SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: Redeye1620 on April 15, 2014, 07:33:05 PM
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I replaced the old Qudrajet carb with a new Eldebrock 650cfm on my 455 Olds. My problem is with the throttle cable. From where the cable mounts to the engine & out to the end that attaches to the carb, the Edelbrock is 2" closer to the front of the engine. Or the cable that opens & closes the carb is 2" to long. (my cable wraps around & mounts on the front of the engine.) Thus I cannot get the carb to idle down. Do you know of anybody who makes a throttle linkage extenstion for the Edelbrock carbs? I saw the Ford adapter, but it doesn't look like it will solve my problem. I need to move the cable attachment, on the linkage, back 2".....Thanks in advance for your expertise....-Rich
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Buy one of these, install it between the carb and manifold, attach the throttle cable to it. DONE
Super simple!
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I replaced the old Qudrajet carb with a new Eldebrock 650cfm on my 455 Olds.
Had a shitty day. So excuse me if this sounds negative... Why would go from 780 CFM down to 650? :screwy: :screwy: :screwy: :screwy:
My problem is with the throttle cable. From where the cable mounts to the engine & out to the end that attaches to the carb, the Edelbrock is 2" closer to the front of the engine.
Sounds about right. The Carter and the Rottenchester are two completely different animals.
Or the cable that opens & closes the carb is 2" to long. (my cable wraps around & mounts on the front of the engine.) Thus I cannot get the carb to idle down. Do you know of anybody who makes a throttle linkage extenstion for the Edelbrock carbs?
Can you convert it to mount on the rear of the engine and run the cable off the other side? Without a picture being worth the thousands words, I need a thousand words... ???
I saw the Ford adapter, but it doesn't look like it will solve my problem. I need to move the cable attachment, on the linkage, back 2".....Thanks in advance for your expertise....-Rich
Whose bracket do you have, Holley Marine makes several different ones..
GT
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Had a shitty day. So excuse me if this sounds negative... Why would go from 780 CFM down to 650? :screwy: :screwy: :screwy: :screwy:
Sounds about right. The Carter and the Rottenchester are two completely different animals.
Can you convert it to mount on the rear of the engine and run the cable off the other side? Without a picture being worth the thousands words, I need a thousand words... ???
Whose bracket do you have, Holley Marine makes several different ones..
GT
The bracket I have is stock factory from Hardin Marine. It bolts to the left front of the intake manifold. If I move the cable to the rear of the engine, buying a shorter new cable, then I will be 2" too close to the throttle linkage.
The engine is a new rebuild in a 22" day cruiser. I went with the Edelbrock carb because my RPMs are limited to 5,000 due to the limits of the stock Jacuzzi YJ pump. The guy at Summit recommended it saying my low end throttle response would improve.
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Buy one of these, install it between the carb and manifold, attach the throttle cable to it. DONE
Super simple!
Can this be used with the morse style cable? If so you have solved my problem Rushin. Thanks....-Rich
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Can this be used with the morse style cable? If so you have solved my problem Rushin. Thanks....-Rich
Yes, I use those with morse cables ALL the time. If you search on eBay, there's sellers who sell them with the square style fork, for other cables. The clamp you want is a hinge, the cable slides in at the 1/8" channel and the hinge locks the cable in place.
If you need a picture explanation, just let me know, I'll take a picture of one I have at the shop.
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My 2 cts: Return it to Summit. You're going to need a bigger carb for the Olds. Throttle response isn't an issue with a jet boat. Go with a double-pumper 850 Holley or Quickfuel (marine versions).
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Buy one of these, install it between the carb and manifold, attach the throttle cable to it. DONE
Super simple!
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I have one of those laying around. If you want it it's your bro. I also have a 750 Edelbrock sitting around that's got a fresh rebuild. You can have the bracket for free.
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I agree with larger carb... Seen many olds run super lean because of small carbs...
Only a matter of time until you change to a larger carb. It's inevitable.
The change will come sooner than later with your large boat.
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I agree with larger carb... Seen many olds run super lean because of small carbs...
Only a matter of time until you change to a larger carb. It's inevitable.
The change will come sooner than later with your large boat.
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Thanks for the offer. But I think I solved the problem with a "cable extenstion" from Elderbrock.
http://www.amazon.com/gp/product/B00062YA9E/ref=oh_details_o00_s00_i00?ie=UTF8&psc=1 (http://www.amazon.com/gp/product/B00062YA9E/ref=oh_details_o00_s00_i00?ie=UTF8&psc=1)
I may take you up on the carb offer. What are you asking, & include shipping to 95677.
Thanks to all who enlightened me....-Rich
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150 bucks. With the bracket.
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I agree with larger carb... Seen many olds run super lean because of small carbs...
Can you explain how a carb with less airflow capability runs leaner than one that can flow more air?
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Can you explain how a carb with less airflow capability runs leaner than one that can flow more air?
