Fuel sender units

Post by **Dizzi141** » Wed Jul 20, 2005 7:57 pm

Well, Snowberry is legal, we finally got her taxed but HAVE to sort out her fuel guage problem. It gets embarrasssing for my Dad to keep having to call me and Lily to rescue him!
She was standing for 20ish years with a third full tank and thats all the guage will read now. Dad's tested the circuit and it's definitely the sender units that's dodgy. So, do we have to replace the sender unit or are they repairable? Dad said something about whether rheostats were accessible or not?
Thanks guys, Lily's still poorly as those at the national knew but Chris has got her engine out and is now puzzling over the engine to gearbox seal!

Post by **Willie** » Thu Jul 21, 2005 7:47 am

You would be very lucky if there was anything repairable inside
the sender unit, if the winding which gets wiped by the moving
arm has broken that is it! If you remove the lead from the sender
and touch it to a good chassis point the gauge should read full.
If it does then touch the same lead on to the petrol tank where it
should again read full. If it doesn't then the petrol tank is not a good
connection to the chassis. If it is proved to be the sender then
remember that you MUST use the one which matches the speedo.
i.e. a 948 sender unit will NOT work on a 1098 speedo and vica versa.

Post by **Vernon** » Thu Jul 21, 2005 8:16 am

a 948 sender unit will NOT work on a 1098 speedo and vica versa

That's right. I had one that showed I had more fuel the more I drove. If only it was true!

Post by **simmitc** » Thu Jul 21, 2005 12:44 pm

You MIGHT be able to use a piece of emery cloth to lightly clean the coil and the moving contact on the sneder unit. You MIGHT be able to free the moving arm if that's rusted in place. Then again pigs MIGHT fly. Swallow the pride, open the wallet, and get a new sender unit. Usual rules with petrol and testing things - be very careful, you don't want a spark over the top of the tank when the sender unit is out !

Post by **Dizzi141** » Wed Jul 27, 2005 7:16 pm

Shall pass that on to Dad, I think the idea was keep as much original as possible. Thanks folk

Post by **rayofleamington** » Thu Jul 28, 2005 6:03 pm

Chris has got her engine out and is now puzzling over the engine to gearbox seal!

There isn't one.
It's just an archimedes screw thingy which (normally) works ok until the engine is well worn or until the crank grinding people take the top off it.