Posted by ErichBW on 10/15/10 - 8:35 AM
#1
I am relocating the water pump indicator outlet fitting from the side of the exhaust manifold cover to the top of the cylinder head on my 1993 Johnson 70 per service bulletin 2276R1. Curently there is a tee that routes one way to the water pressure gauge and the other way to the tell tale. The bulletin calls for plugging the lower hole. It did not say if it would be ok to keep the lower hole for an outlet to the water pressure gauge and using the newly drilled upper hole for the tell tale. The bulletin only details the outlet for tell tale instalation. I also had read that if you don't want to drill you can just reroute the hose "over" the powerhead. Is this acceptable or as effective? My guess is probably no? Any input on this topic is appreciated. Thank you.
Posted by tedious on 10/15/10 - 10:09 AM
#2
Erich, when I did this job on my 89 70, on which the previous owner had installed a new powerhead, I found that I did not need to drill - there was already a hole in the top of the exhaust cover. I just had to swap the plug for the hose nipple and I was in business - I hope you are as lucky!
I can tell you, for sure, that just routing the hose "up and over" from the side outlet is not as effective as relocating the nipple - I just did the reroute first, and still had overheating problems. After doing the full job, everything was fine!
I think moving both sensor and telltale to the top nipple would be the way to go - then you'll know you have pressure and flow right to the top of the motor.
Tim
Posted by seahorse on 10/18/10 - 2:52 PM
#3
For better pressure accuracy, run the gauge tubing from the side of the exhaust cover where the overboard water tell-tale was originally.
The top fitting for the tell-tale is needed to bleed off trapped air in the block, plus with the tell-tale flow, and pressure reading there from a Tee fitting would not be accurate.