts?
2x 1973 28 Express - Single 318
New electrical panels, water system and velvet drive
Miami FL & Catawba OH

jmonday
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Re: Fuel system upgrades

Postby jmonday » Thu Sep 03, 2015 11:44 am

What carb do you have?
Jeff Monday (Blue Mondays)
1973 28 ft Express single 318 1976 StarCraft Islander 1961 Sea Nymph
Lower River rd
Rabbit Hash KY

jralbert
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Re: Fuel system upgrades

Postby jralbert » Thu Sep 03, 2015 2:26 pm

check/replace the little filter where the fuel line enters the carb
-joel-
former owner 1988 '32 FB Sedan
Chesapeake Bay
twin 318 / 240 hp
Potomac MD

Tranquilo
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Re: Fuel system upgrades

Postby Tranquilo » Thu Sep 03, 2015 3:14 pm

I just replaced both filters before the carb (there is a large fuel separator right after the tank)

I have an Edelbrock carb:

https://www.dropbox.com/s/sgevhjsgznmv7 ... 1.jpg?dl=0
2x 1973 28 Express - Single 318
New electrical panels, water system and velvet drive
Miami FL & Catawba OH

jmonday
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Re: Fuel system upgrades

Postby jmonday » Thu Sep 03, 2015 3:20 pm

Same here. Did you time it on a light? Most of my problem was the firing but i did change my manual pump to an electric.Much easier to change and cheaper now. If you have a gage check the fuel pressure they need to be above 3 and under 6. high fuel pressure is bad on the 1409's.
Jeff Monday (Blue Mondays)
1973 28 ft Express single 318 1976 StarCraft Islander 1961 Sea Nymph
Lower River rd
Rabbit Hash KY

jralbert
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Re: Fuel system upgrades

Postby jralbert » Thu Sep 03, 2015 4:25 pm

I had the quadrajet with that filter at its fuel inlet point. And it caused the same problems you noted when it got clogged. I attached a marked up shot of yours with the question of whether the Edelbrock has the same filter.

Carb.JPG
-joel-
former owner 1988 '32 FB Sedan
Chesapeake Bay
twin 318 / 240 hp
Potomac MD

Tranquilo
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Re: Fuel system upgrades

Postby Tranquilo » Thu Sep 03, 2015 8:35 pm

Interesting... I didn't know there would be a filter so small. I'll look that up.

I tested it today with the 2 fresh fuel filters I knew about (you may have shown me a third I didn't know about) and here is the common symptom:

I can throttle up from 1500 to 32-3500 no problem as long as its fast. Once at 32-3500, it roars for about 20 seconds before sputtering, taking me into 2500 rpm purgatory. I can wait awhile and bump it again to 3k for a few seconds before it sputters again.

I'll look into the timing thing because I'm curious but wouldn't that be more consistent and not a problem that just started one day and after running at higher rpm for 20 seconds?

The fuel pump pressure is the question that seems logical to me as well as the "mystery filter" in the carb. I guess I should be careful with the replacement pump because some of the hollys push 15 psi.

I looked at the electric conversions but didn't see any that seemed practical for boating. Any pump suggestions?

I want to source some things before the weekend if possible. Otherwise, we'll be stuck cruising the bay or anything within 5 miles of Key Biscayne. While fine (first world problems), I had hoped for a longer trip since I got gas for $2.45 a gallon today.
2x 1973 28 Express - Single 318
New electrical panels, water system and velvet drive
Miami FL & Catawba OH

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Busia
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Re: Fuel system upgrades

Postby Busia » Fri Sep 04, 2015 12:45 am

You're running out of fuel. That is what it will do when that little filter gets dirty. Pull it out and blow it out in the reverse direction and you will be able to go fast. Napa or any auto parts store will have them in stock.
BUSIA
located in Ketchikan, Alaska. Gods country
32 foot Marinette express. (no fly bridge)
twin 350 Crusader (Chev 350) engines
1:1 Borg Warner velvet drive transmissions
Closed cooling (antifreeze in the engine)
Proud to be retired IBEW

Fastjeff
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Re: Fuel system upgrades

Postby Fastjeff » Fri Sep 04, 2015 5:37 am

Sounds like fuel pressure problems alright. I suspect your mechanical pump has gone bad. They are very reliable, but nothing lasts forever; and let's not forget the effect of ethanol in the gas: it eats up some types of rubber (as in pump diaphragms).

I know it's not easy to do, but if you T'eed in a 0 o 15 psi fuel pressure gage, you would know instantly if pressure is your problem. The carb should see about 5 to 7 psi all the time--no more, and no less.

Jeff

PS: Don't keep pushing it or you may burn a piston!
"We live at the bottom of an ocean of air, not at the top." General Marvage Slatington

jmonday
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Re: Fuel system upgrades

Postby jmonday » Fri Sep 04, 2015 6:22 am

Eldelbrock 1409 carb does not have a filter on the fuel line inlet. Airtex is the electric fuel pump I went with it is rated for marine use E8337 check with the tech guys to see what would work best with your tank and line length setup.
Jeff Monday (Blue Mondays)
1973 28 ft Express single 318 1976 StarCraft Islander 1961 Sea Nymph
Lower River rd
Rabbit Hash KY