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Discussion Starter · #1 ·
Brief history...I took a 4150 off my 557, and put on a 2 circut 8082, first time out I lost 300 r's with no other changes. From there I pulled a couple of plugs(looked rich) transom was also blacker than normal. Sooo I dropped 4 jets in the secondaries, and put on my dry headers with a wideband 02.. Fast fwd to today boat seemed to run fine while in the primaries,seemed to rich at cruise 12.5-13,but as soon as I'd stab it it would go scary lean for second(like off the wideband lean, and just ran like chit. It was prolly 13.5 ish at wot. The weird part is when I eased off the go pedal it would clean up and run better/faster. Is that because vac increased and the pv richened things up or??? I guess I'll jet it back to where it was but ...even that ran worse than the smaller carb. Any sugestions???
 

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Well, you didn't really say what the cfm ratings were on either carb. Also, Holleys come with jets pretty close to what they need, but if you change them, only go a max of 2 sizes at a time. Also, you should change all 4 of them not just the secondaries.The primaries are usually 6to8 sizes smaller than the secondaries, as the powervalve adds fuel to the primary mixture when it opens. Use a vacuum gauge to determine at what vacuum the mixture goes lean. check the number on your power valve. a 6.5 will open when the vacuum drops to 6.5 inches of vacuum. you may need to raise the number on the power valve to open sooner. First you should go back to the original secondary jets and check the power valve size.Generally, the power valve number should be1 to 1.5 numbers lower than your vacuum reading at idle. Or just put the other carb back on.
 

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The power valve richens things up when the vaccume DEcreases, not increases. Increased vaccume shuts the power valve off, once it reaches the set point of the PV.

IMO at least take the secondaries back 2 sizes, perhaps all 4 and see where that puts you before you melt something.
 

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If it goes lean for a second when you stab it, I would say you don't have enough accelerator pump. If it picks up speed as you let out of the throttle, I would say it is to lean.
Sometimes things defy logic. The wideband is telling you one thing, the motor may be saying different. Don't be afraid to try things opposite of what you think it might need.
 

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Discussion Starter · #5 · (Edited)
Well, you didn't really say what the cfm ratings were on either carb. Also, Holleys come with jets pretty close to what they need, but if you change them, only go a max of 2 sizes at a time. Also, you should change all 4 of them not just the secondaries.The primaries are usually 6to8 sizes smaller than the secondaries, as the powervalve adds fuel to the primary mixture when it opens. Use a vacuum gauge to determine at what vacuum the mixture goes lean. check the number on your power valve. a 6.5 will open when the vacuum drops to 6.5 inches of vacuum. you may need to raise the number on the power valve to open sooner. First you should go back to the original secondary jets and check the power valve size.Generally, the power valve number should be1 to 1.5 numbers lower than your vacuum reading at idle. Or just put the other carb back on.
Fwiw the one I took off was a 800 dp(#9022) this one is a 1050. I have a vac gauge installed permanent. My old carb had a pv just on the primary side. This one has a pv in the secondaries, and I assume the primarys but I haven't pulled that bowl yet. I already put the 4 jet sizes back in the secondarys, but that's still sucking wind from where I was with the 800. I'm pretty sure I lit off a couple of ping bombs too. As far as the pv thing goes....I'm not sure how to use the vac gauge to diagnose/pick the secondary side of things. I'll try to put up a vid of the wide band.
 

