Leaded Gasoline???

[petersen_1955]

I just bought a '75 Cobalt with a Ford 351 about a month ago. I'm on my second tank of gas and it is running REAL rough, with smoke (gas smell) coming out of the exhaust until it warms up.<br /><br />I just read on top of the engine that you need to run at least 88 octane (I put midgrade in it the second tankful). It also says LEADED gas and not unleaded. <br /><br />Do I need to add a lead additive? Is this why it is smoking?

 

[8AteEight]

Re: Leaded Gasoline???

I think its more the choke setting on the carb. You do say it gets better after its warm right?? I think if you set the choke back about 2-3 clicks, itd get better.<br /><br />This is just my opinion though.<br /><br />BTW, that lil boat with a 351?? Dang, she must have a lil scootage to her.......

 

[qaztwo]

Re: Leaded Gasoline???

You can buy a lead substitute that you add at fill up. Only thing that lead does that no lead does is increase your valves life. Newer engines have hardened valve seats yours does not. I would also look at the carb, or timing.

 

[petersen_1955]

Re: Leaded Gasoline???

It's 64 degrees out. I went out and adjusted the choke (two clicks clockwise). It bumped up the idle to 900 rpm (700 was normal when it was 80 degrees out). I took it for a spin and it seems to idle fairly well and no smoke. When I gave her some gas it felt like it was hesitating a bit. It ran fine before I filled it up last week. I put a couple of bottles of Heet in it a couple of days ago in case there was any water in the system. Any thoughts?