WE ARE NOW AT A NEW HOME!
| Welcome to Only Cub Cadets!. We hope you enjoy your visit. You're currently viewing our forum as a guest. This means you are limited to certain areas of the board and there are some features you can't use. If you join our community, you'll be able to access member-only sections, and use many member-only features such as customizing your profile, sending personal messages, and voting in polls. Registration is simple, fast, and completely free. Join our community! If you're already a member please log in to your account to access all of our features: |
- Pages:
- 1
- 2
| Same old problem; She still bogs down at WOT | |
|---|---|
| Topic Started: Mar 2 2009, 05:21 PM (395 Views) | |
| weaverama | Mar 2 2009, 05:21 PM Post #1 |
|
Folks, this problem has me stymied so take a minute to read through this. I have put up with this for many months now. If we can't fix it this time, it may have to go into the shop. The K241 on my 1000 barely ran when I bought it last year. It backfired badly and had no power. With your help I got it running fairly well but it has never really ran great. Here's what it took to get running. The head came off, it was de-carbed, new gasket, new breather, adjusted valves, new plug gapped at .035, new points at .020, oil changed to correct level, gas tank removed cleaned and filled with fresh gas. Carb was cleaned and adjusted as per the service manual. She ran OK for a number of months but I never ran her that much or that hard. Over the summer I was pushing some dirt around with the blade and the Kohler would start to run poorly at high RPM's, there would be a loss of power and eventually it would start to backfire. A fresh set of points seemed to help. Today it started again. It feels like the engine just would not rev to 3600 rpm's. (I have no tach) The engine starts to make a funny sound as it approaches max rpm, almost like it is sucking wind, (hard to describe). It sounds like it wants to rev up but then it almost sounds like a load is put on it. The governor starts to surge and it feels like it is starving for fuel or air and after a minute or two it starts to backfire. I re-gapped the points which only had 2 hours on them, they did not look clean so I gave them a light buff with 220 sandpaper. When this did not help I put on a new condensor and still no help. I re-gapped the points down to 0.19 and this seemed to help, at least it stopped the backfiring but she still feels like it is "suffocating" at WOT. I should let you know that when it did backfire you could see a noticeable change in the spark pattern jumping the point contacts. (Not sure if this means anything) I just finished plowing the driveway and she will push all day at three-quarter throttle but I know it can run better. Here are the few things I've been thinking about that might be important: The float bowl has not been adjusted. Nor was the carb dismantled completely last year but it was sure blown out good with Gumout. Every nook and cranny that I could get to. When I de-carbed the head and valves, I did a pressure test by blowing 125 psi up through the valve adjustment ports. The valves leaked, but wouldn't most anything with 125 psi blowing up your skirt? Of should they have held? Don't discount that I am a novice at this stuff. If I should go back and do something again let me know. What kinda baffles me is that while it never runs great at WOT it takes a good hour or so for it to start the backfiring business. Thought it was the points getting fried hence the new condensor but that does not seem to be the problem. I just don't know. Tell me if I have missed something. If y'all start talking about Ohms of resistance and stuff and can't talk me off the ledge, it might be time for the shop. Thanks everyone. Rich |
 |
 
|
| Matt G. | Mar 2 2009, 07:17 PM Post #2 |
|
I think your valves should hold 125 psi. However, your method of testing them doesn't make any sense. If by "valve adjustment ports" you mean the breather cover, you put 125 psi into the crankcase and NOT the combustion chamber, so the air was probably leaking up through the rings and out an open valve. Was the crankshaft positioned such that both valves were closed? I'd apply 125 psi through the spark plug hole with the piston at top dead center (TDC) and see if you still have air coming out of the exhaust and carb. (Basically, you need to perform a crude 'leakdown test') If you do, it's time to pull the head and remove the valves and see if they (and the seats) are worn. I had an 86 that would start hard and run like crap at WOT. I replaced and rebuilt the carb and changed the whole ignition system to no avail. It made the same weird noises that you are describing. When I removed the valves, I found out that both were completely worn out on the seating surface. The seats were fine. I bought 2 new valves, ground and installed them, and it fixed the problem. I would also make sure that your carb float is adjusted per the manual (which you better have by now :) ). The backfiring may be a valve sticking, which is another problem on top of worn valves. I'd check the guides while you are in there too... Here's a place with reasonably-priced aftermarket and OEM parts: http://tewarehouse.com/ I have purchased from them several times. |
