Onan BGE 4K overheating

[tiinytina]

howdy,
    so... for a bit now (we don't use it while running really often)... our genny has been cutting off when stuck in traffic. won't restart.. will crank etc...  then once running down the road with more air around it.. starts and runs fine. I run it while cleaning it after a weekend and if I cut if off when finished, it won't restart. 
   We have changed oil, filters, plugs, wires, points on it last summer.  There was a meece nest in it 2 winters ago, it cranked up and blew out nesting materials from under it.  cleaned that all out. Lower grid is a bit greasy but oil reads fine on levels.
    Wondering if there is a temp switch somewhere or a fan in it? 

Tina

[ibdilbert01]

Sounds like the timing is too advanced.   If the timing is too advanced, they will run hot and be hard to start when warm.    Also check for weak spark when it doesn't want to run, could be a condenser or coil acting up when hot. 

[tiinytina]

checking for a weak spark is impossible due to the location of the genny.. have to unbolt it and swing it down on a jack to a 45 angle to get to plugs/wires etc.... wouldn't want to try to run it that way....  I'll check manuals to find spark advance settings... thanks!

Tina

[DaveVA78Chieftain]

There was a meece nest in it 2 winters ago, it cranked up and blew out nesting materials from under it.  cleaned that all out.

When you say "cleaned that all out" do you mean you pulled all the covers off and made sure nothing was stuck in the cooling vanes around each cylinder?  Air is typically pulled in from the generator end across the engine and expelled out by the blower wheel vanes.  Has to be free flowing all the way across.

Timing - On a BGE as long as the timing marks on the cam and crank gears were properly aligned, then the point adjustment is the only other item that can affect timing (points run off plunger that rides on cam).

Has your mechanic gone through the Cranks But Will Not Start Troubleshooting section of the Repair manual (965-0530)?  They do have a will not start until cool down portion but that is all vaporlock related.

Could be coil as ibdilbert suggested or a electronic part breaking down with heat (control board, Charging Resistor R6, etc.)

Dave

[tiinytina]

Dave - no I only pulled out what flew out when I cranked it over and wiped down the grate under it, used forceps to pull out the shredded napkins the meece had used as nest....  so guessing there is still "stuff" left stuck by grease/oil etc....  I didn't have the manual when that happened to know how to lower the unit (hinged) and take parts off....

I need to remove the cover (which looks to involve pulling the exhaust pipe etc), pull the flywheel and clean the cooling fins.. question is what do I clean them with?  I have the total manual and all it says is "clean the fins"... no diagram, not with what, or how...  guessing a de-greaser?  any suggestions...

Was too hot to be laying on the ground under the RV this weekend... but need to get this done asap so we can use it to get to and from Ohio.... with AC running.. and have no time coming up to deal with it either if I accidently open a can of worms vs open/clean/close etc.... grumble.

Tina

[Froggy1936]

Hi Tina You will have to remove sheetmetal from engine to get all the stuff out ( a shop vac sucking & Blowing) will do if compressed air is not avail. On mine the only ventilation is in the door and it shuts down after a long run time unless run with door tied open  They are very sensitive to heat  I have installed a 110 V fan in the compartment to help with air flow Mine is not a R/V designated unit and was designed for total open air operation   Frank

[DaveVA78Chieftain]

Compressed air, vacuum and a small bottle brush to dislodge anything that is stuck.  Cylinder wall heat would have burnt up most any oil or residue caught up in the fins however there may be residue accumulation preventing airflow.  If I recall, you have a BGE.  Air enters the generator end and is pulled across the entire unit to the blower fan.  With twin cylinders, parts manual I have (Spec F-P now available in Free Manual section) indicates you have a inner shrouds over each side and one at the top that funnel air across the cylinders to the blower housing.  It looks like you may also have an outer weather housing to remove.  Sort of a box inside of a box.  The backside may be a real pain to access if you only swing down the unit.  You may want to sweet talk your mechanic (say smoked brisket Bar-B-Que) into using a transmission jack to lower the unit out of the compartment so you can access everything.  Less risk of messing something up.

Dave

[tiinytina]

Frank - our Genset sits on a rack under the RV... right in back of the driver's side front tire. There is a shield so tire debris doesn't hit it.. but air flow is free and clear around entire unit all of the time (but actually reverse of airflow through genny which is back to front in current configuration). There is no Dash AC.. 4 dogs panting= need genny and AC on for summer running....

Dave - unit is hinged on rack so outer side drops for service (also access door to start it on side of RV).. yes have to take hinge off and lower whole unit out (already have jack to do that) .... Can sweet talk my mechanic friend with lasagna... and or drag him to Ohio for some of my now famous pit roasted yummies (then again having my mechanic trailing us out may be a good thing LOL) ....  residue blow out was oily yet engine holds oil fine, I check it.... so don't think compressed air etc will clean fins.. thought more about a degreaser (simple green/purple power/simply awesome).. but have no blow up of "fins"  or what I will see once the flywheel is pulled.   or if I could possibly damage something using a degreaser.... My luck it would.

Tina

[DaveVA78Chieftain]

Tina,
If by

but have no blow up of "fins"  or what I will see once the flywheel is pulled.

you mean no picture of what to expect, then if you have a BGE unit then download the parts manual in the new generator section I just put together
http://www.classicwinnebagos.com/forum/index.php?page=page560#Onan

If, you have a BGE Spec A-E unit, then send me your email address via private message and I will e-mail you the 965-0232 version.

Dave

[tiinytina]

thanks Dave.. I have an F series, I believe.... and have the parts manual (just forgot as I only had out the service manual that I  bought) (parts and owners manuals are in the binder I keep full of such things).

Tina

[Oz]

Any update on this?

[tiinytina]

no haven't had the time nor patience yet... and its been too freakin cold to be sitting on the ground dealing with it.. LOL

I suspect that the internal cooling fins are probably gummed up and need a good cleaning as my unit is suspended under the rig for all the road stuff to enter... though the genny's airflow is reverse of travel direction so when not on road wind and debris have a clear path to the insides if under about an inch in diameter....

Tina

[DaveVA78Chieftain]

Yep, much to cold!   N:(

Dave