All ears here too... ;)
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Can you explain how a carb with less airflow capability runs leaner than one that can flow more air?
Smaller carb, smaller supplied jets...smaller jets less fuel. Less fuel=lean!
Flow chart off?
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Smaller carb, smaller supplied jets...smaller jets less fuel. Less fuel=lean!
Flow chart off?
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Sorry no.
The only reason a smaller carburetor will run lean is if it was never jetted correctly to start with.
I would have an easier time believing there was an un-adjustable lean is when the carburetor is "too large". Insufficient velocity and incorrect venturi nozzles would be the cause. Smaller venturi, higher velocity, more fuel.
There should be zero issues meeting stoichiometric mixtures with a little bitty..
GT
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Sorry no.
The only reason a smaller carburetor will run lean is if it was never jetted correctly to start with.
I would have an easier time believing there was an un-adjustable lean is when the carburetor is "too large". Insufficient velocity and incorrect venturi nozzles would be the cause. Smaller venturi, higher velocity, more fuel.
There should be zero issues meeting stoichiometric mixtures with a little bitty..
GT
I don't remember the op saying he had a correctly jetted 650 carb, did I miss something?
GT, I disagree with you...wouldn't be the first time.
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I don't remember the op saying he had a correctly jetted 650 carb, did I miss something?
GT, I disagree with you...wouldn't be the first time.
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Then how does a restrictor plate engine run like it's scared... They don't lean out. ;)
I love it when people disagree with me... No really I do.
Did you notice you didn't back it up?
If I pull a carburetor off of a properly running four cylinder houseboat motor and bolted it to a 496 Chevy, all things being equal, it will not run lean. But it sure will be anemic.
GT
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Then how does a restrictor plate engine run like it's scared... They don't lean out. ;)
I love it when people disagree with me... No really I do.
Did you notice you didn't back it up?
If I pull a carburetor off of a properly running four cylinder houseboat motor and bolted it to a 496 Chevy, all things being equal, it will not run lean. But it sure will be anemic.
GT
http://auto.howstuffworks.com/auto-racing/nascar/nascar-basics/nascar-safety4.htm
This article states points contrary to what you indicate.
Also, don't know if you noticed, I don't post here much...especially in terms of in depth subjects such as this one...I don't need to write out a lengthy explanation of my view point ( like others do ) for you or any else to immediately jump to a conclusion that isn't factual!
Truthfully, you know as well I I do, that an out of the box afb 650 will not run right on a 455 in a heavy jet boat. Call it anemic if you'd like...
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http://auto.howstuffworks.com/auto-racing/nascar/nascar-basics/nascar-safety4.htm (http://auto.howstuffworks.com/auto-racing/nascar/nascar-basics/nascar-safety4.htm)
This article states points contrary to what you indicate.
Also, don't know if you noticed, I don't post here much...especially in terms of in depth subjects such as this one...I don't need to write out a lengthy explanation of my view point ( like others do ) for you or any else to immediately jump to a conclusion that isn't factual!
Truthfully, you know as well I I do, that an out of the box afb 650 will not run right on a 455 in a heavy jet boat. Call it anemic if you'd like...
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Well I hate to say it, but your link 100% confirms what I just said. " Restrictor plates are placed between the carburetor and the intake manifold to reduce the flow of air and fuel into the engine's combustion chamber, thus reducing horsepower and speed."
Did I say or do something to piss you off?
For the record, the air flow "pulls" the fuel into the engine, less air, less fuel. I have a pretty good understanding of how a carburetor works. For that matter EFI. I was not saying a 650 CFM carburetor was the right choice on a 455, what I did say was that it will not run lean.
I also piggy backed onto what lbhsbz stated, you're not pissing in his Corn Flakes... :-\ WTF?
GT
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Also too, I type almost as fast as I can talk, so that's why you get to experience verbal vomit at times.
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Well I hate to say it, but your link 100% confirms what I just said. " Restrictor plates are placed between the carburetor and the intake manifold to reduce the flow of air and fuel into the engine's combustion chamber, thus reducing horsepower and speed."
Did I say or do something to piss you off?
For the record, the air flow "pulls" the fuel into the engine, less air, less fuel. I have a pretty good understanding of how a carburetor works. For that matter EFI. I was not saying a 650 CFM carburetor was the right choice on a 455, what I did say was that it will not run lean.
I also piggy backed onto what lbhsbz stated, you're not pissing in his Corn Flakes... :- WTF?
GT
GT, your not pissing me off...
You said that restrictor plate engines run like they are scared...
My understanding of that analogy is " fast"
Reducing horsepower and speed is quite opposite, no?
Also, what makes a 650cfm carb a wrong choice for a 455?
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Also too, I type almost as fast as I can talk, so that's why you get to experience verbal vomit at times.
