Speedometer not working

[Bduck]

Over a year ago my speedometer on my boat dash quit working. It wasn't a big deal since GPS speed is monitored & more accurate. At first when it quit I found crud plugging the pitot opening but after clearing that it made no difference. So I further let it go not to bother with it until yesterday. I went to the top of the motor where pitot tubing channels in and found it had pulled out real easy. Now I had to remove lower gearcase assy and spacer above that. I found where the tubing broke in to about an inch from pitot itself. Inspection of tubing revealed cracking of the full length of it being routed in channel of motor so I decided to replace a 12' section of the tubing that routed back thru transom and splice into remainder 15' to dash. As I finished this job up I next removed the shroud
between gearcase/spacer & upper motor and found lower engine exhaust housing covered in black soot. This soot has been seeping to outside of painted shroud that covers exhaust housing. I always had to wipe down shroud from a lite film of soot in a couple of places. Today is cleaning exhaust housing and inside shroud.

  

[wiperhunter2]

Over a year ago my speedometer on my boat dash quit working. It wasn't a big deal since GPS speed is monitored & more accurate. At first when it quit I found crud plugging the pitot opening but after clearing that it made no difference. So I further let it go not to bother with it until yesterday. I went to the top of the motor where pitot tubing channels in and found it had pulled out real easy. Now I had to remove lower gearcase assy and spacer above that. I found where the tubing broke in to about an inch from pitot itself. Inspection of tubing revealed cracking of the full length of it being routed in channel of motor so I decided to replace a 12' section of the tubing that routed back thru transom and splice into remainder 15' to dash. As I finished this job up I next removed the shroud
between gearcase/spacer & upper motor and found lower engine exhaust housing covered in black soot. This soot has been seeping to outside of painted shroud that covers exhaust housing. I always had to wipe down shroud from a lite film of soot in a couple of places. Today is cleaning exhaust housing and inside shroud.

  

Wow, that was a lot of work to fix that problem, how many hours do you think it will take you to get it working again? I have the same issue with my boat too, at least I know how to fix it now, thanks Rodger for sharing this with us? How about your RPM gage, you ever had a issue with it? Mine seems to be glitchy, it works most of the time but it jumps for no apparent reason and I'm just not sure how accurate it is.

[orangeversion]

Can you say something in more details about how you fixed it?

[Bduck]

Curt, I put it all back together shortly after routing the tubing with exception of the upper shroud so I can clean lower exhaust casing which is done now, its ready for duty. It doesn't take very long for me that's providing everything is in working condition and I'm not delayed for parts. I've taken apart a few outboards replacing impellers, re-ring pistons, etc. 
Yes, those RPM gages are glitchy, mine probably does the same thing yours does. My last boat also did. Boat manufacturers tend to contract out for good bulk deals for cheap operating instruments which we both have seen before. I have on the table to redo my dash replacing with descent quality gages. Looking to expand my dash by cutting out a larger opening and installing a larger panel as you can see in pic of my current dash. While a lot of guys enjoy the digital world which there is nothing wrong with that for more accurate readings, I like the old school of analog gages watching actual working instruments with needles. There are some cool looking gages still on the market.

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Can you say something in more details about how you fixed it?

After I removed lower sections of gearcase & spacer I was able to see channel on lower end in which I made my own snake to route from bottom to just under powerhead lower cowl. I attach new tubing at the top to the snake and pulled snake down thru the channel with new tubing. Then I fed remaining length of tubing thru bottom side of cowl inside of engine compartment where engine harness routes out to transom attaching it with an inline splice to old tubing so I can pull it thru to inside of boat transom area. 
Most newer engines today have a built in pitot with exception to the smaller kicker variety. Old style pitot is an external transom mount.  

[wiperhunter2]

That dash should look really nice when you are done Roger. How much does a new RPM gauge cost?

[Bduck]

That dash should look really nice when you are done Roger. How much does a new RPM gauge cost?

There are many styles with a wide variety of prices. I'm thinking in the range of $60-80 for a descent gage as my search will be in the off idle season. I've seen kits starting at $250+ with RPM, Speed, Oil Press, Temp, Voltage, & Fuel gages. 

[wiperhunter2]

Good to know, if I end up getting a new RPM gage, hopefully I'll be able to modify my dash to fit it, if it's not the same size as my old gage.

[Tin-Can]

Roger, do I detect the terminology of a past aircraft mechanic ?  Pitot tube ? (was an AF aircraft electrician for 20 years)  Or is that what it is also called on the boat motor?  My little 14 foot has no dash, so I have relied on my GPS since I purchased the boat in 2007.  But the first boat I had in 2003 was a 17 foot with a 115 Merc OB. The speedo on the dash console never indicated until boat was up to at least 5 mph. just got in the habit of ignoring it. 

[Bduck]

Roger, do I detect the terminology of a past aircraft mechanic ?  Pitot tube ? (was an AF aircraft electrician for 20 years)  Or is that what it is also called on the boat motor?    

Forrest, not to be in denial yes the lingo follows one after 38yrs of using it or you can call it brain washing. However, I will be continuing to use it as you have also understood the lingo too. It is also used in the boating world as an example in the link I posted here. To further go one step into the lingo the term tech data is everyday talk but we also call it searching a TO.    You also have a quality skill as an electrician that is very useful in many areas outside the AF especially in the rigging of certain boat accessories.   
https://www.wholesalemarine.com/sea-dog-...-tube.html

[Tin-Can]

Roger, do I detect the terminology of a past aircraft mechanic ?  Pitot tube ? (was an AF aircraft electrician for 20 years)  Or is that what it is also called on the boat motor?    

Forrest, not to be in denial yes the lingo follows one after 38yrs of using it or you can call it brain washing. However, I will be continuing to use it as you have also understood the lingo too. It is also used in the boating world as an example in the link I posted here. To further go one step into the lingo the term tech data is everyday talk but we also call it searching a TO.    You also have a quality skill as an electrician that is very useful in many areas outside the AF especially in the rigging of certain boat accessories.   
https://www.wholesalemarine.com/sea-dog-...-tube.html 

  You got that right Roger.  I still use LOTS  of terms, abbreviations, acronyms, 24 hour time, etc      .  My family all understand it, and of course being so close here to Hill, many civilians also understand lots of it.   But every now and then, I'll say something and someone will look at me like  I just switched from English to Hindu.    .