Jump to content

Tachometer Problems

Recommended Posts

I last posted on this on the Waterways Bounty Boats section.


Here goes with the latest saga of the Faulty Tachometer.


Having carried out all tests to establish what had gone wrong with the Tachometer, it became clear that the Tachometer generator was not giving an output.     On my Bounty the Tachometer generator is at the rear of the engine inboard and is positioned beneath the manifold driven from the camshaft via a speedo type drive through a long shaft to a dog tooth drive into the generator.    I then set about removing the generator, the nuts on the shaft are right hand thread but the main nut on the generator is left hand thread.    Therefore it soon became clear that in the attempt to remove the generator any movement on the nut would send the generator upwards and foul against the drain stud on the water jacket manifold.     The option to remove the manifold was out of the question as I thought this would lead to more difficulties and the removal of the drain stud was impossible as it was seized and I did not wish to do damage to the water manifold.      So upon persistence and a lot of blaspheming I manage to remove the generator but in so doing bent the drive into the speedo type drive.


Taking the whole thing home and straightening the drive in the vice I proceeded to establish what was wrong with the generator.  The whole thing is a sealed unit and to strip it down the ring around it had to be cut away.     Once inside I could see that the plastic drive inside it had shattered and therefore was not turning the actual generator.  


My only course was to replace the unit.     After extensive investigations and internet searching the only place I could get the unit was from America.  Here came the shock.     They wanted around 250 dollars for a new one.   However I managed to find a different supplier which unit was compatible and made in Czechoslovakia and who wanted around £60 but the delivery from America was to be up to six weeks.   I decided upon this option as I had gone so far down this route that I could not turn back.  





Upon its arrival which was in fact 3 weeks, tracked.   I went back to the boat to attempt to fit it.  What a nightmare!!!    It was impossible to locate both ends of the drive and keep it engaged in the generator because of the lack of space between the drain plug and the flywheel.    Eventually after having the threads cleaned on the shaft by a kindly engineer, I managed to get enough movement to get the generator in and out relatively easily.   However I still could not locate the drives.   My only answer was to raise the drive slightly by putting a small nut over the square speedo end of the drive to hold it up some 8th of an inch.  I then managed to get enough movement downwards on the generator to locate it.    Finally upon starting for the umpteenth time the taco worked.


I am obviously concerned as to how long this fix will last,   hopefully forever.     In hindsight it would have been a much simpler job to have replaced the taco head and wired it to the alternator.  What put me off doing this in the first place was the prohibitive price of the Taco head.    At that time I did not realise the costs involved in my new generator.   One thing is for certain if it goes wrong again the option of a alternator driven tachometer will come to the fore.



  • Like 1
Link to comment
Share on other sites

Hello Brian,

It sounds as if you have been through the mill on this job and it would have appeared that you have had to conjure up a third hand to fit it.

The only saving grace is that this is something you have done yourself and have not had an engineer costing £40 to £60 per hour on the job; or you have had to sell the boat to pay for it.

I am sure that any Bounty Owners will be greatfull for your input on this issue.



Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Sponsors

    Norfolk Broads Network is run by volunteers - You can help us run it by making a donation

  • Create New...

Important Information

For details of our Guidelines, please take a look at the Terms of Use here.