SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: sandaddict on May 16, 2007, 06:52:01 PM
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im wondering what size carb i should be running on my 454? the one i have on there just doesnt seem to be doing the job. dont know what size it is but it is a holley 4 bbl. dont know what the specs are on the engine but he said it was set up for turbo's so i assume its low compression. it supposedly has a small cam and it has an Edelbrock dual plane manafold. thinkin of may be a 750 or 850 dbl pumper? the one thats on it now is only givin me about 3800 rpm. and once in a while when i stomp on it the rpm's will come alive bt ive only had it do that twice. mostly you stomp on it and it sounds like its starving for fuel. anyways just wondering what you guys thought. ;D
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Find out what you have 1st. There are MANY reasons your engine may not be getting enough fuel. From plugged filters to bad lines, to poor fuel pressure caused by these or fuel the pump itself. Your float may not be set correctly on your carb, or the jets may be gummed up and not delivering enough fuel... So as I started with find out what size carb you have and see if it is too small for your application. There is often a metal tab on the carb with the numbers to ID it. Or just put a good pic and I'm sure someone can get close just from looking at it.
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I know on the double pumper Holley's there is a number on the choke's air horn that states "LIST ____", there are four numbers that follow the "LIST". Post those four numbers and I can tell you what it is. However, if the carb is anything different than the double pumper I don't know jack sh!t. Like Chaz said, take a picture or two of it.
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Check your fuel filter! And then make sure your secondaries are opening.
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I started thinking secondaries too, after the once in a while when i stomp on it the rpm's will come alive part. If it has vacuum secondaries and maybe a intake vacuum leak... or they are just sticking ::)
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My boat had a 750 vac sec and ran real good and was relativly good on gas .
-beerjet-
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I have dual 750 vac sec's and it real shitty on gas!
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I have a single Edelbrock 750 w/vac sec. and while I have nothing to compare the "gas mileage" to, It seems like I burn a gallon in about 60sec. at WOT
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thanks guys ill get some pics up tomorrow. it is a vacume secondary but the guy i bought it from put a rivet in the linkage so they would open about 1/4 of the way at WOT. dont know why.
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alringht here we go. i couldnt see all the numbers but i got the pics. anyone know what it is?
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On the top picture, very close to or under the sticker that's on the choke's air horn there should be a LIST number.
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on the first pic where the white sticker is it should have a number on the sticker or under the sticker thats where it is on mine. thecraz
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ok the number was under the sticker. :P
the number is 80508-1
2090
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Sounds like Marc and Chaz got a good carb lesson yesterday maybe ya' could ask them! ;D ;D ;D!
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well from what i can find it is a 750 vac secondary. maybee i just need help tuning it huh?
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put a power valve in it
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??? ??? ???
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thanks guys ill get some pics up tomorrow. it is a vacume secondary but the guy i bought it from put a rivet in the linkage so they would open about 1/4 of the way at WOT. dont know why.
He was trying to limit or restrict the carb, he probably thought it was too big for the engine or he was trying to save gas...
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put a power valve in it
Holley carbs have a power valve in them. As far as I know they are the only brand that has them. It's very common for the power valve to blow out when an engine has backfired.
What's up HDriderTH? ;D
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well im gonna go to Elsinore in the morning and see if i can get this crap worked out. if anyone wants to join me come on out. i guess if the boat dont run i can look at the wifes big cans all day...(:! >:D
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i guess if the boat dont run i can look at the wifes big cans all day...(:! >:D
This post is worthless without pics . Until I can approve the cans , theres no guarrantee you'll have a good day. :P
-beerjet-
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I could agree with BJ more....F the carb...wheres the cans???
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I agree, wheres the cans? ANd how big? ;Dhahahahhahaha
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(.)(.) :P
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well, did it run or do your eyes hard.
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(.)(.) :P
Nips are kinda low....
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i was kind of hoping for something like this ...
( @ Y @ )
But hey , what the hell right . You get stare at them all day .
-beerjet-
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i think those are a little closer ;D you guys could see for your self if you actually floated them squirt guns instead of just drink beer and talk about it! O0
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i think those are a little closer ;D you guys could see for your self if you actually floated them squirt guns instead of just drink beer and talk about it! O0
Good point ! I'll shoot for next weekend . Asuming I get my pump back in time .
-beerjet-
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ditch the carb. and go injection
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ill tel you what ... if you foot the bill ill go injection without hesitation ;D
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I would put a merk on it, and foot the bill. But to late, you didn't show the cans! ;D haha
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I would put a merk on it, and foot the bill. But to late, you didn't show the cans! ;D haha
id rather sink it than hang one of them damn things off it. >:D
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well i finally got all the parts i needed and rebuilt the damn carb. diaphram for the vacume secondaries was no good. changed the power valve. put the power valve protection kit in it, and a quick change spring kit for the secondaries. sounds great now out of the water but we'll see what happens when i float it >:D
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I was asking my guy who built my Olds motor about what size carb to use and he said most guys get them wrong because jets love CFM's but not all that fuel so he uses large size carb and cut down the fuel circuit side some and my carb seems to be right on the money. I have great performance and good mileage for what it is as long as I keep my foot out of it somewhat and I do not know the size of it but it's double feed with mechanical sec and I think it is an 850 with smaller jets with an wooden spacer between it and the manifold.
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A wooden carb spacer? Got a picture? ???
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I think I might have a picture and I will try to figure out how to post it. the purpose of it is to keep the heat away from the carb that the intake produces. When I got my motor back from my engine guy I couldn't believe what I was seeing and he told me that was the reason.
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A wooden carb spacer? Got a picture? ???
They work great, we use them to adapt from a 4v manifold to run a 2v carb on circle track race cars.
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455 olds with a 1408 Edelbrock which i think is a 750 cfm carb. Engine is .30 over with Edelbrock Torker intake Good, bad. Sorry not trying to hijack. This is something i to have been wondering about myself. C'mon guys let me know if its the right set up.
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