Fuel issue Marine Power 5.7

[AS19-1]

2001 Marine Power 5.7 vortec (315HP) Holley 4160. When the vacuum secondaries open around 3600 rpm I noticed I had very very little fuel coming from the secondary side nozzles. Carb was just rebuilt and I rebuilt secondary side again just to be sure and same issue. Boat is new to me and before I used it for the first time I replaced the fuel pump. The fuel pump I bought is rated at 4-5.75 psi. Could this be my problem? Did I buy a pump with not enough pressure? Any other ideas? What fuel pressure is required for my motor specs? Thanks

 

[Bondo]

Re: Fuel issue Marine Power 5.7

2001 Marine Power 5.7 vortec (315HP) Holley 4160. When the vacuum secondaries open around 3600 rpm I noticed I had very very little fuel coming from the secondary side nozzles. Carb was just rebuilt and I rebuilt secondary side again just to be sure and same issue. Boat is new to me and before I used it for the first time I replaced the fuel pump. The fuel pump I bought is rated at 4-5.75 psi. Could this be my problem? Did I buy a pump with not enough pressure? Any other ideas? What fuel pressure is required for my motor specs? Thanks

Ayuh,.... Marine motors Don't use vacuum secondaries...

I don't do Holley's, so I don't know what to tell ya...

'n 4 to 6psi is standard fair for carbed motors...

 

[achris]

Re: Fuel issue Marine Power 5.7

Ayuh,.... Marine motors Don't use vacuum secondaries...

I don't do Holley's, so I don't know what to tell ya...

'n 4 to 6psi is standard fair for carbed motors...

Trash-can the Holley and put a Edelbrock 1409 on instead.... Much better...

 

[John_S]

Re: Fuel issue Marine Power 5.7

I don't know Holleys either, but what is the symptom that has you looking at the secondary fuel nozzles? A lean bog just as they open?

 

[AS19-1]

Re: Fuel issue Marine Power 5.7

The reason I am looking at the secondaries is because I have no increase in power after 3600 rpm when they open and can only reach 4000 rpm. Engine is leaning out secondary plates are opening but no fuel from secondary nozzles. Anti siphon at tank is good and even tried with fuel cap off to see if it was a vent issue. Also replaced filter.

Bond-o I thought most carbed engines did use vacuum secondaries not mechanical secondaries for better economy.

 

[John_S]

Re: Fuel issue Marine Power 5.7

I am sure you checked the 2ndary float setting. What is your engine vacuum? 3600 seems high for just starting to open. I though the "standard" spring started to open around 2K rpms, but it has been a very long time since I have looked at Holleys. Hopefully, someone with more experience will jump in.

 

[AS19-1]

Re: Fuel issue Marine Power 5.7

Yes I checked the float. I was also curious as to when they opened but figured it would be after cruising rpm. I cruise at 3200. I think I am going to connect a fuel pressure gauge. Thanks for your replies

 

[John_S]

Re: Fuel issue Marine Power 5.7

I thought there use to be a graph, but could only find this table:

http://www.holley.com/data/Products/Technical/199R8219-2.pdf

 

[Tahorover]

Re: Fuel issue Marine Power 5.7

Ayuh,.... Marine motors Don't use vacuum secondaries...

I don't do Holley's, so I don't know what to tell ya...

'n 4 to 6psi is standard fair for carbed motors...