1957 356 JPS replica

Good to hear. I am also the second owner.Mine has 2000 miles. Running rich fouled plugs. Adjusted carbs,changed plugs running great.

Paul ISAAC

@Phisaac posted:

Good to hear. I am also the second owner.Mine has 2000 miles. Running rich fouled plugs. Adjusted carbs,changed plugs running great.

Paul ISAAC

Paul,

If you want to reply to a specific comment move your cursor to the "gear" icon on the lower right part of the comment. Click on the gear icon and click on "Reply with Quote". That will include the comment that you are replying to to make it easier to follow the conversation.

Thanks.


Paul ISAAC

Thank you

Paul ISAAC

Thanks for sharing. Luckily I am the second owner. Just a few adjustments for me to overcome. The car is great fun. Still working on carb adjustment. Running very rich. Obvious in exhaust smeii and color. Spark plugs black when pulled and changed. Have you had similar problems with fuel mixture?

Paul Isaac
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> On Dec 4, 2020, at 11:32 AM, SpeedsterOwners.com <alerts@crowdstack.com> wrote:
>
> 

@Phisaac posted:

Thanks for sharing. Luckily I am the second owner. Just a few adjustments for me to overcome. The car is great fun. Still working on carb adjustment. Running very rich. Obvious in exhaust smeii and color. Spark plugs black when pulled and changed. Have you had similar problems with fuel mixture?

Paul Isaac
Sent from my iPad

> On Dec 4, 2020, at 11:32 AM, SpeedsterOwners.com <alerts@crowdstack.com> wrote:
>
>

Thinks for tip Robert

Got it

@Phisaac posted:

Thanks for sharing. Luckily I am the second owner. Just a few adjustments for me to overcome. The car is great fun. Still working on carb adjustment. Running very rich. Obvious in exhaust smeii and color. Spark plugs black when pulled and changed. Have you had similar problems with fuel mixture?

Paul Isaac
Sent from my iPad

> On Dec 4, 2020, at 11:32 AM, SpeedsterOwners.com <alerts@crowdstack.com> wrote:
>
>

Are you running a mechanical fuel pump or an electric fuel pump? I don't know if you mentioned it yet but what type of carburetors are you running; Dellortos, Webers, Solex? Fuel pressure has always been a source of running rich. Or incorrect float bowl adjustments etc. I'm in no way a carb guy but the rest of the group will need to know the answers to those questions so they can help you.

Yeah, I agree with Robert - In order to run that rich either (1) the jets are really screwed up (highly doubtful) or (2) the fuel pressure is too high (very possible) and pushing too much fuel past the float valves.  Neither of these can be fixed by playing with the mixture screws.  A third possibility is some crud keeping the float valves open but that should probably only affect one side of the engine at a time - if all your plugs are satin black then revert to idea (2.)

Also, as Robert mentioned, it is important that we know the type of fuel pump (electric or mechanical) and the type of carburetor (make and model) as different carbs require different fuel pressures and yours sounds like the pressure is too high.

If you don’t know what or where to look for that info, just ask and we’ll guide you.

A half or 3/4 turn too rich on a Weber idle volume screw can indeed result in BLACK plugs, sooty exhaust, and acrid unburned-fuel smell in the cabin.

I started with 60 idle jets, but ended up with 57.5 a few years later. I got it pretty good and NOT too rich with the 60s, and with no stinky fumes.

I know this because I didn't know how to properly adjust the carbs when I first got my car. Fuel pressure was exactly 3 psi and float valves were in perfect condition and float height was spot-on.

@Robert M posted:

Are you running a mechanical fuel pump or an electric fuel pump? I don't know if you mentioned it yet but what type of carburetors are you running; Dellortos, Webers, Solex? Fuel pressure has always been a source of running rich. Or incorrect float bowl adjustments etc. I'm in no way a carb guy but the rest of the group will need to know the answers to those questions so they can help you.

Mechanical fuel pump. Empire HMPX carbs with 55 idle jets. I have synced both carbs but only one on each carb? Not sure why! I will sync all four. Timing I’d set at 7.5 per Gervae Engines. New plugs made a big difference for the better.

I do appreciate everyone’s guidance

Paul

@DannyP posted:

A half or 3/4 turn too rich on a Weber idle volume screw can indeed result in BLACK plugs, sooty exhaust, and acrid unburned-fuel smell in the cabin.

I started with 60 idle jets, but ended up with 57.5 a few years later. I got it pretty good and NOT too rich with the 60s, and with no stinky fumes.

I know this because I didn't know how to properly adjust the carbs when I first got my car. Fuel pressure was exactly 3 psi and float valves were in perfect condition and float height was spot-on.

My idle jets are 55’s. Plugs helped a lot. No more carb popping. Will continue to work on carb adjustments. Thank you for your input.

@Phisaac posted:

My idle jets are 55’s. Plugs helped a lot. No more carb popping. Will continue to work on carb adjustments. Thank you for your input.

Definitely measure the actual fuel pressure output as well. If there's too much pressure the fuel will push past the fuel control system as Gordon said. That would probably be the next thing to do.

@Phisaac just saw your profile pic. Beautiful speedster. Grün Gruppe approved!

Thank you

Paul ISAAC