Merc 470 & Rochester quadrajet problem: flooding

[duduk]

Hello, i hope someone can help me


Merc 470 & Rochester quadrajet problem: flooding


my problem

i have a 1986 Mercruiser 470 4cy. 224 series 190 HP..
The engine is new rebuilt, less then 2 hours on it. it was rebuilt do to bad oil pan......

have been having problem w/ my 4-bbl Rochester quadrajet carb.
it has all started 4~5 moths a go before the engine rebuilt, my carb has start flooding, after starting in less then 1 minutes you can see fuel gushing out of the accelerator pump & the carb was flooding, so we had the carbe rebuild.

same problem,
took the carbs back to the shop, he did some fine tuning, but the problem did not go away, we took the carb back to him 4 times, same problem...
he has adjust the float, still the same...

so i found a reputable carb places in CA and ordered a re manufactured carb , same problem.... :-(

now that i think i remember that we have replaced the fuel pump also at the same time, i just ca't remember if it was before or after the carb reaper.
The original pump looked like it was 86234A4, but the new pump is like it but not the same, the fuel in & fuel out connectors are facing to the back to the boat.. the old one was fuel in was facing the front of the boat fuel out was to the back of the boat, also the new pump is much shorter...

our boat mechanic told me that we have 6lbs pressure, was told that i should have 3.4lbs,..
the shop who sold me the pump is telling me that the pump is fine, and my carb pressure should be 3 to 7 Lbs...

Thanks to one other forum i have found out that the vent house of the pump should be connected to the carb, it was hanging all this time no flue the vent hose.


no w i'm lost :-( i don't know what to do :-(

can someone please help me
Moses

 

[BaileysBoat]

Re: Merc 470 & Rochester quadrajet problem: flooding

Have you got a good filter at the carb? Assuming the float level is ok needle and seat might be have picked up something from the fuel thats not letting it close.

Fuel presssure sounds ok to me but I'm a car guy.

 

[Bondo]

Re: Merc 470 & Rochester quadrajet problem: flooding

our boat mechanic told me that we have 6lbs pressure, was told that i should have 3.4lbs,..
the shop who sold me the pump is telling me that the pump is fine, and my carb pressure should be 3 to 7 Lbs...

Ayuh,... That ain't the Problem.... 6psi is Fine for a Carbed motor...

It's gotta be the Carb...

 

[JustJason]

Re: Merc 470 & Rochester quadrajet problem: flooding

if your sure it's comming out of the accelerator pump discharge ports check the ball and spring valve in the accelerator pump circuit. I bet its the wrong size balls or the balls are missing all together.


hehehe.... missing balls....

 

[CAPTKEV85]

Re: Merc 470 & Rochester quadrajet problem: flooding

when you bought the carb. Did you ever leave it upside down anywere. Cause if its was transportes through ups,fedex, or whatever. If it was thrown around and upsides down the needle could of fell out. happend to me.

 

[duduk]

Re: Merc 470 & Rochester quadrajet problem: flooding

HI



did a new test on it and the pump has 9lbs pressure
so took out the old pump from other side and installed on port it worked fine, no problem,s

i need 2 new fuel pumps

my old pump is made by Carter
any idea who might have them ??

Thanks MOses

 

[duduk]

Re: Merc 470 & Rochester quadrajet problem: flooding

when you bought the carb. Did you ever leave it upside down anywere. Cause if its was transportes through ups,fedex, or whatever. If it was thrown around and upsides down the needle could of fell out. happend to me.

UPS
i'll take it dawn to carb shop my self and have him exchange it, since i need a carb that has a vent hole for the hose from the pump

 

[duduk]

Re: Merc 470 & Rochester quadrajet problem: flooding

Thank you all



Moses

 

[bpmcl00]

Re: Merc 470 & Rochester quadrajet problem: flooding

i had the same problem on my 4 barrel.. the owner before me said it would flood everytime he ran it... He put a holly fuel regulator from the pump to the carb and i have never had the issue.. my carb is kinda whack though. i think that because of the regulator my acc. pump is not getting gas and is prob why my boat start after sitting for a couple days.

 

[duduk]

Re: Merc 470 & Rochester quadrajet problem: flooding

Hi
Thank you All




All of my problems have been solved, except one :-( the clear hose from the fuel pump, have no connection / nipple on the carb, can someone please post a picture to show place of the connection ?? i just don't have any place on the carb to connect


Moses

 

[chiefalen]

Re: Merc 470 & Rochester quadrajet problem: flooding

BECAUSE IT AIN'T A MARINE CARB. Not safe and that got to go back, with a note telling them you need a new carb for a boat.

So you got the wrong fuel pump cause no matter what anyone tells ya you need between 3.5 - 6 psi no more for a carbed motor or it will over power the float and needle.

 

[Don S]

Re: Merc 470 & Rochester quadrajet problem: flooding

BECAUSE IT AIN'T A MARINE CARB. Not safe and that got to go back, with a note telling them you need a new carb for a boat.

Not all QJets had fittings in them. So don't just assume it's automotive.

Moses:
If you are sure this is a marine carb, it may not have the fitting in it for the clear tube. The marine Qjets had different methods of fuel pump site tubes on OMC and Volve carbs which could be the same thing you have.
Can you post a picture of the carb area just above the fuel inlet tube into the carb?

 

[s1120]

Re: Merc 470 & Rochester quadrajet problem: flooding

Hmm... I have my 86 torn apart inside.. I have the 190hp also. I will check today where that hose goes...

 

[s1120]

Re: Merc 470 & Rochester quadrajet problem: flooding

Sorry fir the delay. I finly got out to the boat. On the engine side of the carb, there is a small hole tapped in the airhorn right under where the flame arrester mounts. There is a small brass fitting there, that the hose mounts to.