I have motor out and appart. I see warnings about replacing both pistons and rods even if you only need 1. Will this really cause a problem? Also the governer ball spacer is split. Cant find a new one. You have to purchase new gear assembly? Wow what did i get myself into? Alot of $ to rebuild this motor. Is it worth it??
Help broken jd 318 onan
JD 318 Blew Up 
:fing20: My 318 decided to throw a rod a couple weeks ago. I probably deserve it. Not great on the oil changes. I also abuse the mower on a regular basis. What a work horse.......
:fing20: My 318 decided to throw a rod a couple weeks ago. I probably deserve it. Not great on the oil changes. I also abuse the mower on a regular basis. What a work horse.......1 - 13 of 13 Posts
I think it all depends on how bad the engine is... The Onan's price to repair is getting more and more expensive. I know a few people that chose to repower their 318s instead of working on the Onans, so in their cases, it was not worth repairing the Onan.
Yes their a little pricy on parts but a good rebuild is worth it. Bet next time you keep that oil changed. Up there in your neck of the woods are a lot of JDs for some reason and fairly cheep too , you may find a replacement engine. just send the old one down here and let me play with it
ree85.
i stock an extensive selection of used onan parts.
call 651 437 2826 this afternoon central time.
thank you. boomer
i stock an extensive selection of used onan parts.
call 651 437 2826 this afternoon central time.
thank you. boomer
ree85, as you stated that engine took many years of "abuse" and did wonders for you. If you invest in it, it is likely it'll do the same thing again! However you won't get a warranty with it like you would a repower.
Thanks for the advice guys. I think I will attempt to repair the existing motor as it did serve me well for the last 14 years i owned it. I bet it didnt get the oil changed a half dosen times over the last 14 years. Supprising enough the crank and block measure up good. I cant believe it, piston bores within .0015 top to bottom and round within .001. Crank measures within .0005 round on all fits. I am having trouble finding a replacement piston and rod. I would like to only replace the broken parts , rings and bearings. The spacer for the flyballs is also a problem as I would like to reuse the cam and gears. I cant find a spacer and will probably end up making one. Im thinking it should be a press fit to the hub so it spins with the crank and gear. I was thinking of making it out of bronze. Any suggestions? I dont want to use plastic. I heard someone say the early ones were steel. Im guessing they were Cast iron if they had problems with them breaking. I hate to put a old one in even if it is not cracked now. Im afraid it will crack and cause the same problem again. Blown motor from runaway RPMs. Any one ever made one and did it work?
i guess i do not know WHY you did not respond to my post
from earlier today.
i have all the parts that you need in stock???
thank you . boomer
from earlier today.
i have all the parts that you need in stock???
thank you . boomer
I think .0005 is .0002 over the tolerance for the crank,will tend to rattle,check with boomer for parts,you won't be dissapointed in the re-build and use JD 30 wt oil afterwords.Onan parts.com has a good list of parts and discusses the rods in detail,but the pistons have to be matched in the casting numbers to be the same weight.
Uh, Biker, I think you misinterpreted his measurement. Check the decimal location. His is only 1/2 a thousandths out, not 5 thousandths.
You are right,I thought that was a lot,I have one the is 7 th under and it makes a terrible noise so it is out now,trying to figure out what I want to do with it.Just last year I put new valve guides and rings in it but now the crank needs turned.
Recieved parts yesterday. Everything looks great. Assembly will get started this weekend. I will let you know how it goes. Thanks boomers_influence, saved me alot of money getting my 318 with onan engine running again.
1 - 13 of 13 Posts
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