rochester carb flooding engine?

talies13

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I think my carb is flooding my engine. It runs great when I first start it after I shut it down for a while it won'tstartagain. Unless I let it sit for a few hours. I have a large fuel filter attached to the fuel line. It is a 4 brl Rochester quadrojet on a 19789 5.8 omc any thoughts?
 

RogersJetboat454

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Re: rochester carb flooding engine?

Did you ever follow up on checking for spark when the engine dies out?

Is the choke opening up when the engine warms up? Have you pulled the spark plugs out to check if they are either black or wet with fuel?
 

talies13

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Re: rochester carb flooding engine?

Sorry I didn't repost . Yes it is geting spark and plugs look real good now no soot any more. I went to a hotter plug and thought all was well. After running it for about 20 min I shut it down . After about 15 min tried to start again and no luck. Batery readers 12.56 v I checked carb and opened the small barrels and looked down into the engine and could see gas pooled in the bottom of the engine.
 

Don S

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Re: rochester carb flooding engine?

Opening the throttle to look into the carb squirts fuel in the engine. If the plugs don't show flooded, that's not your problem.
Do you open the throttle to about a quarter when starting warm? If not, try it.
 

talies13

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Re: rochester carb flooding engine?

Ok thanks. I just tried that and I was able to get it started after that I removed the fuel hose and les it burn the extra fuel out of engine . Then replaced hose and was able to start it in neutral. I set idle to about 500 rpms for now. What could cause the execs fuel in the bottom of carb or is it supposed to be there.
 

RogersJetboat454

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Re: rochester carb flooding engine?

What could cause the execs fuel in the bottom of carb or is it supposed to be there.

When you opened up the throttle plates to take a peak, the accelerator pump squirted the extra fuel into the intake. It's supposed to do this to en-richen the fuel mixture for both cold starting, and heavy acceleration.

BTW, 500 RPM may be a bit low, bring it up to around 600. I assume your idle mixture has been properly set, correct?
 

talies13

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Re: rochester carb flooding engine?

i personally have not messed with the idle mixture since i bought the carb. it was supposed to be tuned when i got it. i tried looking for the screws but the distributor is going to make it hard to get to them.
is there supposed to be this much fuel in the bottom?
 

keith2k455

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Re: rochester carb flooding engine?

If your carb is truly flooding the engine I would check float level.

To me it seems like it's just your normal carbed engine ... They can all take a little coaxing ... Almost like a black art
 

Don S

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Re: rochester carb flooding engine?

i personally have not messed with the idle mixture since i bought the carb. it was supposed to be tuned when i got it.

They can't do that for the idle mixture, even the manuals only give you preliminary settings for the mixture.
The carb manufacturer has no idea what vacuum to adjust it to, or what your tunup settings and compression are like.
Part of installing a new carb is adjusting the idle speed and the idle mixture.
PS: you should be idling around 650-700 in gear.
 

talies13

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Re: rochester carb flooding engine?

IMAG1096.jpg
this is the set up . the in line fuel filter wouldnt have anything to do with this would it?
 

Reinell-BRXL-191

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Re: rochester carb flooding engine?

I am going to bet there is a leak in the bowl gasket.. I would check the tightness of the screws that hold the bottom plate to the carb, and the top plate as well.. that is way too much gas sitting in there to be explained away with accelerator pump squirt.. The carb looks new, so, I would doubt a float level problem, because that would cause problems when running... I will bet the main well is leaking down after shut off - Rochesters with dry gaskets are notorious for it - I always seat my gaskets after soaking them in gas first

Also, could be something as small as a check ball that was not put in during assembly... I would take it apart and make sure it is all there, and re-seat all the gaskets
 

RogersJetboat454

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Re: rochester carb flooding engine?

View attachment 183279
this is the set up . the in line fuel filter wouldnt have anything to do with this would it?

Is the in-line filter causing it? I doubt it.
But a word of caution, I personally wouldn't be using a plastic filter in the engine compartment of a boat. If it ever got hot enough to melt the plastic, I'm sure you could guess what may happen. Would be better to install a fuel/water separator with spin on cartridges (look like an oil filter).
 

talies13

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Re: rochester carb flooding engine?

Thanks for the info. I will remove the inline filter I don't trust it either. Allso I will go through and tighten all bolts on carb. The gaskets do allways look wet . I will try that and see what's up.
 

talies13

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Re: rochester carb flooding engine?

quick update .i changed the base gasket to the thicker 1/4 inch gasket and tightened everything down yesterday started it first thing yesterday morning and started perfectly. ran for about 20 min runs smooth shut it down waited 15 min and no start. didnt get a chanch to do anything else so went out this morning on a cold 30 degrees and turned the key and it starts instantly, and runs smooth as silk i let it run for 20 to thirty min checking oil and watching the carb and all is normal. so i shut it off and wait......... try to start and it wont! however this time i take the crank case hoses off of carb and try to start again . no luck i try it at 1/4 throttle and the hose pucks out a yellow foamy frothy substance!!!??? now i have no idea what this is. a few months ago i did overfill with oil. i removed all of the old oil a couple of weeks ago and replaced it with 5quarts oil and one quart lucas oil additave oil looks perfectly clean at all times. what is this foam???IMAG1108.jpgIMAG1107.jpgIMAG1104.jpg
 

RogersJetboat454

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Re: rochester carb flooding engine?

so went out this morning on a cold 30 degrees

i try it at 1/4 throttle and the hose pucks out a yellow foamy frothy substance!!!??? now i have no idea what this is. a few months ago i did overfill with oil. i removed all of the old oil a couple of weeks ago and replaced it with 5quarts oil and one quart lucas oil additave oil looks perfectly clean at all times. what is this foam???

30?? As in 30? Fahrenheit???
If that's correct, have you been draining the water out of the block when it's been getting that cold?

If you haven't, your running problems may now be an afterthought (cracked block)...

That yellow stuff being puked out looks like oil contaminated with water. Is the oil level up?
 

talies13

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Re: rochester carb flooding engine?

No I drain it ever day block and manifolds. Oil level is still the same. Oil pressure is perfect.
 

RogersJetboat454

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Re: rochester carb flooding engine?

No I drain it ever day block and manifolds. Oil level is still the same. Oil pressure is perfect.

In that case, what you're seeing is most likely what I said, only it's just normal condensation (from the large temp swings of running it up to temp, and cooling it off). If you can get the engine to run long enough, it will most likely burn all that off.
 

talies13

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Re: rochester carb flooding engine?

Thanks!,I was just reading about that they said the same thing about high viscosity oils tend to do that untill i burn it all off. I think I will drain the oil in the morning and inspect it an d add new oil minuse the Lucas additive.
 

RogersJetboat454

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Re: rochester carb flooding engine?

Thanks!,I was just reading about that they said the same thing about high viscosity oils tend to do that untill i burn it all off. I think I will drain the oil in the morning and inspect it an d add new oil minuse the Lucas additive.

IMHO, viscosity doesn't matter much. It's the short running with large temperature changes that make for the perfect conditions to produce condensation.

Pull the oil cap off an old Lady's car engine, and I guarentee you're going to see Baileys Irish Cream on the bottom of the cap. A car owned by a highway commuter that's on the road for more than 20 minutes at a time will have none of that.
 

talies13

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Re: rochester carb flooding engine?

update on foam. no more foam ran it for a good hour and no problems with foam . however let it sit for abut 30 min and no start again . however did notice that there was very little fuel in the in line fuel filter so i added more fuel to boat and was only able to get it started with the throttle all the way open . but still no fuel in filter. looks like fuel was comeing into carb through overflow hose... is my fuel pump dead when this happens?
 
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