Sensors

2004 350 Mag (Maine lake ski boat)

What sensors would you recommend I replace on this engine as part of off-season maintenance? Only OEM parts will be used. I don't want it being a FW boat to interfere in any recommendation.

If it ain't broke don't fix it, doesn't apply, and I have reasons. I haven't replaced any electrical sensor on this boat since I've own it (5 years?). I have access to a certified merc mechanic to do the [off-season] work, and will do what he says but would like your opinion also.

Removed the outdrive in 2017. I believe I have dry joint exhaust (done nothing to it). Its been tuned-up. Replace anti-siphon, in-line filters. Done nothing to trim. Oil/filters done regularly. Thanks

I didn’t replace any sensors except trim sensors on my last two boats. The trim I wouldn’t do until you get into doing the bellows. It sounds like you are doing the annual maintenance and will likely last many years in fresh water. Exhaust in fresh water I haven’t changed in 35 years on the water.

if you are really looking for something to change do the cap rotor plug wires, plugs and distributor ignition sensor. I keep a spare ignition module (used eBay) in my tool box on the boat those are likely failure points. Other one that comes to mind would be oil pressure switch that supplies power to fuel pump, but again (mean no disrespect) you might be over thinking it. I have followed the same maintenance you outline and my last boat still ran great when I sold it (25 years old) current boat is a 2004 and runs great. Carb rebuild if it is carb?

The most important sensors are oil pressure and water temperature. The sensors themselves don't usually go bad. The connection is the most critical thing. Be sure the connections are tight with no corrosion. Low oil safety switch same thing.

Thanks for the reply. Yes, Ive done the tune-up and also keep a spare starter fuse (solenoid) in my tool box. I'll have to check on the ignition module and the oil switches and the water Temperature, as recommended. The issue is that Maine ski boat weather is so short and if I can't fix it quickly, or can't identify the problem, the marine mechanics are 4 or 5 weeks out. So a little investment in the engine up front goes a long way. Thanks

Based on your rationale in post #4, I'd suggest you invest in the scan tool at a minimum....you can bank the sensors if you want but you'll need that tool (or software on a PC with the adapter) for troubleshooting and verification of any repair - the sensors can be ordered and delivered pretty quick.

The other data that may be worth collecting are the real-time parameters your engine generates while running....nothing like a custom baseline for troubleshooting in the future...

Makomark - excellent point and it's funny you said that because Marineengine.com just sent me (everybody?) a Sierra tool catalog and I thought about starting to buy some OTC brand test tools a little at a time.

BTW - this forum in the past has recommended RINDA type, or brand, scan tool. However, I wonder If I can get a 4 stroke fuel injected scan tool that's a little multpurpose for other powersports? Maybe change adapters?? Thanks

a serial number would help.

serial number: 0W010098 (5.0L,350 MAG, MX 6.2L MPI Sterndrive, EXPartsWeb: 90-884717). This forum has trained me well.

Looking at 4-stroke sleds this week, need that scan tool.

RINDA makes the mercruiser branded tool and they also offer s/w with an adapter kit if you want to go that way. Many other OEMs endorse them as well - that's why they are the benchmark in the marine engine service industry...

I'd suggest calling RINDA and ask what 'expansion options' they have available....there's really nothing 'magic' about them.

This serial number is affected by Service Bulletin MC-2006-002. This service bulletin needs to be addressed. Please complete the required service work regarding this issue.
This recall deals with the alternator wiring. Highly suggest you get this work done.

Sensors, water pressure sensor is the most common to fail. Crank sensor failure is rare. Throttle position sensor failure is rare. TMAP failure is rare.The temp and oil pressure sensors are very rare failures. Don't think your engine uses the cam sensor --- see if any wires are plugged into the back of the distributor. you don't have a distributor ignition sensor. Gear indicator switch failure is rare, but they do sometimes get loose and out of adjustment.

IAC failure is common. Especially if you haven't been changing the IAC muffler every year.

Distributor cap and rotor have had some issues.

If you haven't had your injectors serviced yet, your due.

Thanks I don't think the SB 2006-02 is applicable to me ... I don't have electronic controls but I did attach it to this message for others to take a look.

I'll make note of the the sensors and last year I gave a to minute look for the IAC and moved to something else but this I'll will replace and install as you recommend.

I need to call RINDA today for sensor information.

sab said:

Thanks I don't think the SB 2006-02 is applicable to me ... I don't have electronic controls but I did attach it to this message for others to take a look..

Click to expand...

That is a Mercury outboard bulletin you posted. The MerCruiser bulletin is what you want done.

Yes I noticed but I don't have access to that SB unless somebody can post or IM it. SB 2006-03 is also applicable (plug update, but doesn't have MC code in the SB # like the MC-2006-02 does). It appears somebody is selling a set of SB's on ebay for $26.

I'm not allowed post bulletins. Every time I want to look at them, I must first accept these terms.

This is a recall so a MerCruiser dealer will do the inspection and any needed repairs for free.
Or you could ask whoever you buy your parts from to print you a copy. Every dealer I have worked for has been willing to do this at no charge.

And I'm not recommending you replace any sensors. My personal feeling is there are better places to be proactive than replacing sensors.

Rinda Diacom is worth the extra money. I have never seen a good marine scan tool that covers snow machines also.