Scott -

Thanks for the reply. Glad I'm not the only one going crazy trying to track this down. Please let me know if you find a solution.

-Greg

Since you have checked evrything in the wiring out, it sounds like it could be a defective gauge. If it were me I would send it back to the company for repair or just buy a new onr.

I've already bought a new one, which also is "bad?". I tried contacting their customer service but havn't gotten any reply. I'll probably call Eddie Marine (who I bought the replacement through).

-Greg

I had exactly the same problem with red line series oil pressure gauge. Tried too many fixes and finally installed standard oil pressure gauge (not red line series) and have had no more trouble. I like the red line as an idea but I would never see that little light anyway. Now my gauge is trust worthy. I never felt comfortable with oil pressure fluctuating before changing the gauge. Unless your dead set on running the red line series gauge I would just install a standard gauge and I think your problem would go away. Know anyone you can borrow a standard gauge from for a day and try? One last thing I have to mention and not to state the obvious but you are running a Gaffrig sending unit correct.

I have the same problem with one of their water temperature gauges. I also have checked everything shy of replacing the gauge, but I'm not convinced it is the gauge. Here's why: Temp read OK for a while (140F, HP500 engine) and then starts to creep up to 180-200, or may just "jump" to 180-200 and stays there. If I then move the tabs (K-planes) or change the trim on the drive, the temp gauge "jumps" back to 140 and may, or may not, stay there. Grounds are all daisy chained on the gauges, and I think all of the "hots" are, too. Temp gauge is the only one that does this! Checked ground by jumpering it direct, checked sending unit with ohm meter and tested it against a brand new sender, both read the same and reacted the same to temp changes. What bothers me, is that by applying a "load" on the electrical system (moving the drive or tabs), the temp gauge reacts (goes back to 140F). That indicates electrical noise getting into the signal wire, floating ground, or floating "hot" voltage. But why is the temp gauge the only one affected???

paradigm shift - Yep, running the second (now) Gaffrig sending unit. Never thought it was the real problem, but changed it to another new one "just in case". It's beginning to sound like Gaffrig has a real problem with this series gauge.

-Greg

I sent the Gauge and a letter out today I will post the results.

Ed at Gaffrig sent me a new gauge at no charge. He also (after I asked) talked me into changing my stock senders over to the units they sell. Not a big deal except that they are VERY difficult to get to, it took me almost one hour per motor with cut up hands and bruised ribs (man did that job suck).
I am not convinced this will be the solution since I have already changed the gauge and I have swapped the sending units. I did a lot of wire tracing to make sure all connections are good. Just can't imagine how the gauge can read pressure (erratic) but never below the set 10lbs and still have the light blink on and off. I will also add that they checked my old gauge and found no problems and were still willing to comp me a new gauge out of warranty.
I will post again after I get out on the water and let you know if the problem has been solved.

Scott

Hi Scott,

I have run the gauge with and without the Gaffrig senders, and have replaced the sender with no long-lasting effect (it did make it work correctly for a couple of hours, but I think it was a fluke).

Since I have two flaky gauges and one is on the shelf I played a few games with it. Running no ground just sender it will read off the scale high, but no "red light". Running no sender but ground it reads zero with the red light (no great surprise there). By connecting and disconnecting the ground I can get the red light to blink briefly, but not to stay on. I have never been able to duplicate the high with red light that it had before.

The "new" gauge and sender in the boat continues to be intermittent. It usually goes to "bad" mode (red light one and reads 25 psi with the engine off, and not surprisingly 25 psi higher than true when the motor is running) as soon as I turn the switch, but returns to reading "correctly" after running for a while. It will do this while the boat is setting still on the lift, so it's VERY unlikely it is a loose connection somewhere. So far it has never gone from "correct" to "bad" mode once reading correctly without turning the engine (power) off and starting a new cycle.

I took the boat down this morning to be pulled for painting. The gauge powered up as "bad", went to "good" about 1/4 mile after coming up on plane, and stayed "good" for the 45 min run to the ramp.

I'm just going to dump the red-line gauges when it gets back from the shop,. I need to find out whose white face gauges look similar so I can swap them out a few at a time instead of doing the whole panel again (since so far only one oil pressure and oil fuel level have been acting up).

-Greg

Only failure that I've had so far is moisture in the gauge. The culpirts have been replaced by Livorsi.