Banderlog.com

[Squrtin Squeeek]

OK, now that i know that no wires have been moved or changed, dont switch the wires i mentioned before. Try this. Get a piece of 10-12 ga. wire, hook it up to the - battery post and hook it to the engine block. Turn the key on and see what happens. Also, do you have a power strip on the back side of the engine ?
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www.ExtremeMichiganBoats.com

[Big Nasty]

[keatonboat1]

Thanks Kris. Yeah, would have thought it would be something easy like a ground wire coming loose or something visually easy. I checked the ohms on both the water temp and fuel level and they appear to be ok - not infinite or shorted. Very odd. Also, I don't believe these gauges have any internal resistor and there are no fuses (at least that I'm aware of).

Mark
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Mark
www.keatonboat.com

[keatonboat1]

Just heard from a guy associated with SW gauges. He said to check for the gauge part numbers as he thinks that if the ground and power is daisy chained that one of the gauges might have an internal resistor that may have crapped out causing issues that I'm seeing. I'll check as it can't hurt.

Mark
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Mark
www.keatonboat.com

[keatonboat1]

I was able to get the numbers off the water temp and Oil pressure. The water temp appears to be 4652R and the Oil pressure looks like 82304. From what I can see on the voltmeter and fuel level neither of those end in R. I'll have to pull the stereo to get the complete number off those gauges.

Also, what's odd about the water temp gauge is that when I turn the key to on it will peg to left (cold). When I turn the key off the water temp and fuel gauge needles will move back to the right. However, after I disconnect the battery completely if I now turn the key to "on" the water temp needle will move slightly to the right towards hot and will continue to do so each time I turn the key from off to on until reaching a certain point at which time the slight movement of the needle appears cease, although to my eye it appears to ever so slight quiver when I turn the key from off to on with the battery disconnected.

Here's some other info - not sure if it helps.
When I measure the resistance between the ignition wire coming off the alternator to gnd I'm getting around 420 ohms. This is independent from the ignition wire going from the terminal block to the ignition terminal on the ignition switch and independent of the wire going to the coil.

When I measure the ignition wire from the terminal block that goes up to the ignition switch without it being hooked up to the ignition wire from the alternator I'm getting around 64 ohms. So, when I hook up the ignition wire from the alternator to the wire going up to the ignition switch I've got the 64 ohms.

So,
1. Not sure if there should be 420 ohms on that wire coming off the alternator to gnd

2. Now sure why I have 64 ohms on the wire going up to the voltmeter with it being hooked up to anything other than the gauges. I removed it from the water temp gauge and ignition switch up at the gauges and I still have 64 ohms on that line. I guess I can remove the ignition wire from all the gauges and ignition switch and the terminal block to see what the meter reads.

Mark
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Mark
www.keatonboat.com

[riverdog]

I don't know but if you turn your ignition switch and everything goes haywire, I would have tried that first before all the work. It's an $8 part and takes five minutes to check...I've seen stranger things happen over an ignition switch such as engines trying to start themselves when no one's around and no key in it.
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Confucious Say; One who go to bed with ichy butt, wake up with smelly finger...

[keatonboat1]

Well, took my boat up to Stringfields in Rancho Cordova today. What a great guy. If anyone has any electrical issues be it boat or car the guy is great. He checked things over and determined it had to be the temp gauge sending unit. Since he didn't have any Stewart-Warner stuff I told him I would go ahead and find a sending unit and try it. Also, to my surprise he didn't change me anything!!

Also, it appears the fuel gauge was a red-herring. I went ahead and put some gas in the tank before I went up to Stringfields and when I got there the gas gauge was reading the correct value. I can only assume that the float was stuck or it was just really low on gas.

I went over to Commercial Speedometer Service in West Sac. Another great guy. He had the exact S-W sending unit I needed and told me he thought that based on the symptoms he thought the sending unit was it, but if it didn't work out just bring it back.

Anyways, when I got home I installed the sending unit, and went ahead and fired up the boat running some water through it and within a few min. the gauge was moving up and reading around 150 degrees and then proceeded up to about 160 or so when the thermostat must have opened as it stayed pretty much around 160 or so the remaining time I ran the engine.
After shutting the engine off and turning the key to "on" the gauge needle did not peg to the left as it had before. It pretty much stayed where the needle was when I turned the boat off.

So, at this point I can only assume the sending unit was bad and everything appears to be working correctly.

Thanks to all for the suggestions.
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Mark
www.keatonboat.com

[Tahiti350]

glad you found the issue. thanks for posting up the final answer...
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Gary B> Tahiti350
The 1/2 Whacker Guy, Now fully Whacked
'86 Eliminator Daytona w/ 21' 220 Yamaha
'80 Tahiti 18ST w/ 350 SBC/OMC 800
(now in pieces )