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Re: Jet Size
Posted: Mon Nov 04, 2019 9:26 pm
by Big Block Power
I personally and I'll go out on a limb Matt would say change the power valve first. Small steps young jedi!
Re: Jet Size
Posted: Mon Nov 04, 2019 9:28 pm
by shrfdeputy
Big Block Power wrote: Mon Nov 04, 2019 9:26 pm
I personally and I'll go out on a limb Matt would say change the power valve first. Small steps young jedi!
That’s what we decided on I think. We can change those super quick and see what happens. This all started with blown power valves imo so that’s where I want to start.
Re: Jet Size
Posted: Mon Nov 04, 2019 9:35 pm
by Big Block Power
shrfdeputy wrote: Mon Nov 04, 2019 9:28 pm
Big Block Power wrote: Mon Nov 04, 2019 9:26 pm
I personally and I'll go out on a limb Matt would say change the power valve first. Small steps young jedi!
That’s what we decided on I think. We can change those super quick and see what happens. This all started with blown power valves imo so that’s where I want to start.
Yep agreed. If all else fails let's convert it to EFI!
Re: Jet Size
Posted: Mon Nov 04, 2019 9:37 pm
by shrfdeputy
Big Block Power wrote: Mon Nov 04, 2019 9:35 pm
shrfdeputy wrote: Mon Nov 04, 2019 9:28 pm
Big Block Power wrote: Mon Nov 04, 2019 9:26 pm
I personally and I'll go out on a limb Matt would say change the power valve first. Small steps young jedi!
That’s what we decided on I think. We can change those super quick and see what happens. This all started with blown power valves imo so that’s where I want to start.
Yep agreed. If all else fails let's convert it to EFI!
Lol I knew you’d find a way to spend my money.
Re: Jet Size
Posted: Mon Nov 04, 2019 9:40 pm
by cmattj
Hey just catching this..
As we discussed power valve in your other thread it is also the use of the power valve to increase fuel flow through the metering block when opened under a loss of vacuum ( vacuum under acel drops then the valve opens).
Then with the vacuum achieving a cruise speed increase above 2.5 inches, it will close and cruise on the main jet only. The front uses 62-64 jets depending on elevation.
The secondary ( back ) is a plate instead of a power valve and is only allowed to draw the circuit under “ Wide open “ throttle. They are vacumn operated secondary, and by air bleeds and flow coming the the rear venturies only and won’t have an accelerator pump like the front. The rear take 74-76 as the have no additional help from a power valve circuit.
Swap the jets to the proper location and set the idle screws at 1- 1/2 turns out from in. You’ll be Golden!
Re: Jet Size
Posted: Mon Nov 04, 2019 9:41 pm
by Big Block Power
shrfdeputy wrote: Mon Nov 04, 2019 9:37 pm
Big Block Power wrote: Mon Nov 04, 2019 9:35 pm
shrfdeputy wrote: Mon Nov 04, 2019 9:28 pm
That’s what we decided on I think. We can change those super quick and see what happens. This all started with blown power valves imo so that’s where I want to start.
Yep agreed. If all else fails let's convert it to EFI!
Lol I knew you’d find a way to spend my money.
I just try to help solve issues. Lol
No matter the cost.
Re: Jet Size
Posted: Mon Nov 04, 2019 9:44 pm
by shrfdeputy
cmattj wrote: Mon Nov 04, 2019 9:40 pm
Hey just catching this..
As we discussed power valve in your other thread it is also the use of the power valve to increase fuel flow through the metering block when opened under a loss of vacuum ( vacuum under acel drops then the valve opens).
Then with the vacuum achieving a cruise speed increase above 2.5 inches, it will close and cruise on the main jet only. The front uses 62-64 jets depending on elevation.
The secondary ( back ) is a plate instead of a power valve and is only allowed to draw the circuit under “ Wide open “ throttle. They are vacumn operated secondary, and by air bleeds and flow coming the the rear venturies only and won’t have an accelerator pump like the front. The rear take 74-76 as the have no additional help from a power valve circuit.
Swap the jets to the proper location and set the idle screws at 1- 1/2 turns out from in. You’ll be Golden!
Matt that’s exactly what we thought. Then we got inside it and there were power valves in both the front AND the back. They were both 2.5’s. My guy said something at lunch today about keeping it as an option to block the back one off.