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Fwiw the one I took off was a 800 dp(#9022) this one is a 1050. I have a vac gauge installed permanent. My old carb had a pv just on the primary side. This one has a pv in the secondaries, and I assume the primarys but I haven't pulled that bowl yet. I already put the 4 jet sizes back in the secondarys, but that's still sucking wind from where I was with the 800. I'm pretty sure I lit off a couple of ping bombs too. As far as the pv thing goes....I'm not sure how to use the vac gauge to diagnose/pick the secondary side of things.
I'm not nessesarily recommending this, but you can buy a plug to replace the secondary pv and increase the secondary jets 6 to 8 sizes. What rpm are you turning? that's a big carb unless you have a pretty big cam and get it up towards 7000 rpm. Just so you know, I'm pretty new to the boat world-most of my knowledge comes from 30 years of running holleys on my street and drag cars. Some things seem to be boat specific.Make sure there is no vacuum leak at the adaptor you have between your carb and manifold. In fact I have heard it's not such a good idea to put a 4500 series carb on a manifold designed for a 4150.Disrupts the airflow I think.
 

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Discussion Starter · #7 ·
I'm not nessesarily recommending this, but you can buy a plug to replace the secondary pv and increase the secondary jets 6 to 8 sizes. What rpm are you turning? that's a big carb unless you have a pretty big cam and get it up towards 7000 rpm. Just so you know, I'm pretty new to the boat world-most of my knowledge comes from 30 years of running holleys on my street and drag cars. Some things seem to be boat specific.Make sure there is no vacuum leak at the adaptor you have between your carb and manifold. In fact I have heard it's not such a good idea to put a 4500 series carb on a manifold designed for a 4150.Disrupts the airflow I think.
Fwiw the manifold is for a 4500(tall deck)..I had to run an adapter to put the 4150 on. I was turning 53-5400 with the 4150 dp. I haven't seen over 5k with the domi. I don't even want to say what the tach looked like today.:)sphss
 

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Fwiw the manifold is for a 4500(tall deck)..I had to run an adapter to put the 4150 on. I was turning 53-5400 with the 4150 dp. I haven't seen over 5k with the domi. I don't even want to say what the tach looked like today.:)sphss
What is your cam lift/duration?
 

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holley made that carb in a 8082-1 -2 -3 if you look here on the tech link under holley list numbers you can get the carb back to original specs it list all the jets and pv
to me sounds like a fuel delivery problem can you post a pic of your setup, what kind of pump and reg system and line sizes.what fuel pressure are you running @wot

check needle and seats for proper size, i run -10 from pump to y-block and pair of -8 to carb with a carter 172 gph mech pump full flow no reg

what happens when you adjust air/fuel screws all the way in does the engine die?
dont assume your fuel bowls are full @ wot just because they are at idle it's about flow rates and pressure
hope this is some help.
 

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steelcomp was here
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That carb should run real good right out of the box. Get it back to stock and check to see that everything is functioning properly. Check to see which dash number it is. Make sure the PVs aren't blown.
The 8082 has 84 jets pri and sec., and a 65pv in the pri., none in the sec.
The 8082-1 has 88 jets pri and sec, and 65 pv's pri and sec.
The 8082-2 went back to the 84/84's with 65 pv pri and sec.
They all use .35 squirters.
 

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Discussion Starter · #11 ·
holley made that carb in a 8082-1 -2 -3 if you look here on the tech link under holley list numbers you can get the carb back to original specs it list all the jets and pv
to me sounds like a fuel delivery problem can you post a pic of your setup, what kind of pump and reg system and line sizes.what fuel pressure are you running @wot

check needle and seats for proper size, i run -10 from pump to y-block and pair of -8 to carb with a carter 172 gph mech pump full flow no reg

what happens when you adjust air/fuel screws all the way in does the engine die?
dont assume your fuel bowls are full @ wot just because they are at idle it's about flow rates and pressure
hope this is some help.
Thanks for the suggestions all.. I started thinking on the way home I didn't look back at the fuel pres. gauge at wot. As far as my set up it's a clay smith mech,through-8 lines, regulator is a cheapie holley that is set at 6 psi(at idle). At idle the front bowl level looked a hair low while the back dribbled out when I pulled the plug. At first I thought maybe it was set a hair to high and when I stabbed it it was running dirty. If I eased into the throttle it didn't seem to sound quite as bad. I guess I was getting a lean pop(maybe even a ping or 2) a fellow boater/board member could hear me popping all the way from the other side of the lake. I've already put it back the way it was.....but as mentioned the smaller carb ran quite a bit better according to the tach. I'm not positive if I know where the fuel/air screws are. Should it die if they are all the way in?? Are the the 4 screws on the metering blocks. I'll try to get her back out today if I can get permission from the warden. After all it's supposed to break 50* today.:)sphss
 

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take the fuel reg out of the system. and retest, my carter mech race pump only has 8 lb of pressure so i dont need a reg.... but i did run one and had the same problems you are having,took the reg off and runs fine.
 

