Oil Change and a Diagnostic on engines

[David Martin]

Hey guys I thought the new folks might want to do future diagnostic so I'll pass along a little knowledge that might help someone down the road/lake. My boat is running rich due to excessive idling and Blackstone confirmed this in the oil. Blackstone also confirmed low metal were and not to worry just change the oil. My oil was a 5 on fuel contamination their test the average of 2.5 as a high on all oils they see. So I just changed oil and wanted to share a diagnostic approach that will help most people.

First the best engine diagnostic STARTS at a good PLUG read nothing will give you more info than this as to engine health. Hear is my Port and Starboard read. The Starboard reads top left to right as you can see all plugs read rich but the number 2 and 4 plug are at lease twice as rich. Post read is left to right and all plugs read rich with the #2 as a total off the scale rich. Now this info along with the oil analyses is starting to add up.

Now a lot of things can cause a overly rich cylinder 1 broken ring , bad valve seats, both of these lower cylinder pressure causing poor flame fronts, bad coil packs also poor flame fronts, bad computer, wiring and last bad injectors(my fav so far)........that leads to the SECOND diagnostic test COMPRESSION TEST this test eliminates a lot of the above possible problems. My Starboard engine 210,210,207,210 PSI, looks excellent to me. Port 210,210 205,203 PSI, Nothing wrongs with these numbers.... so long broken rings,valve seat leaks....this test leaves coil packs, injectors computer EMC and wiring.

Not that's where I stopped and since Blackstone Lab gave me a low metal for my engine and they Start quick and run smooth I WILL NOT BE PULLING THE ENGINES out of service but will correct the cylinders on the naughty list soon.

Next week out comes the multimeter/omh meter to complete the diagnostic of the coils, injectors, wiring to computer(emc)from both of the remaining parts to find out which one will be left standing as the PROBLEM CHILD now all these readings will get written down in my service manual giving me a great snap shot for future reference.

HOPE THIS HELPS A LITTLE in you future diagnostic approach ......... I never look for what's wrong I test for what is good and that usually leaves you with the problem. Now my Gut says (injector) corrosion......... I feel electronically the injectors and coils will be within specks because I purchased the boat last year its was a 2013 with 23 hours on the clock, it sat most of its life (none use is a recipe for corrosion) the 4 injector spray holes and spray needles are my best guess....but the meter will tell.

Sorry for the book!

 

[David Martin]

Hey guys hear is some test data, picts of ground wires, injector rail and my baby concerning my fuel rich oil and 3 black plugs and 8 rich plug read. First leave comment if you think I am calling it quits too soon. The black plugs were just corroded partially blocked injectors. Hear are the clues for corrosion and not dirt clog. The injector filter screens were perfectly clean absolutely no dirt or debris at all. That leaves corrosion inside the injector blocking the 4 spray ports and yes those 3 streamed and had a lousy mist. Back flushed all injectors and cleaned in flow direction until I got a great spray pattern all looked great and matched after cleaning..........one problem solved.

Now on to the 8 rich injectors it important to remember both engine are running the same, quick starts cold or hot and performance 7550RMP at 52.3 Mph. Non tested items that can effect an engine richness are fuel pumps, Temp sensors, (4 per engine), clogged air filters(both are clean)MAP, ect ect..........I not buying into the odds of parts drifting out of normal on 2 engines at the same time and falling below normal AT THE SAME TIME AND AT THE SAME RATE not buying what the odds are selling. The numbers below are Coils, EMC computer. injectors, pick up coil.......nothing is jumping out saying look at me. Another point...... each engine has 3 ground connectors connecting 26 ground wire per engine(separate system for each engine) so should I buy that corrosion has entered a connector on both engines and affected only the circuit's that only affect richness of injector and BY PASS 52 OTHER systems.......NOT BUYING what THOES ODDS are selling.

Diagnoses over.... Conclusion 3 injectors fixed and hopefully some of the fuel% will drop in the oil not expecting all to be gone I still idle more than 50% of my hours AND Yamaha mapped a slightly rich fuel curve......there is an old quote that matches this scenario ( run an engine slightly rich and that motor will last a long time, run an engine slightly lean and YOU WILL BE BUYING A NEW ENGINE). Engine is running as designed rich and cool 140 degrees thermostats.

I do not feel I wasted my time....... I learned a lot about the electrical systems and grounding systems for the future when I do have a real problem I have a lot of reference number to help speed up diagnostics.

Thanks I have read a lot of posts hear and learned a lot from of you guys that has help me in my quest in understanding these systems. Sorry for the book!!!!

 

[Can0n11]

Nice work. Do you have a way to test and clean your plugs?

 

[Zizzou 192]

Yup, the 1.8 engines run rich, eating spark plugs like a 2 stroke and hard starting after idling. Nobody has ever denied that. Nice to see it confirmed in an oil test.

 

[David Martin]

Cleaning is just a little carb cleaner and a rag...........If that won't do it a soft tooth brush helps..........as for the testing..... a ohm meter from the center electrode to the plug cap. Compare all plugs looking for the one that stands out different, or maybe if several are off the rule of thumb is replace at 5k ohm or above. As plugs age the resistant/ohm rises. A good way to get max life is ohm a new plug then you have a great reference number for comparison later on the old plug.

Plus most brands and construction like Platinum/copper/iridium will all had different ohm so that reference number becomes important.