Wilbur, well at least you know it had to come apart. From here I think you will have to wait for AVB to come along as he is the go to man on this Briggs stuff
From you have done does indicate a failed governor. And no it doesn't take special tools to do the work though you might need clean the crankshaft PTO end so slips pass the seal and bearing surface of the cover. A few I ran into with rust.
With feeling a bump while holding arm makes me think the governor gear is stripped or you have a sheared key on the crank gear but you will not know for sure without going in and looking.
I posted this before realising the thread had gone onto page 2, so I thought I better repost here. Hope this is ok
Ok, motor out, pulley off (slid of with only hand strength needed). Cases split. Photo 1 shows what I found. When lifting the motor out, I'm pretty sure I heard the components cluncking around in the bottom case, so I think it had come apart and caused my problem. I suppose I have to hope so.
Photo 2 is a closer look at the loose components. I can't see any evidence of a problem (other than the weirdly shaped hole in washer), although I don't know what holds the pieces together if the bottom case doesn't hold them up.
Photo 3 shows the end of the shaft of what I assume is the governor unit. Not sure what it should look like really. It is flattened, but not crisply.
So, how do I proceed from here?
Is where I found them irrefutable evidence of failure?
Norm, I managed to do it before your advice came through, so I didn't have the benefit of your suggestion of tipping mower. It wasn't too bad doing it in upright position, but more time consuming I guess. A worthwhile tip for the next time (hopefully not too soon).
Well that looks like it kill it and I hate to be the bearer of bad news.
The shaft sticking out of the governor is should to be pressed in place right below number one cylinder as shown the image below. The problem is that this early model engine crankcase is NLA; therefore , you would need a new engine. Red circle stud, Orange square bad spacer washer
Ah well, such is internal combustion engines. It's such a pity when something seemingly minor sends an engine to the recycling area at the tip.
So as a summary for anyone in the future experiencing governance (is this the correct use of the term) problems, here's my take on it (although I could be wrong and would be happy for anyone to correct me). Similarly, I don't know the right names for each of the parts we are talking about here. For instance, now I see the set up, using the term governor shaft is ambiguous at best. I have made up my own terms in an attempt to clearly distinguish between parts, but if there are correct terms or better terms, please correct the record.
SUMMARY:
1) excessive range of rotation of the governor shaft probably is a diagnostic tool
I really think that, despite what I said earlier, that the 90 degree rotation of the shaft initially was real and symptomatic of the type of failure I experienced- UNLESS my understanding of how the unit is set up is wrong. The governor gear shaft somehow came free from its pressed connection into the upper case, fell to the bottom of motor, allowing the governor arm shaft a wider range of rotation. The reduced motion I experienced later was because the displaced pieces got in the way of the lever on the end of the governor arm shaft.
2) no evidence other than the racing motor was apparent- no metal in oil, no obvious performance problem upon start up.
3) the fact that this problem arose immediately after carburetor repair was pure coincidence, as was the starter motor problem
4) 630 hrs of operation before failure
630 on the clock- no guarantee this is the original motor). I can't speak for the maintenance schedule of the previous owner, but in the short time I have owned it (probably on 50 hrs of operation), I have routinely changed oil and filter, with little else done to motor. I hadn't adjusted valve clearances or anything similar. I have been too busy fixing the drive, perhaps unnecessarily.
QUESTIONS (AVB?)
1) so if it were possible to somehow attach the governor gear shaft in the upper case it may fix the problem (if only temporarily)?
2) does knurling the shaft actually raise metal on the high spots? This would effectively increase the shaft diameter, and thus potentially allowing a refit?
3) what about having a new shaft made up, slightly oversized where fits into case? Would need to drill out the hole to accommodate.....
4) is there any other way of permanently joining the shaft to the case, even if it only brings limited extension to the life of motor?
5) what actually happened here?
The shaft somehow became loose by the hole in case becoming elongated or something similar? The shaft itself shouldn't wear because it's just a press fit?
Next, the arm on the end of the governor shaft that can push up on the governor gear shaft when fully rotated counter clockwise doesn't hold the gear assembly in place and there was room for it to fall into the bottom case?
6) Is this a common internal failure?
We have spoken of the decompression valve failure that can lead to governor failure, but mine has no such set up. Is this an Intek specific problem? Twin cylinder v single?
7) Is there anything that would hold off a failure like this?
8) If I install a single cylinder Chonda, I imagine there will need to be significant throttle and choke cable re-engineering, fuel line modification and electrical work done. Anyone got any experience with this? Easy? Difficult?
AVB, do you think it might be able to be held in place with one of the Loctites. I remember fitting loose cam spindles in an Enfield, think I used 620 but the other end of the spindle was supported in the timing cover so flexing was not an issue. What is the damaged washer, is it just a thrust washer up against the case. Any thoughts as to why the hole would get damaged like that, seems a bit odd.
A lot good questions which I don't answers for. But a few I can answer though.
Yes knurling does raise the shaft metal effectively increasing its diameter. Here I use it on spindle shafts where the ID of ball bearing is slipping on the shaft journal. This slippage actually wears out the spindle shaft bearing journals. Also years ago it was a way to repair bad valve guides in automobile engine when they had none replaceable guides.
An oversize shaft would work but how do you get the right size circlip to hold the governor on the shaft or how to position it retaining groove on the shaft? A machinist could copy the profile to the new shaft.
Why it came out may be caused excessive heat expanding the aluminum crankcase. Just don't know here as it is the first one I have seen or heard about in my 10 yrs of working on these Briggs engines.
