TR 2 - 4 Fuel Guage Senging Units

[Tinkerman]

I have four fuel sending units, three are OK but the fourth one I suspect, needs some adjusting, will tend to that later. My question to the BCF is the stamping on the sending unit. They are all Smiths units #FT 3331/02. Three are further stamped MM3 and one is stamped MM2. Any significance to the different MM numbers? The MM2 has a differently shaped body.

Thanks for your thoughts, Tinkerman

 

[Geo Hahn]

I suppose the key question is what resistance they have when in the full position... should be about 70 ohms I think.

 

[martx-5]

Yes, 70 ohms is the spec for full, but mine measures about 80 ohms when I give it full swing out of the tank. It probably never gets quite that high when the tank is full, hence the 70 ohm spec.

Where is that MM number? I didn't see it on mine, but then again the top of mine has 45 years of patina on it. I did see the FT 3331/02 number and 12V on it.

 

[Tinkerman]

Hi Art:
The MM number is to the right of the FT3331 number and perpendicular to the FT3331. Might not mean a thing but I was just curious and yes mine measures 80 ohms in the full position, all of them do. I was planning on cleaning them all with contact cleaner. Make sense?

Tinkerman