Wish I could do that!! By the time I write one sentence, I have to correct it 10 times and loose the rest of what I am trying to express
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Then how does a restrictor plate engine run like it's scared... They don't lean out. ;)
I love it when people disagree with me... No really I do.
Did you notice you didn't back it up?
If I pull a carburetor off of a properly running four cylinder houseboat motor and bolted it to a 496 Chevy, all things being equal, it will not run lean. But it sure will be anemic.
GT
lol make one hell of a governor on a 496 air pump
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Wish I could do that!! By the time I write one sentence, I have to correct it 10 times and loose the rest of what I am trying to express
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I virtually type for a living sometimes writing 20 page reports on equipment condition and all my work orders are all via computer.
I also do a bit of DDC programming and play with computers days at a time.
What I was saying about the restrictor plate engines running like they are scared, I was basically speaking in terms of they run the same, but with less airflow, that also reduces the fuel flow, the only thing that happens is they make less poo poo... But they do not lean out.
The reason a 650 CFM carburetor is the wrong choice IMHO is that it will be under carbureted for the hp requirements of the jet pump. An automotive engine will seldom if ever see 5,000 RPM for hours at a time. Which is why it would perfectly fine for a station wagon.
The idea on sizing a carburetor on a jet is to lower the manifold pressure enough to keep the VE at it's maximum point possible. The closer to atmospheric pressure you get on a WOT motor, the higher the volumetric efficiency.
Hope that came out right. :(
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I virtually type for a living sometimes writing 20 page reports on equipment condition and all my work orders are all via computer.
I also do a bit of DDC programming and play with computers days at a time.
What I was saying about the restrictor plate engines running like they are scared, I was basically speaking in terms of they run the same, but with less airflow, that also reduces the fuel flow, the only thing that happens is they make less poo poo... But they do not lean out.
The reason a 650 CFM carburetor is the wrong choice IMHO is that it will be under carbureted for the hp requirements of the jet pump. An automotive engine will seldom if ever see 5,000 RPM for hours at a time. Which is why it would perfectly fine for a station wagon.
The idea on sizing a carburetor on a jet is to lower the manifold pressure enough to keep the VE at it's maximum point possible. The closer to atmospheric pressure you get on a WOT motor, the higher the volumetric efficiency.
I'm mostly on my phone typing, so it's not as convenient as an actual keyboard...not that a keyboard for is much better 😜
Let's agree to disagree. I'm sure one day when we meet in person, we can discuss in more detail...
Iv had two customers whose motors had burnt valves... Both times they were running 600cfm carbs.
With my experience, I blame the carbs in both instances.
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In those two cases, more than likely either never set up properly or the added manifold vacuum made very evident a gigantic vacuum leak.. Aluminum intake manifolds? Very few people, especially shade tree mechanics, know how to properly torque down a manifold.
Purely speculation, but bet I'm in the park.. However betting against being too small of carburetor, there is just no scientific evidence to support it. I have never heard of such a thing. Not saying impossible mind you, just can't make it work in my head.
GT
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In those two cases, more than likely either never set up properly or the added manifold vacuum made very evident a gigantic vacuum leak.. Aluminum intake manifolds? Very few people, especially shade tree mechanics, know how to properly torque down a manifold.
Purely speculation, but bet I'm in the park.. However betting against being too small of carburetor, there is just no scientific evidence to support it. I have never heard of such a thing. Not saying impossible mind you, just can't make it work in my head.
GT
One engine was running an aluminum "performer" the other one was running a complete stock engine with the only change being from a quadrajet to an edelbrock ( initial reason why this topic peaked my interest ). When the first engine was rebuilt, I made sure to up the carb. Engine is heading into it's second season running solid.
If we go by your previous example, air draws fuel in... Which I agree with. Then if there is less air being drawn in, then there is less fuel too...
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One engine was running an aluminum "performer" the other one was running a complete stock engine with the only change being from a quadrajet to an edelbrock ( initial reason why this topic peaked my interest ). When the first engine was rebuilt, I made sure to up the carb. Engine is heading into it's second season running solid.
If we go by your previous example, air draws fuel in... Which I agree with. Then if there is less air being drawn in, then there is less fuel too...
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Correct, air fuel ratio... Should be 14.7:1 air to fuel, the ratio should be fairly constant with the exception of hard acceleration.
GT
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Thank you for the education. A little history, my barge is a 21' day cruiser, family boat that will never see 50 mph. The engine is spinning a stock Jacuzzi YJ pump. Fully loaded it tips the scales around 3,000-3,500 lbs. Because of the weight of the boat & the pump's limitations, I am bascially limited to 5500 rpms. So I didn't build the engine to max horse power, but more for economy & low end torque. This is why the choice of a Edelbrock 650 carb.
As to tuning it, I will be out on the lake Mother's Day weekend with my new jets, springs & metering rods.
BTW the cable extension from Edelbrock worked like a charm. Cut it to length & all is good.
Thank you all for sharing your knowledge & experences....-Rich