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Diagnostic Tool

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    Diagnostic Tool

    Can someone let me know what is the best diagnostic tool for the Mercruiser 260 MPI/B3 5.0L? Came across the Tech Mate Pro , by Rinda, but seems a little pricey at $500.00. Not sure if there is one less expensive that will do the same thing.
    Last edited by Jim_Gandee; 01-14-2021, 06:16 AM.

    There is no better tool than a multimeter, a DVA (digital voltage adapter), a digital tachometer adapter and an electrical drawing.

    The reason I say this is because If it is like the automotive diagnostic tools, it is a only going to give you a list of possibilities. And then what? Now you have 10 etc., possibilities and still no way to find the problem without the....wait for it......a multimeter lol

    Unless you buy the computer version of a diagnostic tool (which only dealers can buy from the manuf.), I don't think any of those handheld tools will show you specific details about anything.


      Thank you! The problem is I think it is an oxygen sensor or other sensor. I am not a mechanic and not sure how you would test one of these with a multimeter. I was told that at least a Diagnostic tool would give you a specific code, which you could then google and get the correct sensor. I may be all wrong.

      Thanks again for the advise,



        If your Engine is Smart Craft enabled, you may want to look at the Mercury VesselView Mobile Module. It will give you code and lots more for only $275. Works with you Phone or tablet.

        Connect with your engine like never before VesselView Mobile wirelessly connects your engine to your mobile device, giving you unique insights and details into your Mercury engine*. 

        Here is good video of what it does.

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          I've never worked on an electronically-controlled boat engine; but I have worked on electronically-controlled car and motorcycle engines. In my opinion a good scan tool is a must for troubleshooting an electronically controlled engine. The tool will provide a starting point for component troubleshooting. Then, other tools like a good digital multi-meter can be used to continue troubleshooting.
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            Pay a bit more, get the Rinda...

            Has so much more capabilities.
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              I'll admit that for most people who are not familiar with how boat engines and their electrical systems work, a scan tool may be a better option.

              Like Waterdog posted, if that tool will give you "specific" codes leading directly to the problem component, that would be better than the one's I've seen that only give you a list of possibilities.

              Most engines I've worked on here are not completely computer controlled like most models from 2004 and up roughly. So there is no magic device to see what the motor is doing.

              And I'll restate, any good repair manual for your engine will give you ALL the test to check just about every component on the engine, including the O2 sensor. I'm just too old school I guess because I like to understand what the issue is as well as what is causing the issue.

              I'll give you a real life example of why many of those tools won't help....sometimes

              I worked on a motor that an issue with spark not being on one coil. When I tested it with my meter you could see that the one particular coils meter readings seemed fine, the trigger was fine and so was the switchbox but the coil was not firing. So I had customer order a new one, and also told him he needed to add a missing mounting bolt on the plate that the coils are mounted/grounded to. New coil came in, went down and installed it. Didn't notice the missing bolt was still missing until later. Installed coil, guess what, coil now had intermittent firing. Started wiggling wires around etc and could see the coil fire then not and on and on etc. Had customer find a bolt, installed the bolt, coil fired right up and no more intermittent firing.

              The coils have 2 mounting holes, one hole mounted it to plate and 2nd hole went thru plate thru coil then to engine block.

              Now you'd think since coil was originally mounted to plate with 1 bolt and the plate grounded to engine thru other bolts the entire plate/coils would be grounded. Not exactly. The missing bolt was causing that 1 coil to intermittently fire due to engine vibration etc.

              The point is, if a scan tool could detect a bad coil it would only be able to tell you that coil was bad, so you replace it. In the scenario above, that coils would have thrown an error code again and what would most people do? Send it back stating the coil was bad.. Problem is you never find out why the coil "was" bad, which in reality it was never bad to begin with.

              Ok guys, just thought I'd share that story. Believe it or not, I'd say probably 25% of all electrical issues on a boat are due to bad grounds/bad wiring! And there are a lot of boat marinas and techs that seem to think it's ok to start replacing components till they fix the problem instead of finding the problem first, then replace that component. Something I like to call... Doing your job!