Horrible mpg horrible gas smell stumped.

[hoffa65]

If its starting hard when hot and you smell gas its most likely flooded from gas pouring down the carb when sitting hot.
you replaced the gas cap, it many not be venting properly and pressure is building in system and forcing fuel out the carb down the intake. after sitting hot open gas cap and check for a hissing sound.
your oil is most likely diluted with fuel now, pull dip stick and smell for raw gas smell.

 

[Stupidquestionspro]

Thanks I’ll have to check that and definitely could be bum gas. Once I figured out how low my compression is to help my depression over it I’ve been using shell 87.

I’ll have to check the venting situation. I’m not sure the proper venting set up so I’ll have to take a look.

This is very annoying for sure.


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[85442/86buick]

has mentioned in this or another one of your other threads.................drop the tank and replace the 3 ( ? ) small sections of rubber hose that connect the tank to the hard lines.
and check out the canister in the front passenger side corncer............it's pretty simple ...thinking fish tank charcoal & a filter across the bottom ( from rock auto )

And your in Florida ? with the summer heat the 87 Octane gas............is trash.

I have been wrong before & I will be wrong again !

 

[83StreetMachine]

Check for vacuum leaks as well. At 1.5 turns out it should run pretty good


Also, do you have a know good fuel pressure gauge? Not just one of those tiny liquid filled ones?

I know you said you checked but Double check your fuel pressure. I'd put it no more than 6 psi

 

[hoffa65]

Thanks I’ll have to check that and definitely could be bum gas. Once I figured out how low my compression is to help my depression over it I’ve been using shell 87.

I’ll have to check the venting situation. I’m not sure the proper venting set up so I’ll have to take a look.

This is very annoying for sure.


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not burned gas raw gas.
as the liquid gas flows down the intake it will enter any clinder that has an opened intake valve, it will then make its way pasted the rings washing any oil on the rings off as it passes by to finally get to the oil pan

 

[Stupidquestionspro]

has mentioned in this or another one of your other threads.................drop the tank and replace the 3 ( ? ) small sections of rubber hose that connect the tank to the hard lines.
and check out the canister in the front passenger side corncer............it's pretty simple ...thinking fish tank charcoal & a filter across the bottom ( from rock auto )

And your in Florida ? with the summer heat the 87 Octane gas............is trash.

I have been wrong before & I will be wrong again !

I intend to do just that just have to find available time. I do have a charcoal canister which is currently hooked to the old return line and the second port is plugged because when I ran with it unplugged it didn’t seem to improve the situation any it seemed to make the fuel smell even worse.

Yea my next tank I’ll do 89 because 91 is premium so I’m hoping I don’t have to go that far considering the price difference


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[Stupidquestionspro]

Check for vacuum leaks as well. At 1.5 turns out it should run pretty good


Also, do you have a know good fuel pressure gauge? Not just one of those tiny liquid filled ones?

I know you said you checked but Double check your fuel pressure. I'd put it no more than 6 psi

No vacuum leaks and yes I have a vacuum/fuel gauge just have to have the time to disconnect the fuel line and check it again. How long do I crank the motor to ensure the proper reading?


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[Stupidquestionspro]

So finished the tank only got 8.28 mpg this time filled up with shell 89 instead of 87.

Gonna start doing some work soon so what’s the difference between a 2 or 3 port mechanical fuel pump?????

Also I am thinking about getting a 1/4 inch phenolic space will that actually keep my carb cooler?

Also the 4 hole carb spacer I have a dual plane intake and a summit carb that is essentially a Holley 4010 will the 4 hole cost me performance I know an open isn’t recommended with a dual plane would rather not buy the wrong parts

Also what is the best fuel line material and routing to avoid from heating my fuel?

Thanks for the help.


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[fleming442]

3 port has a return line which requires a 3 port sending unit in the tank. It is a better design because the heated fuel can return to the tank to cool down. You would have to run the return line, though.

 

[Stupidquestionspro]

Well the engine was originally a 3.8 I have a supply hard line and a second hard line already connected to the tank but for now connected to the charcoal canister so would that have been a return line or did they run a second hard line for a vent?


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