Fuel Injection - 1962

[Don B.]

I have a 62 Fuelie. I found that I had fuel seeping from the top/side of my Fuel Meter Cover. Upon disassembly I discovered the wrong gasket had been installed so I bought a new rebuild gasket kit and replaced the incorrect gasket. I also inspected and checked the float and bowl for any debris - checked the float level and reassembled. After startup and warm up to normal operating temperature then subsequent shutdown I found I had a small amount fuel coming out of the top vent cover at the rear of the fuel meter.

After further investigation I noted that when the engine was idling, fuel in the Fuel Meter body covered the float by about 1/2" and the fuel came up to about 1/2" of the Fuel Meter Cover. Is this normal for a float to be completely covered in a FI unit? The float moves normally and all else is normal.

There are no leaks in the float and it easy to "adjust" the float to a lower level. Is this the fix to my "venting" issue?

[Jim L.]

Re: Fuel Injection - 1962

Don, no what you are describing is not normal. The float, when everything is in good condition should be mostly above the level of the fuel in the bowl. If you are sure the float isn't filling with fuel due to a leak, then a possibility is the float is rubbing and slightly hanging up on the inboard interior wall of the fuel meter.

As designed and manufactured, there is very little space between the float and that bowl wall. As the pivot arm wears, the float can contact the wall and the friction is enough to prevent the float from rising enough to close the needle/seat. If that's the situation with your float, you are lucky. I've seen cases in which the float hung up so badly the whole bowl filled to overflowing.

When I rebuild an FI unit, I replace the float pivot arm and I shift the float about 1/16" outboard to positively prevent the hang up condition from ever happening.

Your FI unit may have a completely different problem, but it doesn't hurt to be aware of this possibility.

Jim

[John D.]

Re: Fuel Injection - 1962

Don, I assume you replaced the needle and seat.
Did you set the float drop as well as float level. Jim Lockwood mentioned about the float rubbing against the side of the fuel bowl.
Is there much wear in the float where the float pin goes thru? What about the fuel meter cover. Much wear such as oblonged holes on the cover.(for float pin)
What did you set the float drop at. ST 12 manual says 2-9/32 for the level and 2-27/32 for the drop. Some thing is not critical but since RP used this spec I follow it. (almost)
Here's one I learned many years ago from Gail Parsons. He called me one day and said quit telling people that the engine fuel pump should put out about 3-1/2 to 5". He said that 5" is too much.
Too much engine fuel pump pressure could be overpowering the needle and seat and letting too much fuel in your bowl.
I also am wondering what kind of ability the fellow before you had Don when he put a wrong gasket on the fuel bowl to fuel meter cover. I am thinking that gasket must have been a '57 gasket???
Basically a fuel injection float set up is identical in theory to a carb setup.
If you have issues my contact info is in the Restorer on page 2
. Call me as it's hard typing with two fingers to cover all the details. Thanks, John
I would not drive the car until you resolve this issues.

[Don B.]

Re: Fuel Injection - 1962

Thanks Jim. I will take it apart and recheck all the clearances with that in mind.

Don

[Don B.]

Re: Fuel Injection - 1962

Hi John,

I am going to take the fuel meter top off again and recheck all the float related components. I had the entire FI unit rebuilt about 2 years ago but I do not know if all the internals were replaced with new parts. I did remove the needle and seat and they appeared to be in good condition. I have had no reason to open it up as it has run fine. You are correct about the gasket, probably for a 57.

I will call you about the particulars and i may need some parts.

Thanks for the information.

Don

[Jim L.]

Re: Fuel Injection - 1962

Thanks Jim. I will take it apart and recheck all the clearances with that in mind.

Don

Don, what you want to look for is a shiny area on the float, indicating it's been in contact with the bowl wall. If present, this will be at the forward end of the float, inboard side. If the float has been rubbing, there will also be a corresponding mark on the bowl wall. You can see an example in the attached picture.

Jim

[Don B.]

Re: Fuel Injection - 1962

That picture helps a lot! I wouldn't have thought that is where it would rub the side.

Don

[John D.]

Re: Fuel Injection - 1962

Very nice photos Don. Luckily it wasn't old JD here that did that screw up.

[Don B.]

Re: Fuel Injection - 1962

I thoroughly examined the unit and found no rubbing or elongation of the float pin openings and no trash in the bowl. I then replaced the needle and seat, calibrated the the float, and put on a new fuel filter. I tested the float level by cold cranking the engine, then started it up. The float now works properly and the fuel level is well below the top of the float. The needle and seat must have degraded over time.

Thanks for all your help guys,

Don

[John D.]

Re: Fuel Injection - 1962

Good job Don. The viton needle and seats will hold more fuel pump pressure that the original steel ones. I learned that info years ago from Brian Futo and also Gail Parsons. John D

[Ian G.]

Re: Fuel Injection - 1962

John, in other words the needle (shaped like a bullet) with the rubber tip is better vs the original metal tipped one?

[G B.]

Re: Fuel Injection - 1962

The nylon-tipped needle/seat valves are from carburetor applications. They have a much smaller opening than original all-metal FI needle/seat valves. The smaller seat area means they can withstand more inlet pressure, but they don't pass as much gasoline at full throttle. The nylon tips also wear out. I've yet to encounter an original FI needle/seat valve with enough wear to keep it from sealing.

[Ian G.]

[Ian G.]

Re: Fuel Injection - 1962

You piqued my interest quite a bit Jerry... I decided to measure them with my calipers. The nylon tipped orifice one is .125, while my original (I assume original) is .155. What benefit would there be to "withstanding more pressure"? Smoother acceleration, just less of it? Less chance of some kind of flooding in certain circumstances?

[G B.]

Re: Fuel Injection - 1962

Long story short: I don't see a benefit of using the smaller inlet orifice. If an engine fuel pump is putting out so much pressure it overcomes the original FI needle/seat valve and stock float, the fuel pump needs to be fixed. The answer isn't to replace the needle/seat valve.