'96 90hp on my tunnel skiff...

Running fine, tach is working, pressure gauge showing what it should be...

Tach will quit, and wp drops. WTF??? These two should have nothing to do with each other. Then tach starts again, and wp pops back up to normal.

Not sure where to even begin...

my first guess is a ground problem somewhere in the electrical system.

THAT'S CRAZY!!!! Those two guages are not tyed together by any means other than the light. One's mechanical the other is electrical. The only possibility would be that whenever the tack "dies" it's going to ground and the wiring for the tack is bundled behind the water pressure guage producing an electrical magnet that is effecting the needle on the w/p guage. But there again too, the w/p guage is mechanical in make-up and the magnetism would have to be so great that your hair would stand on end if that happened. So if you get this problem figured out, It will go done in Ripply's believe it or not......

Hehe....Pat, you must see some weird stuff doing this everyday. Every WP gauge I've looked at (a few) was completely mechanical. However, I recently corrected some gauge malfunctions on my boat by cleaning the ground and light connections. Same type of problem, too. I used Corrosion X on everything. It has worked well for me for corrosion problems.

Artie

Same things I said when I started looking at it. I don't even have lights hooked up to anything, the tach has it's little wire running to the control box, the wp gauge has it's little tube to the motor, nothing connected, or even close at all. These are the only two gauges there is.

I'd rather not run it until it blows to see what the real culprit is, but hopefully threw out something that anyone's seen before.

Unless you have a Stator shorting out causing a Field anomolly to spike thru the engine block knocking out the Tach and sending Voo Doo signals to the W-P Gauge/ I am not knowing??

Bazz

man, you need a priest, not a mechanic!

actually, there *is* a connection between those two gauges: the drive train......those motors don't happen to have a water-cooled rectifier/regulator do they?

I guess I'll just run it till it blows.

It is the rectifier.

Water pressure gauge is mechanical until it is converted to an electrical signal and then routed to the gauge. A fully mechanical WP would require a water hose to be routed to the gauge on the dash and I am sure those type gauges were replaced long before '96. If you got a hose hooked into the back of the WP gauge - then I am wrong

tack comes off of rectifier, merc rectifiers are usually damaged as a result of a battery short or if you disconnect battery while engine is running, i know folks use there trolling battery to start a motor sometimes if engine battery is dead ,but use jumper cables ,with no place for the current to go the rectifier cooks

The pressure gauge is mechanical, I just have a hose routed from the block to the gauge, which is why this had me so stumped.

I'll check the rectifier, but it's never been jumped, or disconnected, but 11 year old motors do get squiggly.

I was under the impression only the stator would cause the tach to go funky, and I just replaced it not very long ago, but I'll dig a little deeper.

tack comes directly off of the rectifier, check the setting on the back of tack,work the setting dial back and fourth a few times,remember to put it back on the original setting

Squiggly? Hehehe....is that a technical term....I think you need an exorcist....maybe your pressure hose is leaking at times and spraying the tach....Sorry, I thought I was the only person that had those types of stupid problems....

Artie

I'm looking for "voodoo priest" in the yellow pages now, I'm sure there's more than one listed in Austin.