Re: Jet Size
Posted: Mon Nov 04, 2019 10:02 pm
by cmattj
Yeah as blocking requires that jump in jet size. But the metering block may be calibrated for it .
Once you swap the jets you’re idle and off idle circuit will be lean again. I’m no too worried about the secondary’s as your carb is a -1 ( the version number after the 80378 which tells us it’s already a replacement carb but for your application.
Jets in the right spot would have been the ticket.
Now you see why going with Carter or edlebrock is easy. Haaa!
No worries as you have it now!
So some googling on your part number found me this.
Looks like a call to Holley to verify but you may be in the ball bark and possibly still high in front jet.
See the inter web can be amazing.. would have saved my thumb!
Re: Jet Size
Posted: Mon Nov 04, 2019 10:07 pm
by shrfdeputy
cmattj wrote: Mon Nov 04, 2019 10:02 pm
Yeah as blocking requires that jump in jet size. But the metering block may be calibrated for it .
Once you swap the jets you’re idle and off idle circuit will be lean again. I’m no too worried about the secondary’s as your carb is a -1 ( the version number after the 80378 which tells us it’s already a replacement carb but for your application.
Jets in the right spot would have been the ticket.
Now you see why going with Carter or edlebrock is easy. Haaa!
No worries as you have it now!
So some googling on your part number found me this.
Looks like a call to Holley to verify but you may be in the ball bark and possibly still high in front jet.
See the inter web can be amazing.. would have saved my thumb!
So that -1 means the carb has been replaced before? We could definitely tell someone had been inside it before. That graph you found is one of several I found with those numbers today, and it shows two power valves.
Re: Jet Size
Posted: Mon Nov 04, 2019 10:17 pm
by cmattj
shrfdeputy wrote: Mon Nov 04, 2019 10:07 pm
So that -1 means the carb has been replaced before? We could definitely tell someone had been inside it before. That graph you found is one of several I found with those numbers today, and it shows two power valves.
Yes OE usually have no dash although possibly toward the end of the carb era.
The rear being vacuum and not mechanically operated is the reason. Never come into play at idle and cruise speeds.
See you had it ! Let’s see if you can confirm a 56-58 jet. As long as she doesn’t stumble ( lean hesitation) you will be making the trees green again!
Re: Jet Size
Posted: Mon Nov 04, 2019 10:20 pm
by shrfdeputy
cmattj wrote: Mon Nov 04, 2019 10:17 pm
shrfdeputy wrote: Mon Nov 04, 2019 10:07 pm
So that -1 means the carb has been replaced before? We could definitely tell someone had been inside it before. That graph you found is one of several I found with those numbers today, and it shows two power valves.
Yes OE usually have no dash although possibly toward the end of the carb era.
The rear being vacuum and not mechanically operated is the reason. Never come into play at idle and cruise speeds.
See you had it ! Let’s see if you can confirm a 56-58 jet. As long as she doesn’t stumble ( lean hesitation) you will be making the trees green again!
I’m just ready for my transom to be white again.
I will definitely report back when we can get it switched around and tested.
Re: Jet Size
Posted: Tue Nov 05, 2019 6:23 am
by Big Block Power
Man is been a long time since I saw a carb. Sheet. I don't miss it either. Sherif lets get her injected baby. Only way you will get rid of the scum line. Let's do it
Re: Jet Size
Posted: Tue Nov 05, 2019 6:26 am
by shrfdeputy
Big Block Power wrote: Tue Nov 05, 2019 6:23 am
Man is been a long time since I saw a carb. Sheet. I don't miss it either. Sherif lets get her injected baby. Only way you will get rid of the scum line. Let's do it
It didn’t foul up the transom like that when I first bought the boat! And I asked about TBI a few weeks ago! The consensus then was the carb was better!
Re: Jet Size
Posted: Tue Nov 05, 2019 11:01 am
by akorcovelos
Just get a bigger engine to bolt the carb to. Do I need to solve all the problems around here?
Re: Jet Size
Posted: Tue Nov 05, 2019 11:03 am
by shrfdeputy
akorcovelos wrote: Tue Nov 05, 2019 11:01 am
Just get a bigger engine to bolt the carb to. Do I need to solve all the problems around here?
Don’t think I haven’t looked to see if my outdrive would hold a 502.
I will definitely report back when we can get it switched around and tested.