Spare Carb Anyone??

**MAD GREEK** · 11-15-2010, 09:52 PM

Hey guys.. ran my boat for the first time this weekend. didnt end too well. came to the conclusion that the carb is dumping too much fuel in the motor. It has a 750 holley vacuum secondary on it right now. A lot of guys are saying that carb is fine, the guy i bought it from is saying there could be a problem with it. I trust his judgment, but live far away from him and am curious to see if anyone has a spare carb they would let me test. I got a bone stock sbc 350 motor. Have no problem loaning the money as a deposit, just want to rule out if thats the problem before i spend money buying a new one.
I live in Corona, if any of you know Mouzer, im right down the street and am close with him.
Let me know if you have anything for me...
Thank you very much

Troy Moore

**Blowncat 509** · 11-16-2010, 11:35 AM

check your needle and seat assemblies/float levels and power valve!
these carbs are simple and modular, if your power valve is blown, it will go
into full rich mode, and probably foul your plugs- first thing I would do is pull your bowl level plugs and see if you have fuel pouring out! if you do,
it's your n&s- if it loads up at idle, prob your PV- CHECK IT OUT better to
learn how it works than to keep swapping out carbs! good luck

**MAD GREEK** · 11-16-2010, 12:44 PM

Originally Posted by Blownjet 468

check your needle and seat assemblies/float levels and power valve!
these carbs are simple and modular, if your power valve is blown, it will go
into full rich mode, and probably foul your plugs- first thing I would do is pull your bowl level plugs and see if you have fuel pouring out! if you do,
it's your n&s- if it loads up at idle, prob your PV- CHECK IT OUT better to
learn how it works than to keep swapping out carbs! good luck

Yea defiantly want to learn how it all works. Float bowl levels are fine and runs fine at an idle. Only craps out at around 3k but never clears up. And yes, plugs are fouled.. The guy I bought the motor from was thinking power valve too but it doesn't really backfire through the intake, mainly through the exhaust

**Widetrack** · 11-16-2010, 03:59 PM

Originally Posted by KeepItOn1 Productions

Yea defiantly want to learn how it all works. Float bowl levels are fine and runs fine at an idle. Only craps out at around 3k but never clears up. And yes, plugs are fouled.. The guy I bought the motor from was thinking power valve too but it doesn't really backfire through the intake, mainly through the exhaust

Backfire through exhaust is from fouled plugs! Or a flat lobe on the cam! The Holley carbs are pretty easy to work on! You can do it lay out a towel and start taking it apart checking jets for trash, water in fuel gunk etc. Take your time and blow through all ports. Then put it back together! They have a good Holley book that has good info.too!

**Coolchange** · 11-16-2010, 07:46 PM

82% of all fuel problems are electrical

**submakr** · 11-16-2010, 08:47 PM

You are way over carbed for a "bone stock SBC 350." You should be in the 600 cfm range!!

**MAD GREEK** · 11-16-2010, 10:17 PM

Originally Posted by submakr

You are way over carbed for a "bone stock SBC 350." You should be in the 600 cfm range!!

motor ran with the exact same carb on it.. this one was just on the shelf.

**Rvrrat350** · 11-16-2010, 11:36 PM

Originally Posted by submakr

You are way over carbed for a "bone stock SBC 350." You should be in the 600 cfm range!!

my boat has a 350 with a 600cmf holly and runs great
my old jet boat had a mildly built 360 with a 650 and also ran great
i think a 750 is a lil to big for the small block
Good luck with the boat

**MAD GREEK** · 11-17-2010, 10:33 AM

Originally Posted by Rvrrat350

my boat has a 350 with a 600cmf holly and runs great
my old jet boat had a mildly built 360 with a 650 and also ran great
i think a 750 is a lil to big for the small block
Good luck with the boat

Yea ok.. Rebuilt the carb last night. We'll seemhow it works this weekend. If all else fails, I'll throw a 600 or 650 on and see what happens

**Beer:30** · 11-17-2010, 10:44 AM

Originally Posted by KeepItOn1 Productions

Yea ok.. Rebuilt the carb last night. We'll seemhow it works this weekend. If all else fails, I'll throw a 600 or 650 on and see what happens

You should be just fine. I ran a 327 with a 3310 780 vac sec for YEARS. No problem at all. If it were a double-pumper (mech sec), I could see it being a bit much. But, for a boat, you're fine. The vac secs only open AS THE ENGINE NEEDS IT. So, if it doesn't need FULL secs, it won't.

Don't forget the electrical - as mentioned earlier. If you are losing voltage, the ignition system won't support much RPM. You could just be losing spark starting near 3000.

**MAD GREEK** · 11-17-2010, 11:33 AM

Originally Posted by Beer:30

Don't forget the electrical - as mentioned earlier. If you are losing voltage, the ignition system won't support much RPM. You could just be losing spark starting near 3000.

How would i check that? Is there a way? The distributor was given to me so it could be a possibility. I'm not running an altinator, but the battery has 12.70 volts and keeps it when running.

**Beer:30** · 11-17-2010, 12:01 PM

Originally Posted by KeepItOn1 Productions

How would i check that? Is there a way? The distributor was given to me so it could be a possibility. I'm not running an altinator, but the battery has 12.70 volts and keeps it when running.

Mainly, you SHOULD be running 14.1-14.7 volts whilest underway. So, I would suggest running an alternator.

If you have an electric fuel pump, this is also drawing current and could hinder your ignition.

What type of distributor? If large-cap HEI, the module OR coil OR both could be breaking down. Since you are fouling plugs, I would say coil.

If points-type: Same thing, would likely be coil. However, I would get a Pertronix IgnitorII or III module if that were the case along with matching coil. It bolts in place of the points, you DITCH the voltage reducing resistor (12v to 9v) AND it has a built in rev-limiter!

**MAD GREEK** · 11-17-2010, 12:24 PM

1st off, my bad.. I meant it holds the 12.7 after running, not during.
2nd, it's the HEI style

It's kinda all makin some sense.. Carb seemed fine when I rebuilt it last night. I guess I'll look into the ignition. Any way of testing it, or just put a new one on?

**Beer:30** · 11-17-2010, 12:36 PM

Originally Posted by KeepItOn1 Productions

1st off, my bad.. I meant it holds the 12.7 after running, not during.
2nd, it's the HEI style

It's kinda all makin some sense.. Carb seemed fine when I rebuilt it last night. I guess I'll look into the ignition. Any way of testing it, or just put a new one on?

HEI tune-up kits are cheap and available at your local parts store. It'll have a cap, rotor, module. Coil would be extra. MSD and ACCEL have "performance" tune up kits. Pertronix also and Davis Unified Ignition (DUI).

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Spare Carb Anyone??

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