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mongolio

AC 916H w/ K341

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mongolio
I recently had the original Kohler rebuilt bored .020 over, new points, piston, rings, etc.... Anways, after re-installing the motor, I mowed for about 1.5 hrs & it started spitting & sputtering. Call the mechanic who did the work & he thought the valves needed adjusting. Took it back & he found water in the carb but not in the tank & the valve gap looked good. Cleaned the carb & ran the motor for about an hour. He said all was OK. Trailered the tractor home & mowed last week & after approx 2 hrs, it started loosing power & stalled. After a couple of minutes & a few words my kids shouldn't have heard Daddy say, it started back up & was able to nurse it back to the barn. If the valves need to be adjusted, why does it run so good at first? If I adjust them, will it still run as good at start-up? Thanks

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Brettw
I cannot answer your question, but I am all ears if you can find an answer. I have a completely rebuilt K 321 with similar issues. Runs like a champ for anywhere from 20-40 minutes (depends on how long it takes to warm up completely) and then it falls on its face. Starts to run like it is under an extremely heavy load or that it is about to seize. It's not seizing because it will run at idle and start right back up, and there is no evidence of sizing when I pulled everything back apart. I have checked valve clearance, ring gap, points, plug gap. I have been given different ideas and have checked them all, only to get nowhere. I am completely stumped, as are any of those who have offered numerous suggestions, all to no avail. I will keep my eye on this blog and see where it goes. I certainly wish you good luck, even if it is for my own selfish reasons!8D

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Storm7012
quote:
Originally posted by JimDk
Remove Kohler. Install 16 Briggs. Plow snow, mow grass. Be happy.
[img]/club2/attach/JimDk/LastSnowMar19th09rs.jpg[/img]

That would be my vote....

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ardisam
Seems to me, like the carb still needs adjusting. My friend had a Allis 912H, and the motor would do the same thing as your does. Then my uncle ended up with the same tractor. Found out the carb was getting bad, and it was a kohler carb, but it was not for that motor. It was blue in color, and the motor black. So I went ahead bought a reman carb and it ran awesome. I think a reman carb might be the best answer. Ryan-WI Allis Chalmers 916H Allis Chalmers 917H Deutz Allis 1920H Simplicity 7144S

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JimDk
Scott, I live in western PA where our bad weather is caused by cold Michigan air blowing across the lake.:D:D I seem to have better luck with Briggs engines in my working tractors. You need to find which critical component ( spark, gas or compression ) that you are losing when your engine quits. Engines are hard to work on when they are hot, but it might be the only way to find your problem. Let us know when you find it. Good luck, Jim

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mongolio
Jim, I've got family that live in Edinboro, so yeah, I know the winters your talking about. My cousin went out one time for a loaf of bread & came back with a self-propelled snow thrower! Anyways, it's new gas that I'm running thru it. I've got to replace the plug since the one that came with the kit has the threaded on tip that likes to unthread itself & cause some mis-fires. I lightly crimped it to prevent any more mishaps, but will replace anyways. Also, when I took it back after the initial sputter-sputter-bang-bang, they did have to tighen the cylinder head bolts, since apparently one or more had loosened up (after which REALLY LOUD backfire I'm not too sure) but am willing to bet that it didn't help anything either, but they did say that compression wasn't the issue (at least when they checked it ~ cold). Either way, I'm $700.00 into this thing so far this fall & am really hoping that the cold Michigan winter will keep it from overheating too much so I can at least use it to clear the driveway. Thanks again, Scott

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mongolio
Ryan, Thanks for the insight. It's the original carb, which has been cleaned. It does need an adjustment though, since the low idle has been increased so much I no longer need to choke it. No choke, no throttle, truly "turn-key" operation, but I'm so used to full-choke & half-throttle for start up that I keep bogging it down. Anyways, I'm fairly convinced that the valves, once heated are growing longer a bit, which is then cauing me to lose my tappet clearance, which is causing a loss in compression. Do I have this theory right guys? Thanks everybody for your tips, including switching to a Briggs!

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MikeES
Are you sure that it is not running of gas? Is the gas tank vented, remove/loosen the gas cap and try it. How about the gas line filter..partially plugged? How about the fuel pump? If the fuel pump is bad they will slowly run out of gas at full rpm, but run fine at idle. I have by-passed the fuel pump but the Kohler carb does not like it, I have to run with 1/2 choke. The only other thought is that the governor is not operating after warm up??

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fast87
Your fuel pump may be bad. The fuel tank will deliver enough pressure at full tank but with a 1/2 tank not enough to allow the engine to run without choke on. And maybe both valves and pump.

