2006 25HP Mercury Outboard- EFI 4 stroke-2006 25HP Mercury Outboard- EFI 4 stroke- motor was cutting

While replacing fuel line from the removable tank to the motor, there are two other issues i identified.

Issue 1- When removing the cowl i found that a wire in a wire harness (believe it is an emissions control unit) apparently shorted out or the insulation rotted and caused a short.

Issue 2- I found a bolt and washer in the bottom of the unit. I suspect it came loose? I need to find a manual or buy one to identify this hardware correctly

The fuel line did cause the issue with fuel flow, not sure if that cause the short with the emissions harness. I want to post some photos so you can share some ideas that contributed to the short.

Thank you in advance!
Aaron

 

Typically harness melting troubles are in the charging circuit. Battery side or voltage regulator failure.

Fuel flow problems wouldn't cause it.

Some guy cranking it too much might. Same with loose bolts.

Probably all caused by hard starting if I have to guess.

But I might change the VR now as a precaution and/or make sure the harness is properly connected first. If the bolt is for the harness; a loose connection motor side can also cuse heat.

 

I looks like i need part #25
84-898101T52

Conversion Kit-Electric Start, 889246a33 for Mercury / Mariner (25 / 30 / Jet 25 Efi / 3 Cylinder 4-Stroke) Engine http://www.marineengine.com/parts/mercury_marine_parts/sn/0R154125/1A25413FK/11848_325

 

Yeah, but you haven't pinned down root cause, so you might fry the new one $$$$$$

 

Do you think moisture in the engine compartment along with too much cranking could have caused the issue?

 

can i wash out the engine compartment? It looks like it will drain out. I have some mud dobbers nest that left sediment in the engine compartment. I was able to get that bolt and washer back in that was floating around at the bottom of the engine compartment under the cowl.

 

No. I don't believe moisture ruined a single wire. It is pure instinct that leads me to believe someone cranked the hell out of the motor and overheated the wire.

So, I would change the $$$ harness and the $ voltage regulator. Put the cover of the engine in the truck and run no cover slow n dry freshwater awhile and verify the harness it not warm/hot. If it is hot; something else is wrong. Otherwise, head back to the truck and run it with the cover. You can also go for a run and check it back at the dock....

 

Call Marysville Marine in Michigan for a better price.

Hope I didn't violate forum rules. No affil.

 

Hello FallGuy. Thank you for the information on Marysville Marine. i will google their information. You said to consider replacing the voltage regulator. Is this the voltage regulator /rectifier?

Starter Motor & Rectifier for Mercury / Mariner (25 / 30 / Jet 25 Efi / 3 Cylinder 4-Stroke) Engine http://www.marineengine.com/parts/mercury_marine_parts/sn/0R154125/1A25413FK/11848_35
Part number 17


I actually ordered the harness with amazon, because i had some 200.00 bucks in points.
https://www.amazon.com/Mercury-Merc...8&qid=1544488174&sr=1-1&keywords=84-898101T52

 

You cn gently wash the compartment as needed where needed

Yes. It looks pretty spendy. I might wait. If the battery dies on you or the voltage doesn't go back into the battery; then buy it.

Example. Start voltage is 12.8V
End voltage engine off after running an hour is 12.6.

Then end voltage after running another hour is 12.4. VR is toast.

If you have been charging the battery a lot; it might be a bad v.r. But start with the harness and feel that wire for heating.

I have had the vr fail on a Merc 50, but it had a service campaign for overheating as it sat on the em.

When you call these guys, ask if there are any service campaigns on the engine. Sometimes an existing problem with the engines is discovered. They don't pay the bill, but correct the issue in revised parts.

Also, look closely at the motor end of the bad wire. It could be cause by corrosion at the contact and the new harness won't fix that issue.