|
|
|
| weaverama | Mar 2 2009, 08:00 PM Post #3 |
|
Matt, Thanks for the ideas. Forgive my terminology, but yes I did the test by removing the breather cover. What I did was stick the trigger nozzle of my air compressor in there with a rag wrapped around it to hold the compression in. I put a little soapy water on the valves, with the head off of course, and when I applied compressed air, there were bubbles coming from around the edges of the valves. Yes, both valves were closed. I thought I read somewhere that this was the correct procedure for testing valve seats, did not know it was open to the crankcase. But in any case, something got pressurised and I got bubbles around the seats. So it might be the valves and carb float...anybody else? |
|
|
|
| Matt G. | Mar 2 2009, 08:20 PM Post #4 |
|
That method of testing valve seats doesn't make any sense to me, as the valves are never placed in that situation when the engine is running...What you tested was the sealing ability of the guides, which doesn't mean anything. I suspect your valves are bad, as there's no way you're actually applying 125 psi that way, and you're getting bubbles when the air could just take the path of least resistance out the exhaust and carb venturi. BTW, if the engine is between the exhaust and intake stroke, (at TDC) the valves will rock rise up and down alternately if you wiggle the crank, and therefore neither one is sealing. However, if it's at the top of the compression stroke at TDC, both valves will seal. The latter is what you need for a leakdown test. |
|
|
|
| Diz Jr. | Mar 2 2009, 09:33 PM Post #5 |
|
Before you go tearing the engine apart i would thoroughly clean the carbureator, if it is really gummed up just spraying it out might not get it all. My 149 had been setting for several years and was really varnished up bad. I took it off and sprayed carb cleaner through every thing i could, It would start and run then, but not great. like you said it ran like it was starving for fuel or air. I took it off again and completly disassembled it. Even the little round plugs were removed so i could clean the tiny little holes behind them. You have to be sure to get the right carb kit that has all the parts you will need. But it really made a huge difference in how mine runs. Just my :TwoCents |
|
|
|
| Skip | Mar 2 2009, 10:53 PM Post #6 |
|
Get into that carb. I would tear it down soak it for a good while and look at the throtal shaft and bushing. You can rebuild a carb with a kit or you can rebuild it shaft bushing new buterflys ect. I had one done like that and it runs like a dream and befor it did the same thing at full throtal and or with a load on the eng. And be sure your float is set right.
|
|
|
|
| Yosemite Sam | Mar 3 2009, 12:31 AM Post #7 |
|
A very wise man once told me that "most carburetor problems are electrical". Another told me "Start with the easy stuff first". Does it seem to get hot? First thing I would do is remove the high speed needle from the carb. and check the tip to make sure it's not bent, probably most importantly check the little holes in the sides of it's shaft, get a tiny piece of wire and clean them out, try to run the wire up through the inside of the needle through the holes in the side, then blow it out really good, then make SURE that air can easily go in one set of holes and come out the other, while you are looking at the carb check the throttle shaft for wear if the shaft hole is worn you will never get it run right, it will seem like one thing is wrong one time and something else the next. Check the coil and make sure that it is a 12 volt coil with an internal resistor. If a coil reads "12 VOLTS" on its casing, then it has a built-in resistor, if it doesn't say "12 volts" then it probably isn't, and should either be replaced or have a ballast resistor installed, to prevent it from putting too much voltage through the primary circuit and ignition points. Then I would try to set the points with a timing light, it is possible that the cam is worn where the push rod for the points is, or the rod itself could be worn, and if you haven't already, replace the condenser. If none of these things seem to work for you then go here, http://gardentractorpullingtips.com/ignition.htm and read what this guy says, you'll be glad you did. Edited by Yosemite Sam, Mar 3 2009, 12:42 AM.
