Mercuiser 5.0 going into guardian mode

[USMC_EOD]

I recently had a remanufactured enging installed in my 2002 Chaparral 243 Sunesta. The new engine has closed cooling and catalytic converters which required a wiring harness to be plugged directly into the batteries. The dealership doing the work was about as incompetent as they come as I was pointing out the problems to them before they could figure it out. Now that the engine is in and running I keep getting an audible alarm and the engine goes into guardian mode every time I try to get it up on plain. I took it back to the dealer once with this problem and they replace the sending unit on the power steering pump that was bad. I took it out again and had the same problem. I also noticed that the RPM gauge jumps up sometimes when I'm not giving it gas. Does the computer need to be cleared of error codes from the bad sending unit? I was also thinking I may have some type of electrical problem with the RPM gauge spiking like that. Any ideas what my problem is?

 

[alldodge]

The newer engines have another switch located on the throttle cable plate. This switch tells the computer if the engine is in gear or neutral. If this switch is misadjusted the computer thinks it's in neutral and will not let the engine rev up, and an over speed alarm will go off.

Also the engine has a separate wire which must be connected straight to the battery (clean power)

With the RPM gauge jumping you could also have a bad connection to ground. Since the motor was just installed a bad ground would be my first thought

 

[Fun Times]

New engine serial number is and old serial number was? and do you have an Alpha or Bravo stern drive?

 

[USMC_EOD]

The old engine SN was 0M356713 and the new SN is 1G341647 and it's a Bravo drive.

 

[thumpar]

Have they tried to read the codes?

 

[USMC_EOD]

They are waiting on a new cable to hook up to my computer. I guess they had a bad resister in the old cable.

 

[alldodge]

Was hoping FT would come in, he is probably doing the holiday thing. Looked up 1G341647 and it doesn't show up for me. Probably a Merc dealer only site

 

[Fun Times]

I was hoping to confirm a few things as far as engine match up was concerned but the newer serial number is not coming up for me either. While the 1G***** could be for a brand new engine as they are working their way up the 1A, 2B, type numbers....I'm only use to seeing the 1G numbers as remanufactured engines.

While the warning horn could a high number of things, the list of things AllDodge mentions to inspect in post 2 would be the first few things to inspect without having a scan tool at the ready.

If what ever is sounding the warning horn repairs itself/gets repaired, the horn will stop sounding on it's own so no you wouldn't need to clear any faults using a scan tool afterwards.

Be sure the battery with the clean power wire harness is always fully charged. Do you have one or two batteries on a battery switch?

 

[USMC_EOD]

It is a remanufactured engine from mercuiser. The cable came in and they weren't able to locate any error codes. They gave me a software update for my computer and I took the boat out and got the alarm again. I have 2 batteries hooked up and they are both new and fully charged. I looked at the neutral switch and don't see how it could be adjusted. It has 2 mounting screws that have no way to adjust them. The alarm goes off steady until I back off the gas. I don't know if this is guardian mode. I've noticed that if I don't back off the gas the engine doesn't run smooth. And after the alarm goes off and I back it down to idle the engine idles a little rough at times. Sometimes after I back it off there is another alarm that goes off that is 2 alarms spaced about a second apart. It doesn't always give me the 2 alarms though. Most of the time it is the steady alarm and I back off the gas and it goes away.

 

[Fun Times]

If the shift cables were to be out of adjustment from installing a new engine, then it would have an affect on the switch. You'd adjust the cables not necessarily the switch. There's a few procedures to adjusting the cables during installation that can be over looked at times....Bear in mind that this is one possibility out of many that could sound the horn like that.

Someone that understands how to read the scan tool will need to go for a boat ride with you/someone to see why the horn is sounding under way/load.