Onan Code 36 troubleshooting

[jonb182t]

I have a 13.5 kw Onan, model MDKBN – 16100114 generator with 1280 hrs in a mikelson 50.  Boat is a 2018.  Purchased from original owner last year.  I continue to have intermittent shut down issues with the generator.  In most situations it shuts down after multiple hours of run time.  Experienced shut downs first at 4 hours and as long as 7.5 hours.  Code is always “36”.   Tested in multiple ways.  Low demand, medium demand and high demand.  With and without the Seakeeper going, with and without ice machine/ refrigeration running in an attempt to isolate whether or not this is a demand or demand spike issue – it doesnt seem to matter what demand I am running or what equipment.  Generator shuts down at troll or on plane.  I never run it very long sitting still so no test yet as to whether it would happen after multiple hours sitting still.   In every situation, the generator will restart without problem.  After restart I have seen it shut down again an hour later or run for 3+ hours until I am finished fishing for the day.   Its nearly impossible to tell how soon after it shuts down that I am checking the coolant temp.  There is no alarm it goes off only a light at the helm that is lit when running.  In a couple of situations I am confident it was only a few minutes after it went off that I noticed and checked the coolant temp – in all situations after shut down I never saw coolant temp above 172 degrees.  Other tests attempted to helped isolate the problem.  At troll with and without the bilge blowers on to determine whether or not we have an airflow issue in the engine bay.  Shuts down either way. On plane running with and without bilge blowers running – shuts down either way. All tests completed with fuel levels at or above 170 gallons in main tank to determine if we have a fuel availability problem underway.  it shut down with 170 gallons and 300+ gallons in the tank. Maintenance completed to date in an effort to fix problem. Diver checked intakes for potential intake restrictions – nothing found Cummins Marine Tech repairs.  temp sensor replaced, heat exchanger cleaned, fuel lift pump replaced, racor cleaned with new o rings, secondary fuel filter replaced, removed and checked all fuel fittings looking for air leak.    I dont need to run the generator all the time but it appears the continual shut down has now severely damaged the seakeeper electronics and pump.    Any assistance or advice on what to test next would be appreciated. Jon      

Topic

[Clark Leighs]

Do your best to describe what the shut down sounds and appears like.

Does the engine shut down abruptly or fast with little or no bumbling.

A fast shutdown with little or no stumbling is likely electrical.

Check electrical connections from and back to the battery.  Don’t just look at them.     Use a DMM to help locate high resistance connections as they can heat up creating even more resistance, enough to cause a shut down

A bumbling, or coughing shutdown is more likely fuel or lack of it. Or it could be air gaining entry to the fuel system.

All fuel line connections tight and DRY. Check all clamp connections. THey do not always weep fuel.    Filters setup properly with snug connections and no weeps. 

 

What kind of filters do you have?

[Gene Fuller]

Code 36 means the engine stopped without being told to do so.  (Not much help.)

I have an MDKAV, not an MDKBN, but the codes are probably the same.

The troubleshooting suggestion are all related to fuel. Restriction, air leaks, etc.

 

[Clark Leighs]

NO one yet?

What does Code 36 mean?   Means nothing to me or others like me without your machine.    Do you have a manual?

 

Generally there are      3 common shutdowns which cause trouble.  There are others of course.

Overheating,  low oil pressure and one other I have forgotten since I don’t have one.

They can be tested by jumpering/bypassing.

What do the dash guages tell you?   

If the engine is running hot it may cross the shutdown threshold when a slightly heavier load is presented or it the seawater it is running in is just a bit to warm.

 

Fill us in on everything on those dash guages.    

 

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