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Outboard query

R

redbayhilux

New member
Hi

I have a MERCURY OPTIMAX Saltwater series 200 HP. Engine runs perfectly well and starts everytime without any issues. Only done 280 hours so far, I think she is a 2005 model.

However, I did notice on one or two occasions the SMARTGUAGE showed "Engine Data Bus" message then disappeared ? any idea what this was or indicating ?

Secondly, brought the boat & engine in for servicing last week to be advised by the dealer that the compressor head needs changing.

Can you advise if this is a common issue on this engine ? or what caused this need for replacement ??? Any advice would be appreciated.

Thanks JP
 
I will start with the "engine data bus" message.

You get that when the connection is lost between the tach (smart gauge) and the engine computer - so it's telling you that either the cable is disconnected, has a cut, short or any number of other issues (including a toasted component at the motor side).

Think of it like the "no signal" sign you get on a TV when the cable or satellite signal is lost - nothing wrong with the TV (or gauge in this case), just not getting any signal to display.

The compressor head.

Although the Opti's have been around now for a little over 10 years, they are not so prolific that quirks or legacy issues are well known.

I have only personally seen a handful of Opti's and have never heard of a compressor head problem.

The compressor is basically a single cylinder "motor" that provides the (roughly) 90 psi that the fuel and air rails need to run the injection system.

In this design the reeds for the compressor are in the head (really sandwiched between the head and the cylinder).

So if there was an issue it would seem more likely to me that it was a reed failure (there are two sets of reeds - intake and exhaust to allow air to be sucked in on down stroke and then "exhausted" - sent to the air/fuel rails on the up stroke with them opening/closing opposite to each other) as opposed to a head failure, unless either an o-ring or seal failed between the head and the reeds - but again, that wouldn't require a new head.

So at least on the recommendation of a "new head", I would be asking exactly what the issue is and if you get a rather confusing answer I may look for a different tech and get a second opinion...
 
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