tssteph

Where is the best place to mount a speedometer pickup at on a single engine transom? Starting from the center of the boat and working out I have the outdrive/pad, then a bunk, then a strake, then another bunk and then the trim tab with some distance between each of them. Is the best place between the outdrive and the first bunk or between the two bunks close to the strake?


thanks
Brian

Scott

I put mine in a box and through it on a shelf
Before you put holes in your transom consider a GPS speedo. If this is not a option for you then find the cleanest (water) location air will effect it. If it was me and that was my only choice I would call the factory they should know what works and what doesn't.

tssteph

I have a hand held GPS for "tuning" but I would like to know the general speed when cruising around and don't really want to spend the money for a GPS speed-O.

Thanks.

Griff

Mines about 6 inches off center to the starboard side and runns about 1 1/2 deeper than the hull. It needs to be in clean water to work properly.

Can't you hook it up to the drive speedo pickup????
That would be my first choice.

Macklin

Spend the money for a GPS speedo and kiss the days of clogged pitot tubes away!! You will not regret it.

Dock Holiday

The only thing I would mount is a GPS antenna!

mcollinstn

Outdrive pitot.

If yours is stopped up, clean it out with an .093 drill bit. The tube depth is around 2 1/2 inches. You should be able to get a drill bit that deep into the stainless pitot sleeve. Get yourself an extra drill bit and rough up the shank with a grinder. Epoxy the bit into a piece of wood dowel. Now you have a floating pitot tool you can use whenever you get trash in it. If you "drop" it while you are using it underwater, it "falls" to the surface. I've used them for years.

The only other part on the gearcase pitot that can fail is the plastic fitting on top of the lower. Replace it with a brass one if you are in freshwater, another plastic one if you are in salt.

For keeping the speedo tube on the fitting, I recommend using good quality heatshrink as a clamp. When you heat the shrink, it also forms the vinyl tube to the barbs on the fitting.

There. Problem solved.

tssteph

It must take a S curve in there somewhere. I had the lower unit off and ran a long piece of wire in from the top and from the pickup hole, the two never hit each other, also use a little muratic acid with no luck, 90 psi of air no luck. Gave up and put the lower unit back on.

Brian

mcollinstn

No, it's not setup like that.
The two holes TEE into each other.
The pitot hole is around 2 1/2" deep but the top hole comes straight down which puts it around 1" from the front of the leading edge or so. The casting has a groove around the hole that lets the pressure sneak by the stainless liner to the vertical hole.

The stainless liner tube WILL COME OUT. If you use a 1/8" diameter drill (or maybe it's a 3/16") it will "grab" the tube and you can pull it out of the gearcase to clean it out.

You don't NEED to pull it out, though. You just haven't drilled far enough from the pitot side.

Like I said, run a .093 drill into the tube 2 1/2 deep. It's best if you hook the hose up to shop air regulated down to 30 psi or so, and drill till it shoots air at you. There's NO WAY for the vertical hole to get stopped up unless your friend poured marinetex into it...

If you've got a Mercruiser manual, it shows a good picture of the cross section where the pitot tube is. Then you'll see what you're dealing with.

mcollinstn

the tube is even available separately if you want it (see item #9A).

http://www.mercruiserparts.com/Show_...+%28BRAVO+I%29