What happened to my K341-AQS?

[machinehead323]

I just started my 1650 and drove it only a bout 100 ft. it slowed down like it was out of fuel so i turned it back to the garage. i got it in position and there was a weird noise then the engine died. it turned over like there was no compression. i checked the oil and it was a little low and quite dark. i can spin the engine over by the driveshaft without any resistance. im pretty mechanically inclined and am also a machinist. i have never done small engine work though, except for taking them apart to see how they worked, ask my dad on that one. so where do i start. im guessing its pulling the head to see if the piston is even moving. i do see a valve moving though the carb and spark plug hole. what kinda advice can i get at this point?

[cubs-n-bxrs]

More than likely the weird noise was the rod breaking. Pull the head and see if the piston is moving up and down. Sounds to me like it's time for a rebuild.

[cubby102]

Yea sounds like the rod broke to me. But being and uch low rpm Im hopin for ya it didn't chew to much up. Mine broke at wot and it wasn't pretty

[machinehead323]

well i got the head off. the piston does not move at all. both valves do though. i pushed on the piston lightly and it went down smoothly, does not come back up though. well i guess i have to pull the whole motor and tear it down more. i have the kohler factory manual. i have never done this kinda thing before. i have messed alot with changing transmissions and intakes and such. never rebuilt a motor. i guess its all measurements and torques and such. any advise? im assuming the first thing i need to do is take some pieces apart and get some measurements of where i am at with the bore and if the crank survived. is there a good "how to" out there on this?

[Maxwelhse]

The kohler manual is very comprehensive (with pictures) and should get you through your build with no problems. It's in the technical reference section.

My 149 pulled this same trick about 20 years ago (busted the oil dipper on the rod, then the rod eventually broke).. New rod, rings, and ball hone and she's been running great ever since!

Good luck!

[dvogtvpe]

K series Kohlers have a notoriously weak rods and cranks. cranks wear out of round. clearance gets loose, starts pounding a little harder. dippers break off or the rod starts to gall to the crank, if kohler had gone with the same style Alcoa rod they used in the K361 and made a forged crank like the newer magnums have they would of had something special

[machinehead323]

well i havent got the motor totally out of the frame yet. it looks like i have to take the motor off the rails first which means removing the axel. i have dont that already before so it shouldnt be bad to do. i will do a cradle mod in the process. the piston is for sure oval. there i can see alot of wear towards the valve side, and when i pushed it down i saw it wiggle in the bore. when yall are rebuilding these are you putting them on an engine stand for ease of work. i saw on a website that a regular engine stand can be used with the starter bolt holes. i was wondering if it would be worth it to get the cheap $60 stand for ease of work. i want to clean it all up real good while im at it. is there any good websites on a rebuild, or a how to besides the kholer manual. the pictures are horrible. i have also seen reference to alot of people saying the balance gears can be left out. i have also seen several post that say that the QL series did not have balance gears in them. i must say that the balance gears and the governor give me a little worry. i have never messed with them.

[dvogtvpe]

I've rebuilt engines as small as 3 1/2 horse briggs to a 3000 hp V30 149 Detroit Diesel. I have to say the K series Kohlers are awfully basic. the only major thing you want to be careful of is putting the rod in correctly. oil hole side to the cam and match the marks on the cap to the rod. that's the major error I usually run into when fixing some ones rebuild. I'm pretty sure they took the balance gears out on the quiet line engines since it had rubber mounts

[machinehead323]

well i got me a cheap harbor freight engine stand today. bolted it up to the starter holes. it mounts up pretty nice. being able to flip it around is so nice. well the rod is broke for sure, in about 20 pieces. the crank has some major galling on it. i see 2 small nicks in the side of the journal. it looks like that could be cleaned up with no ill effects. i dont know if there is any scoring on the crank journal jet since there is so much aluminum on there. i have not attempted to get the flywheel off yet. i dont know if i should try and scrape some of teh aluminum off to try and see whats going on or just leave it to the machine shop. i see on brian miller's site that he machines the rods for actual bearings. im guessing this would be steel bearings like a normal rod. seems like that would be alot better than aluminum on a steel crank. the bore is standard size i just did a quick caliper measurement so see. i havent got good numbers with a mic yet. you can see in the pictures i have some nicks at teh very bottom of the bore. 2 of them seem to be in the skirt area. they are below the ring where area. i tried to get my pit mic on it but it was being bothersome. the largest one was around .015 deep. there is one you can see that is right in the ring areas. it seems to be only around .005 deep. if the nick is down below the ring area, would it really mater if it is cleaned up all the way? there is still cross hatch down where most of them are. i am concerned with the one in the ring area. i dont want to bore out more than i have to.

[macman81]

i rebuilt one just like yours last year. had crank ground to match a .o10 rod and cheap hone job and new rings runs like new again.

you dont HAVE TO do a complete rebuild if it wasn't using a ton of oil or making a lot of noise before.