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Yamaha 140 V4

T

TTURTO

New member
Hi all,
recently bought a 140 v4(early blue), not sure of a year? Not charging battery & runs slow(38 mph on 19ft Crusader speedboat), but starts great. Also runs a little hotter on right bank. Think it's the stator, how do i check please? can't find anyone in the UK to rewind it?🙄🙏
 
What are the markings on the carburetors and CDI assembly?

Does 1989 sound about right as to the model year?
 
Within the stator there are several components. The one that produces electricity to charge a battery is known as the lighting coil. There should be two green wires from the lighting coil that provide electricity to the rectifier/regulator. The R/R provides electricity to the battery.

Test the output from the R/R for DC voltage. But first to check to see if there is a fuse in the loop and that the fuse is in good working order. I would expect you to see 13.5 volts or so from the R/R. With the motor at a fast idle.

If the voltage from the R/R is low then test the lighting coil outputs to the R/R. The peak AC voltage from the lighting coil with the motor running at 1500 RPM should be above 35 volts.
 
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