speedometer - pipot tube??

bxs122

Recruit
Joined
Jun 16, 2008
Messages
5
I have finally given up the online searching and decided to register here where the community is large with mercury outboard owners.

I am a somewhat new owner of a Ranger boat with a two-stroke 90 Mercury outboard.

I don't recall upon receiving the boat whether the console speedometer was functioning. Unfortunately not soon after receiving the boat I took ill and the boat sat a few seasons unused.

This year I have been using the boat at least one to two times a week and just loving time on the river.

Now that I am more familiar with the boat and the motor (beware of Hot Foot flooding ewwwww.) I would like to figure out why my speedometer does not work.
From the research so far it sounds like the Mercury I have is a pipot tube style and so if I follow the back of the speedometer out to the outboard then I should be seeing a pipot connection somewhere in the lower unit?

Any help would be greatly appreciated.
 

davidf5252

Petty Officer 2nd Class
Joined
Apr 19, 2008
Messages
168
Re: speedometer - pipot tube??

I just bought a boat with a 88 mariner 115hp and my speedo doesnt work either... i think there is a tube that runs to the LU and it works off water pressure but i dont know how to check it or clean it...

so im looking for the same answer!! good luck!
 

bxs122

Recruit
Joined
Jun 16, 2008
Messages
5
Re: speedometer - pipot tube??

I just bought a boat with a 88 mariner 115hp and my speedo doesnt work either... i think there is a tube that runs to the LU and it works off water pressure but i dont know how to check it or clean it...

so im looking for the same answer!! good luck!

Subscribe to this post - from the quick reads and searches here it is looking very positive we'll find an answer to this.
 

davidf5252

Petty Officer 2nd Class
Joined
Apr 19, 2008
Messages
168
Re: speedometer - pipot tube??

Subscribe to this post - from the quick reads and searches here it is looking very positive we'll find an answer to this.
Yeah this place is awesome...I have a 1956 johnson javelin 30hp and the guys in the Johnson forum helped me a TON!
 

TommyA

Petty Officer 2nd Class
Joined
Jun 3, 2008
Messages
148
Re: speedometer - pipot tube??

The lower unit has an opening on the forward side of the prop. Water pressure will push in the tube and cause the speedometer to register. Look for a small tube threading up from the forward side of the lower unit and carefully unhook it at the first joint in the line. If you can not blow through the tube going down the engine then there is a blockage in the opening on the front of the lower unit.
 

bxs122

Recruit
Joined
Jun 16, 2008
Messages
5
Re: speedometer - pipot tube??

Thanx TommyA,

Found the tube then found the small hole - it is packed with dirt. I assume it was mud at one point but has since dried.

The hose coming from the lower unit is on pretty tight at the first joint. I'll hit it with a little heat to see if that loosens it.

If I get the hose off what is the best way to clear the clog in the lower unit? I tried digging it out but realistically think I could have stayed there all night getting little pieces. Can I shoot water down the hose to flush it?

thanx again for the help.
 

TommyA

Petty Officer 2nd Class
Joined
Jun 3, 2008
Messages
148
Re: speedometer - pipot tube??

A small piece of stiff wire makes for a good digger. Keep spraying water at the opening and try to squirt water down the upper tube end. If you have a marinade injector with a small enough end that might make it easier from the upper side. Last one I cleared was with the boat in the water. If you can get some water down from the top compressed air will help force it back down. Remember the shortest path for removal is in the direction that the dirt came from.
 

bxs122

Recruit
Joined
Jun 16, 2008
Messages
5
Re: speedometer - pipot tube??

thanx for the additional information - I dug quite a bit out of the little hole then shot some water in there and dug again.

The line from the speedometer has a splice at the motor which is a perfect spot to pull and send water in the opposite direction. Unfortunately the spliced tube has a shrink wrap sheathing which I don't have any of to replace so am reluctant to cut it.

I'll see if my digging was enough - if not then I'll try and clear from the connector mentioned, after I buy some tube wrap or whatever it was they used in assembly.

Again thanx.
 

j_martin

Admiral
Joined
Sep 22, 2006
Messages
7,474
Re: speedometer - pipot tube??

thanx for the additional information - I dug quite a bit out of the little hole then shot some water in there and dug again.

The line from the speedometer has a splice at the motor which is a perfect spot to pull and send water in the opposite direction. Unfortunately the spliced tube has a shrink wrap sheathing which I don't have any of to replace so am reluctant to cut it.

I'll see if my digging was enough - if not then I'll try and clear from the connector mentioned, after I buy some tube wrap or whatever it was they used in assembly.

Again thanx.

The shrink tube is a patch. don't worry about it. Cut it off any way you can, and get a plastic splice from menards, or Napa, or wherever. Brass is OK, just not needed. It ain't gold parts or rocket science, just a barbed splice with about 10 lbs of pressure max on it, and no real damage possible if it should let go, like the plastic line under your kitchen sink.

While it's off, blow into the line into the boat with your mouth while peeking over the transom. You should be able to see the speedo jump a little, verifying that's all OK.

I usually use a little twist drill spun between my fingers to get the mud out of places like that.

hope it helps
John
 

bxs122

Recruit
Joined
Jun 16, 2008
Messages
5
Re: speedometer - pipot tube??

The shrink tube is a patch. don't worry about it. Cut it off any way you can, and get a plastic splice from menards, or Napa, or wherever. Brass is OK, just not needed. It ain't gold parts or rocket science, just a barbed splice with about 10 lbs of pressure max on it, and no real damage possible if it should let go, like the plastic line under your kitchen sink.

While it's off, blow into the line into the boat with your mouth while peeking over the transom. You should be able to see the speedo jump a little, verifying that's all OK.

I usually use a little twist drill spun between my fingers to get the mud out of places like that.

hope it helps
John


sounds like a plan - I was thinking of cutting the shrink tube anyway, speedo isn't working now so what is there to lose if it comes off while on the water.
 

lowell7963

Seaman Apprentice
Joined
Jun 18, 2009
Messages
48
Re: speedometer - pipot tube??

My 50HP BF is the same, no speedo. The connector is gone just a small tube protruding up from the lower unit. It is not a problem.
 
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