06-12-2017 03:25 - edited 06-12-2017 03:49
The 4 service lights on it work (No oil, hot, check engine, no oil etc), but no sign of the revs moving. Worked fine last year, but nothing since the winter and it being serviced at an authorised dealer who plugged into their system etc.
Perhaps the service was a coincidence?!
Tried tapping/ leaving indoors etc to dry out. Checked all the various wires/ connectors etc but can't see anything loose or out of place.
Is there anything on the engine end to check specifically?
Anyway, is there anyway I can test the 8 pin plug that goes into the back of it with a multimeter? If so, which pins and what should I expect from each?!
It's not a digital rev counter by the way - has a mechanical arm.
06-12-2017 06:39 - edited 06-12-2017 06:42
The quickest way to test the gauge is to temporarily plug in a known good gauge. That would tell you right away if it is a gauge or wiring issue.
Actuate the 5 and 6 pole PUL / REV adjustment back and forth in case there is a bit of corrosion on a contact. The final setting should be on 6.
A dealer can hook up his or her laptop and see if the engine is generating a tachometer signal and an ohmmeter can be used to check the wiring from the EMM to the guage connector to make sure it is continuous. Since the lights work, the gauge has the required power and ground circuits operational.
Thanks for that - can't seem to find a gauge to switch it with unfortunately.
Good plan on the 5 and 6 pole - will try that. Sadly i'm not with the boat for a few weeks now so might be a while before I can revert back with results... just trying to come up with a list of things to try!
Out of interest, is anything disconnected when they plug in their laptop or do they plug into a blank port? I wonder if they can of distrubed something during the service?
If you want to check, unplug and re-plug in the two 6 -pin connectors at the engine where the boat harness attaches. Look for a bent, broken, or deformed pin on the gray wire in one of the 6-pin connectors as that is the tach signal. It is in the connector with the 4 brown or tan wires.
Great, least I know what I am looking for now - thank you.
Do they have to unplug something when they attach their computer or is it just a cap on it anyway?
The laptop access point is a special triangular plug, 3 wires, red, black, white.
a week ago
Thanks for all the replies.
I have tried everything suggested and still no luck. I suspect the guage is faulty...
Checking the voltage on the grey wire shows an increase in volts when the revs are increased but I was unable to measure in the required hertz...
Don't remember what the reading was unfortunately but it did increase as the revs did.
Any more suggestions?
Finally, am I stuck with using the guage only going forward?
a week ago - last edited a week ago
Unless you have a trained technician check over and troubleshoot your engine, your only DIY recourse is to find or borrow a known good gauge and temporarily plug it in to check the results.
If you have the oil metering system, sometimes called a VRO, installed and operational, disconnect the 4-wire connector from it and retry. In very rare instances, faulty electronics inside the No-oil alarm circuitry can affect the tach signal
a week ago
do you have a marine surplus store near you?
we have one in bradenton, fl and they have TONS of these gauges. That and ebay will be a cheap way to get a test gauge/tach