Re: Speedo's and gas engines...Help !!
Two things I have done that seem to have alleviated some of the problems are:
Something similar to mentioned above but a little simpler. Take whatever excess wire you have on the speedo wire and fold it back on itself as shown in the picture. It helps cancel out some of the EMI.
The other thing I have done is use a shielded plug wire, basically standard automotive wire and boot.
Seems to have solved the problem.