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mongolio
Mike & fast87, Thanks for the help & info on gas &/or pump. This issue has only occurred since the Kohler was rebuilt. It may have leaked & smoked a bit, but always ran tough! Definately worth looking into the filter & pump though. Thanks again,

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sammiefish
I believe that your plug gap must be at .035".... My K241 did not like .020" very much at all... but I have a breakerless ign so check to be sure what yours is calling for... The Kohler fuel pump will run $100 ... there are cheaper alternatives. I could not find the rebuild kit (diaphram) anywhere... and believe me I tried!! You might get lucky and find one on someones shelf. The new pump also does not have the primer lever anymore but it is all plastic... supposedly so as not to conduct heat as much minimizing possibility of vapor lock...??? (yeah right)

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sammiefish
Another thought... Once, I had some bad connections (leaks) in my ignition switch... another time a plug wasnt connecting properly, and yet another time i pulled an engine I ended up pinching a wire on the harness... these all gave intermittent and maddening symptoms not unlike what you are describing... I cant explain why this is happening to you after heating up but maybe do the electrical system troubleshooting steps... in section 8 of the Kohler service manual.. if you have a volt meter you should be able to see if you've got some electrical issue you will find the owner and service manual here if you dont already have it.... http://www.kohlerengines.com/onlinecatalog/serieslanding.htm?series=K-Series

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mongolio
Chris, Thanks for the tips. Any troubleshooting that I can do myself save me $50-$70/hr by not trailering it in to the shop. Thanks again. Scott

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Brettw
I'm still hangin' in the weeds here. So far, the plug gap, check: the coil (replaced) check: Valve tappet clearance, check: Carb (no issues before the rebuild) works well, check: Still warms up and absolutely without warning falls on its face. You'd think it suddenly had to do the work of a 50 horse, it labors, dies, that bad. Idle down, will run and nurse home, but bad enough you're not sure you even want to push it. Cool it off, and ready to tackle the world again. PS did the Briggs 16 thing with another unit. Have to agree, tons of torque and power, no issues. ^

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sammiefish
here is a dumb question.... is your choke wiggling itself to choke or partial choke position without you noticing? When you restart after cooling down do you use the choke knob then putting it back all the way to open... that way you wouldnt notice. I had this happen too... took a week or two to figure out that the knob would come out 1/4" and choke the engine...

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Vassal
I hope this helps more than it confounds: I just had a similar experience with a small Briggs engine in a walk behind mulcher. I convinced myself it was valve clearance (hot) issue. I kept using the machine after the cool-down periods and eventually discovered it appears to be fuel related. It would run hard until fully warmed up and then power falls off, rpm slowly fades, then stalls and no-start. It was just like it ran out of gas. As a matter of fact, it behaved EXACTLY the same when I actually DID RUN IT OUT OF GAS! Fresh fuel and different/no gas cap didn't help. So, on the next hot cycle, I started poking around with the carb, fiddling with the main mix and with the choke setting. I eventually ended up with what I believe was a slighltly LEANER setting on the main jet and A LOT of choke (3/4 +). It now runs strong for as long as I care to use it after adjusting and choking carb. I'm not saying this is right, it's just how it is:( BTW, this engine ran fine prior to this day and makes me think the dusty/crusty environment (leaf mulching) may have caused this problem. This is not my machine, so I have not gotten a chance to really get after this problem, but I did notice that PO had replaced the carb recently, it's the only new looking piece on the thing. All that said, there' still a chance the richer mixture is compensating for another underlying problem. My $.02 worth, spend accordingly.

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LesH
I would replace the coil--- I went with the 12 volt coil with an internal resistor from O'Reillys auto parts chain....price was $23. (my local dealer garden tractor dealer wanted $49)and never have had any more stalling after engine warm up.

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mongolio
Thanks for the additional info guys. Chris, I don't think the choke is working itself out, but will check this weekend, barring rain. As it is now, the low idle is set so high I can't use the choke, it bogs is down. The last time I used it, was able to restart with a little choke & A LOT of luck to restart & drive it to the barn. After a few minutes to cool down (me, not the tractor) it started right up again with no choke or throttle & I was able to throttle up to full & it sounded great. The 1st time it took hours to restart, the 2nd time, a matter of minuts & a few well placed "suggestions" & it re-started. By the way, after disengaging the hydro, have you ever tried pushing an 800lb garden tractor up a slight grade? Thank God it re-fired. It's not fun at all!

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pungo
Take the hydro belt off and run it till hot to see if the bogging down starts.(Hydro drive pulley shot). Some other thoughts. Grunge in fuel tank breaking loose and repeatedly ruining new filters. The fuel line is too long, too narrow ID or located near a hot spot. Fuel line is cheap and sucking closed. Tank has a nice layer of water in it. Choke cable installed backwards. Crankshaft bent/warped. Governor shaft bushing shot. Bad batch of new coils from same Supplier. Breather hose vibrating/rotating to intefere with linkage. An intermittent ground from frayed wiring somewhere in harness. A shot bronze bushing somewhere in driveline heating up and seizing. A cheap headgasket or warped head. Oil/lubrication system not delivering properly.

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Willy
If I paid 700 buck to have an engine overhauled you can bet the yardbirds that did the work would be the ones trouble shooting the problem. Why not make them do it right?

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sbull78
holy crap!! i have a k301 for my 7012 in the shop getting resleeved and the whole works...i hope it doesn't turn out like this nightmare....i had a 16 horse twin that would do this..it ended up being about 4 different things wrong with it and after a lot of evenings and curse words i finally figured it out...good luck

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