Speed gauge

[Jeepman]

I run a 2005 60HP Mercury tiller which has a clear plastic tube running from the lower unit to the dash speed gauge.

The speed gauge is not working now.

Rather than taking the system apart "blindly," I'd like some advice as where to start. Has anyone had such a problem and can suggest where I start; that is, starting with the most common fix to the least common.

Jeepman

[yarcraft91]

I seem to recall a small hole on the leading edge of the lower unit that is the pickup for the speedometer port on my 2006 50 Merc 4-stroke. That could be plugged and would cause the speedo to stop reading. Probe with small steel needle (toothpick a bad idea, if it happens to break off inside port...)

I don't bother with that speedometer signal. GPS is more accurate at any speed.

[Jeepman]

Thanks. I'll be checking out that hole.

I too use the GPS for SOG which is most accurate, but I do like to think that I have everything working.

Thanks again.

Jeepman

[REW]

Jeepman,
Remove the speed o tubing from the motor. Use a bicycle pump and a sport ball needle to put a small amount of pressure on the speed - 0 very gently. Have some one keep an eye on the speed o needle. The needle should move off of 0 with a small amount of pressure on the line.

DO NOT use an air compressor to test the gauge - It is too easy to destroy the speed O gauge.

If this checks out - then find the tiny hole on the front side of the center of the engines lower unit and insure that it is free of weeds or sand. you may need to use a needle pin, or similar small stiff item. Also, the burred wires that are used to clean gas welding nozzles do an excellent job in clearing this small hole. Then, use the same bicycle pump and needle to blow back through the engine outlet where the tube connects and insure that air is coming out the front of the little hole on the front of the engines lower unit.

REW

[Jeepman]

Yarcraft and REW,

Thanks for the advice.

I found the tiny hole on the front edge of my lower unit. And using a tiny, tiny screw driver, I picked wood slivers out of the hole-- they were really packed in. Then, I remembered hitting and going over a log on the river last fall...the wood wedged into the hole.

Thanks for taking time to provide advice!

Jeepman

[yarcraft91]

Originally Posted by Jeepman

Then, I remembered hitting and going over a log on the river last fall...the wood wedged into the hole.

It puzzles me that Mercury decided to provide the speedo signal on their motors, with the pickup on the leading edge of the lower unit and subject to the exact problem you had. The old-style pickup units do not have that problem. Run over a log and the pickup just swivels out of the way. BTDT. Oh well...