Buy a dash mount for your hand held GPS (if you have one; if you don't buy
one) and then you'll have an accurate speedo.

Other than that, you could try changing the pitot tube (the plastic prong
shaped thing on the transom that connects by a tube to the speedo) and the
tubing going up to the gauge. It might be partially plugged. Also, a new
speedo, itself, is not all that expensive, and is easy to install, assuming
you can find a dial style that meets your needs. But, typical boat speedos
are notoriously inaccurate. It sounds like yours is more than 20 percent
off, which is kind of bad, but in my limited experience, that's not all that
surprising or super unusual.

Thus, my GPS suggestion is really made seriously. Once someone clued me
into that, I've never used a regular boat speedo. I had a handheld GPS and
it cost me about $30 to buy the bracket and power converter. It's as
accurate as you can get plus gives you all sorts of other features (the only
one I use is actual distance traveled, but I wish I could integrate it into
a fuel flow meter like some can).

Good luck.

Grissy.


"Kirk Davison" wrote in message
news:kO5cc.190432$po.1008776@attbi_s52...
Is there an easy way to adjust a speedometer on a 1982 Bayliner 1950
Capri,
It shows my top speed at 35 but a radar gun is showing 42. I have a 125
Volvo IO. This is a putt around the lake boat and being an old boat there
are a lot of things I would rather put money into than this but if there
is
an easy adjustment that would be great.
Kirk