speedometer replacement

tfret

Member
Joined
May 6, 2007
RO Number
26185
Messages
236
I just bought an 84 ski boat. When I test drove it I didn't pay too much attention to the gauges, since the seller already told me several didn't work and really should all be replaced. I did notice the speedometer was up to 55 when I opened her up to see what the top end was like. So if figured the speedo must be pretty accurate. After changing all the gauges the new speedo doesn't seem accurate. I didn't replace the tubing and pick up. Is the pick up matched to the gauge and need replaced too? Your thoughts please.
 
I wouldn't have bothered with the speedo gauge. They are notoriously wrong or, like mine, don't work at all! I just track my speed with my GPS if I really need to know. Pay more attention to your RPM. That will give you better info about how your boat is performing and the health of your engine......

And forget about those "5MPH" signs. It isn't the speed, it is the wake. Look behind you to what your wake is doing. If you can see a wake from your boat in a "5MPH" zone, you are going too fast.
 
They are all pretty standard. The pickups get clogged. You can clean them out. If there is enough opening to create a vacuum without restriction, they probably work okay. Sometimes they only last for a year. I clean mine every year. At higher ski boat speeds they may not be too correct. I'm happy with mine, and I have a GPS as well. Good luck.
 
So the gauge actually responds to vacuum? I didn't know that, I thought it was static pressure that made it work. I like to slalom at 28~30mph, so I like the gauge to work well in that range. But that is down at the bottom of the gauge I bought. I probably should have got one with less top end and more mid range scale I guess..
 
What Flutterby said...rely on RPM'S. The speedo is the most worthless gauge in the boat. Get a GPS if you must have some indicated speed over ground.
 
they make gps speedometers with a traditional looking 4 or 5 inch gauge they are extremely accurate and come in a varity of sizes and speed ranges they are right on even at 150 mph or more and have a memory recall
 
Actually those OEM speedo's work off of pressure. Water is forced into a small hole on the pitot tube pickup and this creates a pressure in the hose that pushes the needle on the gauge.
 
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