Plugged Pitot Tube

[eagleman]

I purchased a used 200 horsepower Optimax where I was told the speedometer doesn't work because of a plugged pitot tube. I decided to work on it in the fall, because I have the GPS unit for a speedometer. I have been able to clean it out about 2 inches inward on the lower unit and I have tried blowing compressed air from the tube attached to the speedometer backwards through the motor. No luck so far. Anybody have any tips on how to unplug a plugged pitot tube?

[marine_man]

wow.. that is the definition of plugged I would say..

I have heard of guys taking a tiny drill bit and slowly (very slowly) running the drill a little at a time until it makes the corner to go vertical.

Good Luck!

marine_man

[Deitz Dittrich]

If you have GPS speed, what does it matter if your spedo works or not? The water Pressure Spedo's are not all that accurate anyway.

[eagleman]

marine_man...How far in before the corner to go vertical? It feels like I am hitting something solid, but unsure. I know the GPS is more accurate, but if I can fix this on my own I would.

[marine_man]

Boy, I don't have a good enough idea to even give you a guess.. it's been a while... I would put the drill bit in there and turn it a bit and see if you get wood shavings or metal filings. Don't do it fast by any means..

marine_man

[Surface Tension]

Have you gotten anything out of the hole yet like dried mud?

I don't know how far it is to the bend either but try a cable now. Something the size of bicycle cable. Put it in the hole and rotate it in a direction so the strands stay wound.

[eagleman]

First off, thanks for all the help so far. I really appreciate everybody taking time to read my email and making suggestions. I cleaned out some wood fibers with a needle yesterday. I am in about 2 inches and feel confident I am hitting something metal when I poke a coat hanger in there. I am pretty sure I am up to the vertical turn that marine_man spoke of. What I need to know is if I blow air from the hose that I disconnected from the speedometer end, will it blow directly out the pitot hole on the lower unit. I am currently working by myself, so I put some masking tape over the pitot opening and blew compressed air backwards from the speedometer end to the pitot tube and the tape did not blow off, making me believe it is still plugged. Perhaps it is plugged upwards of the vertical bend.

[marine_man]

If you blow air from the hose that goes into the lower unit it will come out the pitot tube in the leading edge of the gearcase.

marine_man

[eagleman]

So I need to take off the lower unit tube from the union fitting that connects it to the upper speedo tube. Have you done this before? Any tips? Thanks again.

[Ralph Wiggum]

If you have GPS speed, what does it matter if your spedo works or not? The water Pressure Spedo's are not all that accurate anyway.

Deitz,

Some of us are just anal retentive enough that they like everything to work correctly, regardless of if it is necessary. I suffer from this affliction, too

[marine_man]

Yes, that's what you'll need to do...

If you're mechanically inclined and want to fix this yourself you may need to remove the lower unit to be able to get at where the tube goes into the lower unit.

marine_man

[Deitz Dittrich]

Originally Posted By: Deitz Dittrich

If you have GPS speed, what does it matter if your spedo works or not? The water Pressure Spedo's are not all that accurate anyway.

Deitz,

Some of us are just anal retentive enough that they like everything to work correctly, regardless of if it is necessary. I suffer from this affliction, too

Sorry RW- I've had quite a few different boats, and used to try and keep the speedo working. I finally gave up on my first boat.. havnt had one work since.. Except on my new boat.. in which the speedo is connected to the GPS.. LOL

[eagleman]

Thanks everybody for your help. I got it unplugged. When I blew air backwards through the hose connected to the pitot tube, she blew clean. Thanks again.

[marine_man]

Glad to hear it!

marine_man