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Intek 22HP won't run under load


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10-20-04, 10:28 AM   #1  
MicahO
Intek 22HP won't run under load

First post - looks like some very valuable help around here. My problem sounds very similar to this post from a few weeks ago.

Motor is a BS Intek 22hp, 407700 family, on a Husqvarna GTH2250, and yes, it's a whopping 6 months off warranty.

Motor was running fine, mowing along for 15 minutes about a week and a half ago. Shut it down, restarted about 30 seconds later as I had to answer a question from the wife. Upon restart it was coughing and barking at me, idle was very rough, and it didn't smooth out. I shut it down and let things cool for a while. 15 minutes later I had the same behavior. Same thing again an hour after that.

Since that point I changed plugs and fuel filter, checked fuel delivery, drained some of the tank, checked the air filter, blew a bunch of carb cleaner through, and dropped the solenoid on the bottom of the bowl to drain that out. Still had the same behavior - motor would backfire somewhat at idle, and when I put a load on it (either by movement or the mower deck) it would go all to hell.

I was actually able, once, to engage the deck at low RPM, bring it up to speed, and mow on a slight downhill. The moment I turned a bit uphill, the motor went to hell again.

I brought it to the Service Dealer I bought it from, they drained the tank, cleaned the carb, felt it was just water in the gas, and when they were loading it up to drop it off, they decided it was still running very badly. So they've placed a call to BS tech support.

I'm wondering if anyone has had any experience like this on an Intek. Based on the post noted above I'm going to ask them to do a compression check. Is there anything that might be a relatively simple fix?

Thanks much--

--Micah O'C

 
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10-20-04, 12:31 PM   #2  
Azis
Personally I haven't ran into anything like that as of yet, that wasn't fuel or carb related. Looks like your on the right track tho, hope you let us know how it turns out since the other thread has no definitive conclusion.

 
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10-21-04, 12:43 AM   #3  
Water in the system would be a good guess, but it sounds like they eliminated that. ??? Sounds fuel related, I agree. Could be ignition though...like a chaffed plug wire.


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10-21-04, 04:49 AM   #4  
MicahO
Posted By: cheese Water in the system would be a good guess, but it sounds like they eliminated that. ??? Sounds fuel related, I agree. Could be ignition though...like a chaffed plug wire.
I thought about the plug wire possibilities, or even that it was getting no or intermittent spark to one side or the other. What confounded me there was that the thing ran as crappy on one cylinder (one spark plug unplugged) as it did with everything connected, and that it ran that way with EITHER plug disconnected. When I unplugged the right side and there was no change in how crappy it ran, I thought AH HA! No spark on the right! Then for giggles I plugged in the right and unplugged the left. And it still ran like the same bucket of crap. So much for that hypothesis.

The shop is now working on the intermittent spark possibility. Based on the last post from that other thread, I'm going to ask them to do a compression test today. Could be degraded ignition on one or both sides? My confusion is how the thing could have been running so well and then just turned the corner by being turned off and back on. I've been as religious with maintenance as on my cars (spreadsheet anyone?) and it's only got 204 hours on it.

All of it, of course, makes me wonder why I didn't buy a Deere (which I was raised on), or stepped up to the Kawasaki motor. Lots of room for Monday morning quarterbacking......

If/when it sorts out I will be sure to post. Thanks for the feedback!

--Micah O'C

 
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10-23-04, 12:49 AM   #5  
I kind of doubt that compression is any issue here. Maybe a bad diode between the two coils. That would make the problem common to both cylinders.


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10-24-04, 05:32 AM   #6  
MicahO
Posted By: cheese I kind of doubt that compression is any issue here. Maybe a bad diode between the two coils. That would make the problem common to both cylinders.
The shop, in communication with BS support, hav also skipped the compression test. Apparently removing the right side plug wire did not reduce engine speed appreciably, while removing the left side wire dropped RPM's by a couple hundred (not what I witnessed, but I was not using a tacho). Based on this they are ordering a coil for the right side and will be replacing it when the part arrives.

more to come - thanks for the note about the diode between - no luck with the one coil, we may have to try there next.....

 
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10-30-04, 05:02 PM   #7  
MicahO
Quick update on this - the tractor is back at my house. The retailer/service place I brought it to had shot their wad. Their next step was going to be to call another shop and bring it there. I figured I would do that myself.

The engine is running better - though is not 100%. It is slow to rev, sounds all loaded up when increasing RPM, and when the deck is engages it bogs heavily, then catches up, but just doesn't 'sound' right.