|
|
|
|
| weaverama | Mar 3 2009, 08:54 AM Post #8 |
|
Ok guys, I will start simple and pull the carb and do a rebuild. If I recall though the throttle shaft and bushings were within tolerance the last time I had it off. The coil is marked 12 Volt. Then I will start to think about pulling the head and checking valves. Question: I don't really want to mess with valves seats cuz they're beyond my 3 T's (Time, Tools and Talent) If they look to be OK, is it enough install new valves and lap them in using the old seats??? I have a backup plan that might become a reality. I have a chance to buy an older 12hp for $200 with 8 hours run time since a total rebuild. It is from a 12X series so it is a bit different than the Quietline block, i.e., exhaust and shrouds. Heck, I even scrounged a fiberglass dash with 1200 decals intact. I might just install that 12hp, punch a hole in my QL side panel and run a stack out of the side. Skip: Does that mean I still have a Quietline? :HeadScratch :Extreme Fun |
|
|
|
| Pops | Mar 3 2009, 09:29 AM Post #9 |
|
I agree with all float or valves. By the way $200.00 for a new rebuilt motor I would be two stepping all the way to the guys door. Just a side note is the head tightened to specs. Pops |
|
|
|
| weaverama | Mar 3 2009, 09:47 AM Post #10 |
|
Yeah Pops, the head was tightened down to spec according to my trusty manual, the old gasket showed signs of leakage, something I neglected to share earlier. Did not check for warpage. Along with the 12hp Kohler there is a complete 128 for $25.00 sitting in a guys front yard. Barely salvageable but an interesting thought. hmmmm. |
|
|
|
| Jinks | Mar 3 2009, 09:49 AM Post #11 |
|
I am new at all this but I had a problem like this with my son's 100 that we pull with. It would seem to be running fine as we started pulling the sled but the further he got down the track the worst it got. An old gentleman told me that my generator was not charging and my battery was probably weak.Sure enough we checked generator and it was not charging.We charged battery and engine ran fine.We charge the battery before every pull now and it does fine.We run it straight off the battery at every pull.I know the 1000 dont have a generator but maybe this will help in some way |
|
|
|
| Matt G. | Mar 3 2009, 09:53 AM Post #12 |
|
If the valve seats look alright, you can just lap new valves with the old seats. That's what I did to my 86. The seats should be harder than the valves. I think you should be able to convert that 12 hp to a QL engine with the bearing plate, head, exhaust, flywheel, etc from your 10 hp. Then you won't need to cut any holes in anything. If you pull the head off again, you need to lap the head so it's perfectly flat and get a new head gasket. That probably isn't your main problem, but I doubt it's helping. |
|
|
|
| weaverama | Mar 3 2009, 10:17 AM Post #13 |
|
Matt, By "lapping" the head, does that mean the same as milling the head so that it is flat? And, are you saying the head on the K241AQS is the same as the K301 non AQS? |
|
|
|
| Matt G. | Mar 3 2009, 10:44 AM Post #14 |
|
I'm like 99% sure that a 10 hp head and a 12 hp head are the same. The head for the 16 has another bolt, and the 14 may have bigger areas for the valves. Kohler moved the spark plug around a few times over the years, so that's why you'll need the head from your K241. As far as 'lapping' the head...you could put it in a mill to true it up, but I don't have a mill. What's far easier (and cheaper, if you don't have a mill or the skills to operate one) is to get a sheet of glass and some wet-dry sandpaper. My dad got me a piece of 1/4" tempered glass that was a bit larger than a full sheet of sandpaper. I clamped it to a piece of particle board, and also came up with a way to clamp the edges of the paper down on the glass. I use 220 grit wet-dry sandpaper, but it'd be better to start with 180 (or 140, even) grit, and wet the sandpaper and place the gasket surface of the head on it and move it around in a figure 8 pattern. I'd use 180 or 140 until you can see that the entire gasket surface has been touched, (it's obvious) and then take some 220 and do it again with that to clean up the scratches from the coarser paper. Rinse off all the aluminum/sandpaper debris, and reinstall with a new gasket, torque to specs, and retorque after running 30 minutes at 3/4 throttle. I've done at least 10 this way, and I have yet to have one blow on me. Do you use the electric PTO clutch on your 1000? The only problems I can can think of that you may encounter are that the 12 hp doesn't have the tapped hole to mount the PTO clutch, and there may not be a provision for the right kind of dipstick on the older engine. Pictures of the 12 hp would help us determine if there will be any interface issues. |
|
|
|
| weaverama | Mar 3 2009, 10:57 AM Post #15 |
|
A piece of glass and wet/dry who'da ever thought!?!?. Yes, I have the electric PTO and that could be a stumbling block for me. Not too willing to start drilling and tapping new threads. Again the 3T's, time tools and talent. But that 12hp should slide right into the cradle of that beat up 128 that I can pick up for a cool $25. Other than the engine that is missing components it looks complete. Thanks to all you guys for helping me out. |
|
|
|
carb_3.jpg (71.26 KB)| Go to Next Page | |
| « Previous Topic · IH Cub Cadet Tractors · Next Topic » |
- Pages:
- 1
- 2
