Yamaha OX66 Oil tank sensor Failure Diagnostic

Piston picture at end.

[@pauldavis1465]

This was a really good video. Currently I am having the same issue with the same cylinder… I am at a loss thorough as what was the cause of this #2 cylinder going bad in the first place… as I said I’m having the EXACT same issue, no warning lights, limp mode or buzzer till it was to late… immediat inspection revealed no oil in main but full reserve tank, got home pulled the [lugs and cylinder 2 was fried and gap completely closed… was almost spooky seeing it verbatim but thank you all the same for your time… now if I just knew what it was that made only #2 blow I may be able to remedy the problem correctly and fully

[@jamesrahn8339]

This helped me out a lot. Thanks for posting

[@hotheadzmarine]

I'm glad it helped. I know it's not the best video but thank you so much for your kind words. God bless you

[@jamesrahn8339]

It was very thorough and explained a lot... very good video!

[@chunkyfather29]

Man, great video. Currently working same issue on customer boat. Pain in ass

[@toasterj3643]

also the customer put the oil filter on the wrong way . arrow goes to the pump

[@carlhazelton1077]

Thanks! Good info

[@michaeljacobs2570]

Nice job diagnosing..I have an older 175..89' and the engine oil tank gets half way empty then the hot horn and limp mode..I used a jumper lead on the pump on the Tank reservoir and it works..So in conclusion this system can become an Achilles heal.What surprises me is why the client filled filled both tanks after the fact..At some point there was no oil transfer from the engine oil tank and the computer failed..Initially a dry cylinder..and bad fuel injector seemed the culprit..My manual switch isn't working either so I'm not getting voltage somewhere..(harness) is there a fuse on the engine end..?

[@revolutionmarine5693]

The first thing I do is a compression and spark test. If compression is low pull the heads and the condition the piston is in normally tells a lot of the story. If it's blown apart with little cylinder scoring then it's likely a defective piston. If the piston is melted it ran lean of fuel. The head cylinder chamber will also have no carbon left or very little. If you feel oil on the sleeve then it definitely wasn't an oil issue.

[@Hajsansvejsan]

Can I get hold of oversized cylinder sleeve to these engines, and if where can I find them? The engine block has cracked, so I need a sleeve that is thicker because I have to weld and process the block that's hold the sleeve. Grateful for help

[@iorans.thiago1288]

Hello. i have a similar yamaha. the same problem happened in the same cylinder. we were unable to diagnose the problem. it may be a broken ring, injector clogged at some point, ignition coil with intermittent problem or at a specific rpm. test in an ociloscope. In your opinion, what must have been the cause of the problem?

[@DirtMcGert29054]

I had my number 2 rod bearing fail , and the wrist pin was sloppy , all I can figure is the recirc port by the reed valves was plugged , even with the bad rod bearing compression was in spec ' 109 (it was the lowest best was 120) , 947 hours 01 2.6L , sent injectors off they came back good , one had less flow that the rest but it wasn't #2 , just got it rebuilt and back together just need to hook up a few. Ore wires

[@hotheadzmarine]

🙏

[@TheBassmasterwi]

I have the same motor and same cylinder that had 0 compression. No one local would even touch it. They all just said to buy a refurbished powerhead

[@hotheadzmarine]

The real problem is why it failed. Replacing the powered will take care of the 0 but guess what will happen again. BOOM 💥 We are in process of phasing out repairs on many many 2 stroke outboard engines. I would recommend buying a new 4 stroke. Your never gonna be happy and enjoy your boat with any reliability or confidence until you do. Get a loan if needed but do yourself a favor. Go 4 stroke. Mercury. They have the engines these days.

[@labiadh_chokri]

Nice video, just use the diagnostic tools to see the state of the different oil level sensors .

[@DirtMcGert29054]

I had one where the flat wire going to the remote tank failed

[@jessikafulford4999]

wheres the best place to get a yamaha 1250 oil sending unit

[@hotheadzmarine]

Boats.net

[@leodanescalona9417]

I have Yamaha 0x66 computer 225 hp 450

[@JCASTELLUCCIOJR]

Seems as though...WHOMEVER installed the oil-reservoir filter incorrectly = IS RESPONSIBLE for any/all oil related damages!!! I am not a mechanic---just my opinion!

[@hotheadzmarine]

That's was just during testing and was corrected immediately.

[@michaeljacobs2570]

Both reservoir tanks being full when the on board(boat) pump wasint working suggest the owner knew something wasint right..but in their defense the alarm horn wasint activating..to alert him or her of the engine side tank going low..diagnosing can be challenging..The owner may have known the main tank wasint transversing and ran it low.. We don't know..Owning a boat can be expensive...People will throw their mechanic under the bus when they are panicked and desperate..being respectful and truthful can eliminate bad outcomes from the get go..The motor side tank going low was an issue and not the result of the mechanic or the client..Just be honest..

[@chunkyfather29]

Even when installed wrong. Filter is made to be idiot proof. It will still pump

[@88grady56]

what's the deal at 17:40 ? anyone see this?

[@hotheadzmarine]

it was a relation to the word working.