water pump impeller change in genny

sluggo · Post by **sluggo** » Mon Jun 18, 2012 9:25 am

I have an 87 10 meter mid cabin with the orginal onan genny (MCE??) anyway, the genny was working fine, but now it wont pump water, and we tried everything to do so, now we conclude it must be the impellar or that impeller housing is sucking air.

anyway to change the impeller last time we took off the shroud in front (back of the boat, front of the fan belt) , but because the way the genny is set in there, that was hard, and we really couldnt get it all the way off, without cutting it apart. next we unbolted the pump from the manifold (?) and took the pump apart and changed the impeller.
but I swear you dont have to do all of that, that if you come to the back of the genny (front of the boat) you could unsrew the water pump right there and replace it that way. The only problem is that the 1 screw that is at around 5 o'clock we cant get too. The fuel intake line going into the carb is in the way, and evern removing that it is still diffcult to get to.

anyone have any easy way?? thanks in advance!

aaronbocknek · Post by **aaronbocknek** » Tue Jun 19, 2012 6:25 am

the onan mcck was never a DIY set up. ever. this has to be one the most annoying things about this particular generator. having grown up with a kohler in our tri cab, i can see why dad opted out of the onan in favor of our own setup. in short, no. there is no easy way to change the impeller on this beast from wisconsin. the only way that i've been able to do it is remove the pump, swap out the impeller and gasket, jump the belt back onto the pulley and rebolt it. i'm lucky in that my 'shroud' is no longer attached. i've seen this on many an onan.

sluggo · Post by **sluggo** » Tue Jun 19, 2012 9:34 am

aaronbocknek wrote:the onan mcck was never a DIY set up. ever. this has to be one the most annoying things about this particular generator. having grown up with a kohler in our tri cab, i can see why dad opted out of the onan in favor of our own setup. in short, no. there is no easy way to change the impeller on this beast from wisconsin. the only way that i've been able to do it is remove the pump, swap out the impeller and gasket, jump the belt back onto the pulley and rebolt it. i'm lucky in that my 'shroud' is no longer attached. i've seen this on many an onan.

thanks for the imput. you say you have seen this on many onans? what have you seen, the shroud removed or that the pump is hard to change.

can I just go ahead and remove the shroud? thanks

alexander38 · Post by **alexander38** » Wed Jun 20, 2012 5:22 am

sluggo wrote:
aaronbocknek wrote:the onan mcck was never a DIY set up. ever. this has to be one the most annoying things about this particular generator. having grown up with a kohler in our tri cab, i can see why dad opted out of the onan in favor of our own setup. in short, no. there is no easy way to change the impeller on this beast from wisconsin. the only way that i've been able to do it is remove the pump, swap out the impeller and gasket, jump the belt back onto the pulley and rebolt it. i'm lucky in that my 'shroud' is no longer attached. i've seen this on many an onan.
thanks for the imput. you say you have seen this on many onans? what have you seen, the shroud removed or that the pump is hard to change.

can I just go ahead and remove the shroud? thanks

yep, that's what he meant.....changed mine this yr. The next time I'm install a 12v or a 110v pump for cooling and getting rid of the belt driven pump...mine sets side ways in the engine room against fwd bulkhead..

aaronbocknek · Post by **aaronbocknek** » Wed Jun 20, 2012 5:59 am

sluggo wrote:
aaronbocknek wrote:the onan mcck was never a DIY set up. ever. this has to be one the most annoying things about this particular generator. having grown up with a kohler in our tri cab, i can see why dad opted out of the onan in favor of our own setup. in short, no. there is no easy way to change the impeller on this beast from wisconsin. the only way that i've been able to do it is remove the pump, swap out the impeller and gasket, jump the belt back onto the pulley and rebolt it. i'm lucky in that my 'shroud' is no longer attached. i've seen this on many an onan.
thanks for the imput. you say you have seen this on many onans? what have you seen, the shroud removed or that the pump is hard to change.

can I just go ahead and remove the shroud? thanks

sorry for the confusion. i guess it was from the PETSCAN and all the radioactive particles cruising through my system. anyway, what i meant to say was ....i have seen many a shroud permanently removed from the onan gensets. i don't have one on mine, nor did i have one on my 1976 model in my f-32. as for removing the water pump to change an impeller, it's a real pain in the tush to remove and change out. onan never wanted do it yourselfers working on these things. wait till you try to change out the spark plugs. be VERY careful with the rubber boot and the spring. it is not for the faint of heart. it must be done with patience and precision.

aaronbocknek · Post by **aaronbocknek** » Wed Jun 20, 2012 6:11 am

alexander38 wrote:
sluggo wrote:
aaronbocknek wrote:the onan mcck was never a DIY set up. ever. this has to be one the most annoying things about this particular generator. having grown up with a kohler in our tri cab, i can see why dad opted out of the onan in favor of our own setup. in short, no. there is no easy way to change the impeller on this beast from wisconsin. the only way that i've been able to do it is remove the pump, swap out the impeller and gasket, jump the belt back onto the pulley and rebolt it. i'm lucky in that my 'shroud' is no longer attached. i've seen this on many an onan.
thanks for the imput. you say you have seen this on many onans? what have you seen, the shroud removed or that the pump is hard to change.

can I just go ahead and remove the shroud? thanks
yep, that's what he meant.....changed mine this yr. The next time I'm install a 12v or a 110v pump for cooling and getting rid of the belt driven pump...mine sets side ways in the engine room against fwd bulkhead..

tony, how would that particular setup work? just curious. my onan is set up like yours, one in the back of the engine room. i'm not a huge person by any means, (5'7" to be exact) and with the illness, i've actually LOST 2 pounds. even i have trouble squeezing over that onan to change the impeller---it's actually easier to remove the bolts that secure it to the manifold and then release it from the belt----- like i said, onan never intended on DIY folks to work on these things. believe me, if i had the $$$ i would pull it out in an instant and install a kohler or westerbeke.

sluggo · Post by **sluggo** » Wed Jun 20, 2012 10:54 am

aaronbocknek wrote:
alexander38 wrote:
sluggo wrote: thanks for the imput. you say you have seen this on many onans? what have you seen, the shroud removed or that the pump is hard to change.

can I just go ahead and remove the shroud? thanks
yep, that's what he meant.....changed mine this yr. The next time I'm install a 12v or a 110v pump for cooling and getting rid of the belt driven pump...mine sets side ways in the engine room against fwd bulkhead..
tony, how would that particular setup work? just curious. my onan is set up like yours, one in the back of the engine room. i'm not a huge person by any means, (5'7" to be exact) and with the illness, i've actually LOST 2 pounds. even i have trouble squeezing over that onan to change the impeller---it's actually easier to remove the bolts that secure it to the manifold and then release it from the belt----- like i said, onan never intended on DIY folks to work on these things. believe me, if i had the $$$ i would pull it out in an instant and install a kohler or westerbeke.

I would be interested in that setup as well. I checked to see how much a new pump would cost and I am finding them on line for around $1200, ouch!! got to figure something out!