They felt it was a water issue, dismantled and cleaned the carb, drained the tank, replaced all filters (claimed the air filter was actually wet, which I had not seen myself). Still ran boggy. Replaced plugs, finally replaced both magneto armatures.

The engine did run noticeably better upon replacement of the right side armature, but not all better. Replacing the left side made no further improvement.

I'm going to actually run it tomorrow and see how it handles a working load. Then probably call the other shop and bring it there for further inspection.

I'm also looking at sources for replacement motors - the problem doesn't seem too bad, but at this point I'm willing to spend some money, sell this motor, and let someone else have the problem. I use this tractor for blowing the driveway, and I've got to have it 100% before the snow falls......

 
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10-31-04, 12:46 AM   #8  
There shouldn't be any reason to sell the engine. There is a good reason for your problem, it just has to be found. There is still the possibility of a bad diode between the coils, which is a 50 cent part from radio shack. Also, check the wires near the starter. If one of them is pinched behind the starter, you could have these problems. No point in throwing out a good engine when you have experts here who are willing to help you fix the one you have.


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10-31-04, 02:14 AM   #9  
MicahO
Posted By: cheese There shouldn't be any reason to sell the engine. There is a good reason for your problem, it just has to be found. There is still the possibility of a bad diode between the coils, which is a 50 cent part from radio shack. Also, check the wires near the starter. If one of them is pinched behind the starter, you could have these problems. No point in throwing out a good engine when you have experts here who are willing to help you fix the one you have.
Was wondering about the diodes last night - saw another post that mentioned bad diodes in the ground wires from the armatures (different type of motor, don't know if this one has that). I've ordered the BS repair manual for these inteks and I'll see what it has to say about that. I'm not ready to sell the motor yet, though I'd consider a trade to make it someone else's problem

I do see the wire that runs between the two armatures, but it looks like a straight wire with nothing in-line. Is the diode on one armature or the other, and would that have been replaced when the two armatures were swapped out?

Thanks for keeping up on this--

 
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10-31-04, 09:37 AM   #10  
My approach to troubleshooting this problem would be as follows:
1) Start'er up an try to put a small load on the engine with one cyclinder's spark plug wire removed. Notice if there is a big difference between the power generated by each cylinder. If there is a big difference between cyclinders, is it possible to switch some of the ignition system components between the cylinders to see if the trouble will follow the component?

2) If both cyclinders seem to be about the same I'd hook up a timing light and see if there might be a problem in that area. Perhaps the ignition system produces a good spark, but at the wrong time.

It sounds like fuel system problems have been addressed as well as any compression issues. You are left with the ignition system and/or the exhaust system. From your description of the origional problem it's doubtfull that the exhaust system would be severly plugged, but you never know.

 
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11-01-04, 06:41 PM   #11  
MicahO
Posted By: jughead My approach to troubleshooting this problem would be as follows:
1) Start'er up an try to put a small load on the engine with one cyclinder's spark plug wire removed. Notice if there is a big difference between the power generated by each cylinder. If there is a big difference between cyclinders, is it possible to switch some of the ignition system components between the cylinders to see if the trouble will follow the component?
That sounds like a good test to follow - I'll give it a crack this weekend.

Further description. I ran the tractor for about two hours Sunday and mowed part of the lawn. notes -

->Even at idle, the exhaust note sounds 'heavy', like it's partly choked. I've tried moving the choke through various positions with no improvement. It does appear (from external inspection) that the choke plate is rotating fully open.
->When the throttle is all the way up, it doesn't sound like it's reaching full running RPM. The throttle cable IS mving the carb's armature over the entire range.
->the exhaust smells gassy when running
->when I'm mowing and going uphill, the motor is very surge-y (RRRRRRrrrrrRRRRRRRrrrrRRRRR) and sounds like it was under FAR more load than it actually is - it sounds like the tractor sometimes sounds when I run the snow blower and am eating into a snowbank at the edge of the driveway, yet there is really minimal load when it's doing this.
->Mowing and going downhilll it sounds loaded, but not surge-y.
->After enough surge-y running, it will pop and backfire a couple of times - heat related? Cutting the deck and letting it go at half-throttle for a few minutes, then returning to work stops the condition, at least temporarily, so I'm guessing that is heat related.

This thing drives a 44" blower in the winter and I will need it at 100%!

