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Author Topic:   Mercury SmartCraft: LOST ENGINE COM
jimmp posted 03-17-2008 03:07 PM ET (US)   Profile for jimmp   Send Email to jimmp  
I've been having a recurring problem with my Mercury SmartCraft system. When I start the engine after leaving the boat for about a week the words "lost engine com" appear and my guages fail to function. While I can still use the boat I usually have a nervous wait until it kicks in again after about 15 minutes or so and will then work OK. I've had no answers for this even from the dealer, who is also at a loss to deal with it. Can anybody help?
glen e posted 03-17-2008 03:55 PM ET (US)     Profile for glen e  Send Email to glen e     
Check all the connections from the engine to the gauge. Spray each connection with some elctric contact cleaner.
jimh posted 03-17-2008 06:58 PM ET (US)     Profile for jimh  Send Email to jimh     
Be very careful about spraying "contact cleaner" on any electrical connection, especially ones involving any sort of plastic or vinyl. Instead of a "contact cleaner" I would try a water-displacement spray, such as WD-40. In my experience (which includes about 40 years of hands-on electronic work), "contact cleaners" have to be used very carefully. The solvents in the cleaners can have strange effects on non-metal components.
glen e posted 03-17-2008 07:17 PM ET (US)     Profile for glen e  Send Email to glen e     
I use CRC QD electronic contact cleaner - impervious on plastic and reccomended by verado certified techs at two dealers in s fla...and wd-40 can harm rubber - another alternative is CRC - 656....
jimh posted 03-17-2008 08:12 PM ET (US)     Profile for jimh  Send Email to jimh     
Glen--I think the jury is still out on whether WD-40 can harm rubber. Its properties as a lubricant can cause problems with rubber drive belts, and since there may be quite a few rubber drive belts on a Verado, it might not be the best solution for that engine.

However, the original poster does not mention he has a Verado.

I have been spraying WD-40 on rubberized electrical cables and connectors for years and never noticed a problem. WD-40 has also been used for years to displace water from ignition systems using rubber insulation and rubber boots on the spark plugs.

CRC-656 is listed as a lubricant. S=Y

CRC-QD looks like a good product. It is listed as "a petroleum distillate and alcohol based precision cleaner designed as a alternative to CFC based cleaners." S=Y

I guess with the new environmental regulations about volatile organic compounds and chlorofluorocarbon (CFC) based solvents, you probably no longer can get those really great spray cleaners we used to use way back when. A little 1-1-1-trichloroethane would fix a lot of problems.,1,1-Trichloroethane

By the way, I agree with Glen--this SmartCraft instrument problem sounds like an intermittent connection. To find it, follow this procedure.

The next time the problem occurs, do not start the engine. Instead, locate the wiring harness between the gauges and the engine. Without disconnecting any of the connectors, try manipulating the connectors slightly while observing the SmartCraft display. You may be able to discover which connector is causing the problem by just slightly moving the connector and the associated wiring.

It sounds like the gauge system is receiving power, but it has lost the part of the connection used for the serial data stream. If there are different types of connectors, look for the ones carrying the serial data, not the power.

Also, make sure all the connectors are completely mated together, seated, and locked. I imagine that the connectors used are designed to be waterproof and to physically engage in a manner that locks them together.

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