speedo not reading

[cem]

i found on saturday when we were out is that our speedo wasn't registering anything, i know it did as during the sea trial there is a registered speed recorded on the paperwork....from what i have read (which could be wrong) it is fed via a small hole in the leading edge of the stern drive??

is it a very small hole? what might block it? is there something inside to go wrong? or is it something at the other end of the cable (up at the dash) all the fittings at that end appear to be very solidly into the back of the gauge

any suggestions very welcome (one day i will have enough knowledge on this suff to help someone else out!!)

[jokaboat]

It's either a small hole which can get clogged by crud, in which case get a fine drill and rotate it by hand to clear the debris, or it's a pressure plate which transfers the pressure up a tube to the speedo. If the latter it might be that the tube has come loose at one end or t'other or the tube has a hole in ti somewhere or the tube has a kink.

The most likely reason is crud in the hole.

[betty boop]

if its an alpha gen 2, theres a small indent on the front facing edge lower leg , about 5mm in dia, usuall dripples water after the leg is dry- easile gets clogged with muck as JB says- if the drill dont clear it as with mine, reach up into the gap just above the lower leg, take off the push fit connector and give the hole a blow. but make sure your neighbours/kids/wife is watching they'll think ur a perv. worked for me blowing the muck out and the taste of colt salty steel

[Ed]

I found something interesting the other day which may be of interest to some.

Teleflex now do GPS speedos which look like normal gauges. The can connect to the nmea bus from a chart plotter or via a nmea gps receiver. They arn't that expensive too I thought.

[JORIDAPILOT]

It's either a small hole which can get clogged by crud, in which case get a fine drill and rotate it by hand to clear the debris, or it's a pressure plate which transfers the pressure up a tube to the speedo. If the latter it might be that the tube has come loose at one end or t'other or the tube has a hole in it somewhere or the tube has a kink.

Did you achieve reasonable speed when out by your self, if you have a pressure plate type then they don't register untill you are doing 15 - 20 mph. I don't ever look at the speedometer but rely on the speed readout on the chartplotter, this gives speed over the ground and the various harbourmasters cant argue with it if they think you are exceeding their limit.

[Ed]

Here we go have a look at these:

http://teleflexmarine.com/wp-content/up ... ometer.pdf

[JORIDAPILOT]

Here we go have a look at these:

http://teleflexmarine.com/wp-content/up ... ometer.pdf

Does any one make these reading knots for the more traditionally minded

[Ed]

hmm no idea I'm afraid.

[cem]

can anyone see a problem with using compressed air in a can to blow throught the speedo hole (from the joint 1/2 way up the leg and downwards of course!!)

[Rinker]

Hi Cem,
I had the same problem with mine. I disconected the tube where it attaches to the outdrive them got a piece of MIG welder wire and pushed it into the hole at the bottom end end and then the top end and cleared the obstruction. I finished the job off with a good blow through from an airline. Job Done speedo working.

[cem]

Hi Cem,
I had the same problem with mine. I disconected the tube where it attaches to the outdrive them got a piece of MIG welder wire and pushed it into the hole at the bottom end end and then the top end and cleared the obstruction. I finished the job off with a good blow through from an airline. Job Done speedo working.

i seperated it at the mid point of the leg then blew through it with an air duster... air coming through no problem still not working so i guess the problem is further up the line.... not to worry got the GPS plotter working so it shows us what we were really doing!!