A new carb will cost ~$120 from BS. I've got a line on a
new replacement motor for $700, and a new 25HP for $850. I'm interested in the timing issue, but unsure of how the timing on this motor could be modified, as the armatures seem to read directly from a notch on the flywheel - no distributor to turn? Frankly, from playing with too many cars, it sounds like a 'simple' timing issue....

 
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11-01-04, 08:33 PM   #12  
From your reply it almost sounds like the engine is running way too rich. If it was you would tend to see some blueish smoke coming from the exhaust pipe while running. The rich condition could easily come from the float in the carb not shutting off the gas soon enough.

A car timing light can be easily applied to a single or two cylinder engine. I think that B & S may publish a spec for proper engine timing, but there isn't much to alter if you find that the timing is incorrect. I'm just thinking that it's possible for the electronic ignition to be screwed up enough for the timing to be wrong, perhaps only on one cyclinder. If you have a timing light a simple test only takes a short time and would give you some peace of mind to know that not only do you have good spark, but also it's occuring at the proper instant.

You could expect an engine to backfire if there's incomplete compustion of the fuel while it's inside the cylinder. The unburned fuel will be expelled during the exhaust cycle and be ignited when it hits the hot exhaust manifold. That's what you hear while the engine is popping & backfiring. Something like that usually happens when you quickly close the throttle after the engine has been running under a load. When the throttle closes you suddenly don't provide the necessary air for a cycle or two's gas load to combust and the excess fuel gets expelled before it can burn in the cyclinder. Improper timing can cause backfire as well as a mixture problem.


Last edited by jughead; 11-01-04 at 08:47 PM.
 
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11-01-04, 11:39 PM   #13  
I agree...by your last description it does sound like it's running too rich. Maybe the float level is too high for some reason? Loose jet in the carb? Of course ignition problems can also cause a gassy smelling exhaust and the backfireing if it is not allowing full ignition of the fuel in the cylinder. Pull both spark plugs out and report their color and condition.


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11-03-04, 05:26 AM   #14  
MicahO
Cheese - I think You 'da MAN!

I think I found the issue, and I it looks like the issue is spark, not gas or mechanical.

Last night I couldn't watch the election non-returns, and I couldn't get into the movie the wife and her friend were watching, so I went to look at the valves and see if something was stuck. I pulled the plugs first to make it easy to turn the motor.

I left the pictures big for effect -
http://www.bimmernut.com/~micah/imag...r/PB020003.JPG
http://www.bimmernut.com/~micah/imag...r/PB020004.JPG
http://www.bimmernut.com/~micah/images/Transfer/PB020005.JPG

These are what the spark plugs looked like after over two hours of running and mowing on Sunday. The plugs were brand new - I installed them Saturday morning at the shop before I took the tractor back home with me. The shiny, new looking plug is from the right side (when facing forward). That's the side that was first found to have a 'bad armature' by the shop.

There is a harness that runs to the two armatures, item 789a on page 7 of the parts list. The wires that lead to the armatures have diodes in-line. Apparently the right side diode itself or one of the connections was flaky, and is now probably just gone bad - this could account for what was inconsistent running and it's now consistently 'off' performance. I'd guess now that I'm running on one cylinder (the motor actually ran pretty damn well on Sunday with that in mind!). The popping when hot was unburnt gas from the right side popping off in the exhaust.

-->And I'm supposed to pay the shop for taking 3 weeks to NOT find this issue? I'll be on the phone with them today.<--

I've ordered the new part from BS ($27 shipped) and since I won't have it by the weekend I'm going to try and repair this harness with some diodes from Radio Shack this weekend. It obviously can't hurt to have a spare of this little wire around......

After all that, I did pop the valve covers and watch everything moving - all the valves were nicely gapped and moving as they should - thank goodness!

Cheese was the first to suggest those diodes, and it looks like that's the culprit. Could even just be a bad connection in that harness. We'll see this weekend..... Can't believe that in 3 weeks of 'testing' the shop never saw this......

 
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11-03-04, 08:52 AM   #15  
Azis
I guess I am confused by your conclusion
From the looks of the pics, I don't see anything conclusive showing spark related, infact I would think if spark was weak or intermitten on one side, that plug should have more deposits than the other. As it is the plug, (the one with deposits, looks like its on the left in one pic and on the right in another) is beginning to show signs of normal burning. Perhaps more run time would show more evidence.
If the diode is suspect, it can be tested with an ohm meter, it should have continuity in one direction and none in the other. If it is marked with either a band on one end(cathode -) or |<, Current should flow from the anode (+) to the banded end Cathode (-) but not the other direction.
If a connection is suspect, (cold solder joint?) test the connection cold, then put it in the oven let it heat up and check.
I know I havent had much input on this thread but I have been following it, but now and especially with this morinings news, I am even more against spending money on non-returnable parts without conclusive evidence.

