Trojan Boat Forum

my mcck onan genny shuts down after about an hr or so of running. We worked to get this thing going again, and seemed to have everything right. It pumps good raw water, I replaced the thermal cutoff switch with a new one. Cleaned up the carb real good, and had it running like a top. But after about an hr hr and half it shut it self down, and would not restart. to me it sounds like that thermal cutoff switch, but really I dont know. any other thoughts??

Clean out the riser

Back to basics; check for spark and fuel. If no spark, could be ignition issue or cooling issue as Paul suggests. Check and see if you're getting fuel to the carb when you crank her over. If your fuel tank is around 1/4 full, that's most likely your problem as the pick-up for the genny doesn't go into the tank as far as the engine pick-ups do to ensure you don't use up all the fuel on the hook and have enough for the engines to get you home.

aaronbocknek wrote:depending on water conditions, i do a mary kate on/off acid flush of the cooling system every other month. what this does is clear all the schmutz and critters from the system, and, since my onan is raw water cooled, it's of the utmost importance. get a spare one or two foot length of 1/2 inch hose and attach it to the cooling pump of the genset. wear gloves and eye glasses as this is acid. pour some on/off into the hose via funnel. use the controller to bump some of the solution into the cooling system. keep doing this until you've used an entire bottle. let the solution sit for about 30 minutes. reconnect the cooling hose to the seacock, start her up, and watch the crud purge from the system. you might also want to check the thermostats. these little buggers are just .5'' in diameter and can get crudded up pretty easily and are often ignored. if you have problems locating a thermostat service kit, thermostats and gaskets, cobe marine here in maryland has them. if you do change out the thermostats, take a little on/off and pour it into the 3 holes to clear out any buildup. the on/off flush really works.
you might also want to check the thru hull under the boat. when my boat was painted, the yahoos painted right over all the holes of the round external strainer. i spent about an hour opening these up again using a drill bit as a hole punch. hope this helps.
aaron in baltimore

Thanks man, now i have one more thing added to my todo list for when i get back

trying to find the mmck thermal cutoff switch as well as min blew out.... expensive little things, the only ones i found were 250+

Just thought i would add one thing i found in my boat this week. If the sentry system is turned on "for dual power" my generator will not start, have to have this turned off to start the generator.

Not sure if its the same on your end but maybe a quick check.

Vitaliy wrote:

aaronbocknek wrote:depending on water conditions, i do a mary kate on/off acid flush of the cooling system every other month. what this does is clear all the schmutz and critters from the system, and, since my onan is raw water cooled, it's of the utmost importance. get a spare one or two foot length of 1/2 inch hose and attach it to the cooling pump of the genset. wear gloves and eye glasses as this is acid. pour some on/off into the hose via funnel. use the controller to bump some of the solution into the cooling system. keep doing this until you've used an entire bottle. let the solution sit for about 30 minutes. reconnect the cooling hose to the seacock, start her up, and watch the crud purge from the system. you might also want to check the thermostats. these little buggers are just .5'' in diameter and can get crudded up pretty easily and are often ignored. if you have problems locating a thermostat service kit, thermostats and gaskets, cobe marine here in maryland has them. if you do change out the thermostats, take a little on/off and pour it into the 3 holes to clear out any buildup. the on/off flush really works.
you might also want to check the thru hull under the boat. when my boat was painted, the yahoos painted right over all the holes of the round external strainer. i spent about an hour opening these up again using a drill bit as a hole punch. hope this helps.
aaron in baltimore

Thanks man, now i have one more thing added to my todo list for when i get back

trying to find the mmck thermal cutoff switch as well as min blew out.... expensive little things, the only ones i found were 250+

I thought i paid around $60 for mine, I just searched the onan part number and got some hits, the guys on here may sell them.

it would be nice to know that part number as its not stamped onto the part itself

Vitaliy wrote:it would be nice to know that part number as its not stamped onto the part itself

hi there, and thanks for using ''ASK THE HEBREW''. only too happy to be of assistance. the onan part you are looking for is 0309-0420. make sure your exhaust elbow has the flat area to mount this. here is a place where it may be purchased for $42.50.

http://onanparts.com/index.php?main_pag ... cts_id=532

if you need a new wire harness, that is part # 0338-1413, and may be purchased at the following for around 25 bucks.

http://www.generator-parts.com/generaco ... t=37236470

thanks for using, ASK THE HEBREW!!

sorry, my attempt at humor on this day.

aaron in baltimore

much appreciated buddy

Vitaliy wrote:much appreciated buddy

no worries. do you have any of the manuals? if not, i might be able to send them to you, as i have the pdf for the parts, operators, and service manuals for the 'cck' genset.

aaron

is there a difference between the cck and the mcck? and a manual would be awesome man

Vitaliy wrote:is there a difference between the cck and the mcck? and a manual would be awesome man

sorry for the confusion. the 'engine type' is the cck. onan used the same engines for rv and marine applications, thus the MCCK denotes 'marine' and RCCK denotes 'rv'. all i need is your email addy and i can try to see if google chorme mail will allow me to send the pdf manuals to you. sometimes it shuts it out due to size.
aaron

Test for spark, if none could be the coil breaking down with heat, also if no spark check points.