520 fuel injection

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airboater67
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520 fuel injection

Post by airboater67 »

IO-520 doesn’t run well at idle. (Sometimes) new facet fuel pump has pressure and injection pump makes pressure on its own when pump is off. Runs great on the gas just an idle and cold start problem. Hard to get it to stay running on cold start. This engine is straight out of a plane and sometimes it idles really nice. Just a little hesitation right off idle. I know nothing about this engine . Still learning. Is there something obvious that I should check? Both mags working rpm drops when I kill each one. . Haven’t checked timing or points as I said sometimes it runs perfect, so I had no reason to think it was off. Seems like a fuel issue . Any help appreciated. Haven’t checked unmetered fuel pressure but metered is 2 1/2 to 3 at idle. What should these pressures be?

BobBrack
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Re: 520 fuel injection

Post by BobBrack »

If my memory serves me correctly you want right around 10 psi at idle and 25ish at full throttle. Im sure there are several articles with the correct numbers on line. Just do a search. I do know that 3 psi is to low.

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airboater67
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Re: 520 fuel injection

Post by airboater67 »

So it seems I have an injection pump issue

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Slidin Gator
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Re: 520 fuel injection

Post by Slidin Gator »

Look at the overhaul manual, you can find a copy posted here:

https://www.southernairboat.com/pdf/air ... ental/520/

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I still think I-10 is the Mason Dixon line.
2013 Mike Stossel Boats, 13' x 7' deck over, IO-540, 74" NGQ less winglets.

mwood7800
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Re: 520 fuel injection

Post by mwood7800 »

Do yourself a favor and put a carb on it

woodlineO540
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Re: 520 fuel injection

Post by woodlineO540 »

I have been converting 520s to airflow performance fuel Injection it runs off of constant pressure I run a High pressure EFI fuel pump (walbro) to a fuel pressure regulator and set the pressure at 25 psi and the regulator has a return line back to the tank
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Slidin Gator
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Re: 520 fuel injection

Post by Slidin Gator »

woodlineO540 wrote:
Mon Nov 23, 2020 6:21 pm
I have been converting 520s to airflow performance fuel Injection
What are the pro’s and con’s?

I run Continental injection on my angle valve Lycoming. Starting is a learned skill but performance has been instant and reliable.
I still think I-10 is the Mason Dixon line.
2013 Mike Stossel Boats, 13' x 7' deck over, IO-540, 74" NGQ less winglets.

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