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Thanks for the suggestions all.. I started thinking on the way home I didn't look back at the fuel pres. gauge at wot. As far as my set up it's a clay smith mech,through-8 lines, regulator is a cheapie holley that is set at 6 psi(at idle). At idle the front bowl level looked a hair low while the back dribbled out when I pulled the plug. At first I thought maybe it was set a hair to high and when I stabbed it it was running dirty. If I eased into the throttle it didn't seem to sound quite as bad. I guess I was getting a lean pop(maybe even a ping or 2) a fellow boater/board member could hear me popping all the way from the other side of the lake. I've already put it back the way it was.....but as mentioned the smaller carb ran quite a bit better according to the tach. I'm not positive if I know where the fuel/air screws are. Should it die if they are all the way in?? Are the the 4 screws on the metering blocks. I'll try to get her back out today if I can get permission from the warden. After all it's supposed to break 50* today.:)sphss
Yeah, the four screws on the metering blocks are the idle mixture screws. And yes, it should die when they are closed all the way.Turn each one in until the engine starts to stumble, then open it up a half turn or so from there. Do them one at a time.Start with the screws turned out one and a half turns.If it doesn't die when you turn in the idle screws,,you may have the throttle open too far for the idle circuit to function and fuel could be drawn out of the venturies,keeping it running. Keep in mind the 4500 carbs have an idle adjustment(rpm) for the secondarys also. But none of this should effect wot.Sounds like fuel delivery or more likly a vacuum leak at the base of the carb.Spray a couple of small sqirts of starting fluid at the base gasket and see if the rpm picks up.
 

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Discussion Starter · #14 · (Edited)
I'm stumped...ran it today with a pair of 90's in the secondaries...same deal. I'm going to put up a vid if it takes me all day. Fuel pres never stumbles below 6psi. Boat runs killer to about 4500 r's then when I get into the last inch or so of pedal it completely falls apart. Pop pop popopopopopp.
I guess it might be time for the compression tester...
http://www.youtube.com/watch?v=KoL8q3H1Txw
It kind of sounds like wind but at the 4-5 sec mark, that sound is my motor ....
Here is another vid..
http://www.youtube.com/watch?v=SX24ApEgqmY
Btw the compression test was fine....I'm stumped?
 

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steelcomp was here
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It's sounding like it's leaning out. Running out of fuel. Where are you checking your fuel pressure? Have you looked at the needles and seats? Also, make sure the bowl vents are open and clear.
This is probably why who ever sold this carb, sold it.
 

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Discussion Starter · #16 ·
It's sounding like it's leaning out. Running out of fuel. Where are you checking your fuel pressure? Have you looked at the needles and seats? Also, make sure the bowl vents are open and clear.
This is probably why who ever sold this carb, sold it.
I'll try to put up a closer pic, btw the carb is brand new...
 

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Sounds like your timing may be way retarded. Just for giggles, turn the dist. while at wot and see what happens.Is your dist. locked out or does it have advance to it?If it is locked out and you are reading your timing at idle, then it won't wind up 'cause it won't advance. Set your timing for TOTAL timing with a dial timing light.Rev it up near 3000 rpm and set the timing light to your desired total timing and read it at the zero mark.
 

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Discussion Starter · #20 ·
Here is my junk...come to think of it the pres gauge is on the 90* an fitting that goes to the primary side.....
 
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