EMPI DFEV Adjustment

[tartan18]

With my fuel fill up today I calculated that I am getting only 14 mpg. I don't have a lead foot so I suspect that my carburetor is not adjusted properly. I followed the directions regarding setting the idle mixture and idle speed. Are there other adjustments I need to check? For example in this picture there is an adjustment screw right behind the electric choke. Any ideas would be appreciated.



Yes, I do note that my fuel filter has captured a lot of grit -- I will replace the filter cartridge soon.

[So Cal Mark]

the screw behind the choke is the fast idle speed adjustment. Have you verified the choke is getting power and opens completely? Those carbs are not jetted on the rich side, normally they're perfect for an 1800 right out of the box

[manoa matt]

Is that blue braided brake hose attached to the carb and then to the manifold? I'm not sure if it makes a difference, but I would cap those off if not needed in stead of connecting them.

[tartan18]

The choke gets 12v and here is a picture of the carb after about a minute of the engine running. I note that there is a lot of black soot -- my EMPI 32/36 DFEV has only been installed for a few months. Is this normal?

[So Cal Mark]

how much blowby do you have coming through the crankcase breather hose? What do you have the timing set at?

[tartan18]

Starting with a cold engine there is no blowby through the breather. But once the engine has warmed up a bit it coughs once or twice before the engine starts. Timing is set at 12 btdc. I did remove the vacuum hose at Matt's suggestion. Both connections (to the carb and to the intake manifold) are now capped off.

[So Cal Mark]

I was asking about blowby, not start up. Deposits in the carb air horn are usually caused by blowby or reversion, neither of which are carb problems

[tartan18]

How do I tell if my engine is exhibiting blowby? I know that it means that gasses are leaking past the piston rings and getting into the crankcase but how do I "know" this is happening?

Thanks for the continuing help!

[DocGraphics]

Here's a complete trouble shooting guide off webercarbsdirect.com
It trouble shoots alot of different problems & last page diagrams all the hook up points on the DFEV & DGEV.

http://www.webercarbsdirect.com/v/vspfi ... 0Guide.pdf

[So Cal Mark]

you will see evidence of blowby through the crankcase breather hose

[tartan18]

From the look of the soot on my spark plugs it is clear that I have a blow-by problem. These plugs have less than 100 miles on them. Does this mean that my piston rings are bad or could it be a problem with my valves? I don't have a compression gauge to diagnose a ring problem so I am going to have a friend come by and check that out for me. I am also going to check the valve (tappet) clearances at the same time.

Any other ideas?

[digitech]

Doesn't look like blow-by to me, looks more like too rich.

[tartan18]

If the carb is set so it is too rich that would explain my lousy gas mileage (14 mpg). I've adjusted the idle mixture and idle speed according to the Weber instructions. What am I missing?

[124JOE]

they may have turned black during tunning
throw in a clean set to see if its still doing that before retunning

[tartan18]

Thanks Joe. I will do that tomorrow.