 
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11-03-04, 09:57 AM   #16  
MicahO
Posted By: Azis I guess I am confused by your conclusion
From the looks of the pics, I don't see anything conclusive showing spark related, infact I would think if spark was weak or intermitten on one side, that plug should have more deposits than the other. As it is the plug, (the one with deposits, looks like its on the left in one pic and on the right in another) is beginning to show signs of normal burning. Perhaps more run time would show more evidence.
If the diode is suspect, it can be tested with an ohm meter, it should have continuity in one direction and none in the other. If it is marked with either a band on one end(cathode -) or |<, Current should flow from the anode (+) to the banded end Cathode (-) but not the other direction.
If a connection is suspect, (cold solder joint?) test the connection cold, then put it in the oven let it heat up and check.
I know I havent had much input on this thread but I have been following it, but now and especially with this morinings news, I am even more against spending money on non-returnable parts without conclusive evidence.
My conclusions may be wrong - but the plugs in the photos were in there for a bit over two hours of run. As you note, one plug shows normal deposits tht would be expected of a plug in pretty normal conditions. The other looks to be brand new and unused. My conclusion is that it is getting no spark - there would surely be some sign of use after two hours of run-time. If it was intermittent or weak, there would be deposits of some sort. If it was just sitting there, then nothing. (I did not have a chance to start the motor last night - I will be doing that tonight and will try it on one cylinder, then the other. I will also try swapping the armatures for effect.)

From there - the armatures are both new. The shop that was troubleshooting found the spark on the right side to be bad and replaced the armature on that side, with some improvement. Then they tried the left side armature, and found no further improvement. That's not to say that one or both of the new armatures wasn't bad, but the likelihood is relatively slim.

Which leaves the wiring to and from that armature. The plug wire looks good and was well connected, yet the conclusion above is that there was no spark on that side. Hence the focus on the diodes on the harness leading to the coils. I'm not terribly concerned about $27 and some of my time. After having the tractor at a shop for 3 weeks with little to no result, it is a drop in the bucket, and the part is one that was pointed out as a potential problem area very early on (cheese's second reply).

 
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11-03-04, 11:29 PM   #17  
From the looks of the plugs and the info given so far, I'd say you are not running rich, and the ignition is not correct. A blown diode is my bet here, once again. With a bad diode between coils, it can still spark, but will not spark at the correct times. Sometimes not at all. My bet is the diode on the LEFT kill wire to the left armature is bad. This allows the right armature to ground through the left coil windings, thus killing the spark on the right side.


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11-04-04, 06:36 AM   #18  
My $.02 for what it's worth, to my eye, it looks like the gap on your plugs is a tad big. It maybe that the photo just makes it look that way, but something to check. I've been reading this thread too, and haven't contributed either, because it stumped me as well. At this point, I strongly suspect Cheese is right.

 
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11-05-04, 07:03 PM   #19  
MicahO
Okay - in a chorus - Cheese - You 'da man.

Wife's away, kids are asleep. Bought a few diodes at Radio Shack today. Made one harness, and damned if it wasn't doing the same thing. Swapped plugs, swapped magnetos, swapped leads, and it followed the diodes. So I cut off the heat-shrink-wrap, and dumbass me had put one diode backwards.

So I did it again, with correctly oriented diodes, and it's all together, running smoothly, on two cylinders, like it should.

Tomorrow I get to tell the shop a thing or two, and bring in the Intek service manual they should have, that I sprung for, that describes exactly this condition (arrived today in the mail).

Thank you to everyone here. I generally spend far too much time on BMW forums, talking about old and new bimmers, and finding ways to fix them without having to give your money to the stealers. If there's ever any help I can provide - look me up! I've got most of the BMW service manuals and parts catalogs around on cd, along with a bunch of other marques.

Also - I've got this nice Intek manual if anyone needs anything copied....



--Micah O'C

 
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11-06-04, 10:49 PM   #20  
Great!!! Glad to be able to help. The problem you had is actually not a very common problem and as you have found...it can be tricky to pinpoint. The first time I ran into this problem it probably took me an hour to figure out what the heck was wrong. I went through the same procedures you did...swapping armatures from one side to the other, etc...

Thanks for letting us know how it went!


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