Where to drill for telltale outlet?

[glennkil]

My 1974 Evinrude 25 has no telltale water outlet. I'm keen to add one to monitor correct water flow as it has had some overheating issues.<br /><br />The logical place seems to be on the exhaust cover but the cover has two chambers. A large chamber that makes up about 75% of the cover plate and another segregated top chamber that is about the other 25%. The top chamber "seems" to be fed by the uppermost hole in the thermostat housing which actually has a rubber plug blocking it that two local dealers confirmed was a factory modification (in Australia anyhow). I was planning on drilling the lower chamber (near its top) and tapping to fit a automotive barbed fitting like that found on brake calipers for bleeding. Am I off the mark?

 

[glennkil]

Re: Where to drill for telltale outlet?

By the way there is not much thickness in the metal of the housing. I don't think that there would be enough to tap a thread into. Suspect that fitting will need a washer and nut on the other side of the housing to seal properly. Comments?

 

[OBJ]

Re: Where to drill for telltale outlet?

Don't have a cover right in front of me Glenn but yes, most likely you could rig a tell tale. I would also put it as close to the top of the cover as possible also. This would help vent off the chamber and keep it full. Shop around for a fitting.....possibly an auto parts store may have a smaller type fitting that would work. And let us know how ya' make out.