Mechanical fuel pump, to much psi??

[DBK81]

Running a Edelbrock 750 have a raw fuel smell in my garage, as well truck starts harder than it should when warm. Wondering if it's possible that my mechanical fuel pump is pushing to much psi? Changed my oil this spring and it smelled of fuel as well which is my biggest concern. Think a fuel pressure regulator is nessasary?

[Rod Run]

Raw fuel smell should have nothing to do with your pump, nor should your hard starting.

Hard starting could be many things but two big ones are usually starter heatsoak or timing being off

[DBK81]

It's not heat soak. When cold, it starts like a dream, and if I shut off and start back up warm within about 30 seconds it start perfect. Reason I ask about psi is I know Edelbrock carbs are notorious for pushing fuel into intake if anything over 7 psi but like 5-6psi best.

[DBK81]

Originally Posted by Rod Run

Raw fuel smell should have nothing to do with your pump, nor should your hard starting.

Hard starting could be many things but two big ones are usually starter heatsoak or timing being off

I'll check the timing and report back.

[Shady Rascal]

Hard start when warm problems on Edelbrock carbs are solved by putting a heat insulating spacer between the carb and manifold. It doesn't need to be anything exotic. A cheap thin phenolic spacer will do the trick. The reason for this is that the fuel bowl on the Edelbrock carb are centralized and the engine heat boils the fuel off when you shut the engine down. Not a problem on Holley type of carbs since their fuel bowls hang off the ends of the carb body and are not directly over that hot manifold. This is the same reason that original Quadrajet carbs use that thick base gasket that they do.

[hugger6933]

I'd check the pressure on that pump. If it were a high performance type pump is is very possible that it needs to be regulated. Or it could be the pump itself allowing the fuel to get into the crankcase. Most likely it is [pump] is overtaking the N/S

[Mike C]

I run a Carter Race pump on the Camaro at 8 psi with no problems. I would be concerned your pump is bad though with a diaphragm leak into the crankcase. They don't cost much so I would be replacing it before trying to troubleshoot anything else.

[geezer#99]

Originally Posted by DBK81

It's not heat soak. When cold, it starts like a dream, and if I shut off and start back up warm within about 30 seconds it start perfect. Reason I ask about psi is I know Edelbrock carbs are notorious for pushing fuel into intake if anything over 7 psi but like 5-6psi best.

Eddy carbs don't like more than 5 psi.
Put a regulator on it.

[DBK81]

It does have a high Preformance mechanical pump. Going to test the psi today. Will report back.

[cdowns]

edelbrrock carbs do better when installed with a phenolic spacer is used that prevents fuel from boiling out when you turn it off

[DBK81]

I think I'd if it was just the hard warm start I'd be more apt to look at the spacer, but the fact there is such a strong raw gas smell as well as oil smelling of gas in the past I really think this is a over fueling issue, if after I handle the pressure and timing I still have the hard warm start issues I will do the spacer.

Sure appreciate the reply's and input guys.

[Myoldtruck]

I just pulled my edelbrock off and benched it permanently for the same reasons. My truck came with it already when i bought the truck. I had to keep monkey around with a regulator, then still flooding at idle. I bought a rebuild kit, with new floats and needle/seat,which is what needs to be done.

It was easier to send out the original carb to get rebuilt. I wanted better gas mileage and reliability.

[DBK81]

Ok, suspicions confirmed. Tested fuel pressure and it is running at 7.5psi, going to buy a fuel regulator and get it dialed down to 5 psi, will report if that solves my problems, I will say it has been exceptionally hard on fuel, thinking this will help with that issue as well.

[AnotherWs6]

Or buy a self regulated Edelbrock fuel pump. I am on my third install of a an Edelbrock carb and pump at the same time. First two ran awesome out of the box, no issues at all after years.

[cleszkie]

Don't forget to check your oil for fuel smell again. Change it if you get the smell, you don't want to wipe out your bearings.

[AnotherWs6]

Not to hijack, but fuel in the oil is an issue I have never had before, but I think I have now. Am I getting this straight - if the fuel pump diaphram is damaged fuel can leak into the crank case? Can fuel get in there if the carb is getting too much fuel or running way too rich?

My oil felt a bit thin when I bought the truck and brought it home. I changed it and out synthetic 10-30 in it and it looks a bit thin now too. With a total of maybe 20 miles since the change. And it had the faint odor of gas. I took the old Holley and factory-looking fuel pump off last weekend. Got the new pump installed, hoping to get the new carb setup this weekend. I'm doing this for drive-ability reasons but am also hoping to fix this gas/oil problem if it's not just my imagination.

[cleszkie]

Originally Posted by AnotherWs6

Not to hijack, but fuel in the oil is an issue I have never had before, but I think I have now. Am I getting this straight - if the fuel pump diaphram is damaged fuel can leak into the crank case? Can fuel get in there if the carb is getting too much fuel or running way too rich?

Yes - bad pump can allow gas into crankcase.

Yes - gas can potentially make it past your rings if there is a lot of it, and your rings are worn. But I believe the gas would have to sit on the rings for a period of time. Excess gas while running would just get blown out the exhaust valve.

[Jrainman]

I think you may be on the right track , your PSI is a little on the high side , but I would also check :

Check floats for leaks

check float level , take the top half of the carb off bench it upside down, take 7/16 drill bit to check float height roll bit under the first 1/2'' of floats ,if gap is more then 7/16'' adjust by bending float arms

Check float needle and seat make sure needle is sealing in seat ,move floats open and close, use 5-6 psi air pressure if blow exists adjust or replace needle and seat.

these would be other considerations when the smell of raw fuel is present along with to high fuel pressure causing the needle and seat to have blow by.

[DBK81]

Installed fuel pressure regulator and smell and warm staring issues are gone. Success!