I have had speedometers and depth finders get clogged up before and stop registering before... this time my speedometer just stayed at an indicated 35mph. It slowly dropped to about 25mph over the next couple of hours.

Is this another case of something being clogged up or is this a mechanical failure of some sort? Do I have to pull the boat out for inspection or is this something I can investigate with the outdrive in the trailer position?

The boat is a '98 Formula 252LS with a 502MAG/BravoIII and coincidentally my depth finder also stopped working recently... I am assuming it is from weeds, lots of weeds this year.

Any input is appreciated,

Jamal

You have something jammed good in the pick up tube

S4HADI,
I'm with obnoxus on this one, I would say you've got something jammed in the speedo tube!!! Good luck with that one...that's an annoying problem!!

I've experienced that before...
Same thing: speed stayed at some level and it slowly dropped to zero over a period of an hour or so, then when getting back on plane, it took like five minutes to reach the proper speed and once again when stopping, it took an hour or so to drop back down.

In my case I had some wood debris jammed an inch or so in the speedo pickup tube. It wasn't enough to completely stop water from entering at speed, but enough to contain the pressure for a while until it dripped out slowly.

I agree - something is stuck in the small hole on the front of your outdrive. If you can see it you can try to pick it out with a needle or tiny drill bit. Be careful not to change the size of the hole.
Or, you can do it the easy way with some compressed air. If you put the drive in the trailer position you will see a little hose with a fitting that attaches to the lower portion of the drive. You may have to look from below to see it. It twists and then pulls out. You should see your speedo return to 0 as soon as you remove it. Then rigg up something to blow compressed air through the blocked passage in the outdrive.

I guess it is unanymous, I tried to feel around the lower part of my outdrive for any foreign objects and scrubed around with a brush... could not feel a thing. The speedo is back down to about 5mph's now and still will not register any speed.

Looks like I'll have to pull the boat out in order to fix it... the outdrive is still pretty far down from the swim platform when in the trailer position.

While she is out, what should I check for to clean out my depth sensor... not registering anything at all.

Thanks for the input.

Jamal

Just use this info when the insurance company asks "how fast does your boat go?" It'll help with the bill!

Use a 3/32" drill bit. Works best if you glue the drill bit into a piece of wood dowel. That way if you lose it underwater, it falls UP (yep, it floats). The pickup is in the leading edge of the gearcase. You have trash jammed in there. Don't worry about making the hole too big, it won't affect anything. It's just a pressure port and the calibration is all in the speedo.

The depthfinder issue is different. If you have a transom-mounted pickup then it probably has been knocked out of alignment. It needs to be mounted so that it has a full contact with the water at speed. There are adjustment slots and screws on the brtacket. If the pickup is inside the hull, then something has happened to the wire or the pickup has been dislodged form the hull.