The problem with thought on the governor cross shaft holding things in place is that the push pin moves in and out allowing a loose shaft slide out of place so I don't think it hold position if just place back in loose.
The ACR problem I have seen all have been on the Briggs 28, 31, and 330000 series using the 793880 camshaft. Of course ACR do fail on other brands too just as obvious as the Briggs.
I think you was just the unlucky user to have this happen to. I haven't seen service bulletins indicating this a common failure either.
Now Norm personally I don't trust Loctite or an epoxy is this setup but someone with more experience might know of something or method that would work. The washer serves both as a thrust washer and way for oil to get upper part the governor assembly. As for hole damage I have no idea unless got damage as the governor failed.
I'm just the kind of guy to not let go of this problem until proven irreparable. Hence I'm prepared to entertain the idea of a repair, particularly as I can access lathes and operators at a reasonable cost and sympathetic to repairing rather than throwing out. Having said that, we are nearing the end of this Briggs adventure.
I haven't fully checked out the governor gear unit but understand that there are two parts to the shaft, allowing sliding to occur, effecting a change in position of the pivoting counterweights.
I have refitted the governor gear unit in top case to assess hole enlarging. It is certainly loose, sliding in and out freely, in fact with no resistance. Having said that, with the shaft fully inserted the play at the end of the shaft (bottom of shaft protruding below gear) is less than 2mm I would have thought. That would equate to less than 1mm (approx) of play at the opening of the hole.
Would knurling have a chance of picking up 0.5mm all around the shaft?
Would the gear apparatus need to be taken apart (I suppose counterweight pins would need to be ground off) for any machining to be done?
If and when the enlarged hole is made uniform by drilling out, I'm wondering what sort of tolerances need to be thought about when considering gear engagement. I would hope that it might be possible to drill out carefully, with the new hole being centred well enough for those tolerances to be at least not an immediate problem. Tight gears would obviously be a problem. Is suppose this strikes at the heart of whether or not that part of any attempted repair can happen without further stripping of the motor. That would be it for me.
As always, thank you for your advice and opinions. I have learnt a lot, and at least tried to avoid being part of the throw away society in which I live. Sharing knowledge and experience online is a great thing. I hope this thread can be of value to others.
Wilbur, this is not just an easy fix up, no drill to go near it. I'm not 100% sure what you are planning but if you plan on opening the hole and getting an oversize pin made, this is all work to be done by a very experienced machinist. The case would need milling out and an O/S pin made to suit. Finding somebody who can do this work is not easy. Then the cost quickly starts to add up and at the end of all this you still have an old engine
that's all I needed to hear to convince me of the difficult path ahead should I attempt a repair. I'm running the white flag up the pole as we speak. It has defeated me.
I think that the hole has opened up enough that unless knurling and loctiting could secure the gear unit, something along the lines you describe would be necessary. And that isn't feasible.
Unless AVB thinks there is a chance of knurling working given the hole enlargement described, we can well and truly say RIP engine.
I'm considering another Greenfields as an immediate and cheap replacement, and if it fails I will fit one with a Chonda. Plenty of spares if I buy the one I'm thinking of because same unit- frame, body, deck, drive, just with a 17hp motor. And I've now developed a level of knowledge of the drive and other features, it seems a pity to go to something with a drive system I don't know anything about. It will hurt to part with over $5000 on a new mower that could do the job- a club cadet tractor (XT2 LX42) or zero turn (the RZT S series) are the recommended units. Happy to hear anyone's opinion on these mowers.
I suppose that about wraps up the governor issue anyway.
Wilbur, all I will say is stick with the Greenies, they are far more robust and repairable than the other stuff. While you have this motor off could you take some measurements on the bolt hole so we can see if it is a standard Briggs bolt pattern
I've included a photo of the rough dimensions of the mounting bolt pattern. If I've misunderstood, let me know and I'll get the measurements you were after.
I think you are right to stick with the Greenies. It suits me better, even if I do need to do a bit of work. They all need some work, even from new. My brother in law's new Cub cadet RZT S series is already throwing belts before its first service (albeit overdue- could be entirely their fault).
I should pick up my new old Greenfield in the next week, and hope for at least a few hours of trouble-free cutting.
The scientist in me wants to find the best glue on the market for metals and put the old engine back together (for fun only) to see how many seconds it runs for before throwing the governor away again. Reality will prevail though. It will sit in the shed for far too long before being offered as parts. I suppose this forum would be a good place to make that offering, when the time is right.
Wilbur Greenies are not the most sophisticated but they won't send you broke either with big repair bills and replacement parts all the time. Very rugged machine that you are able to repair fairly easily. You can contact the Loctite distributors (I forget who they are) and tell them what you need to achieve and they can put you onto what they think is best. Some of the Loctites are very strong, I have been told that one of the drive gears in a BMW gearbox is only fitted using Loctite on a straight shaft so it must be pretty good. I will check the bolt pattern tomorrow because it is a question I asked some time ago and did not get an answer. Good chance it is the same as the small Briggs motors from those measurements
in looking at replacement motors, I noticed that the Jono and Johno replacement motors (Chondas or similar) show the mounting bolt measurements. Their 17.5 single has the same pattern as my motor, but their 20hp twin is different. They claim both of these motors have the Briggs and Stratton pattern. From your comment it seems that there are at least 2 Briggs patterns, for different sized motors?
Those measurements don't match the smaller Briggs motors but they do match an 8HP I have so I'm not sure at what HP they change. I know I did get caught fitting a 6HP Chonda on a small Greenie a few years ago. It was claimed to be Briggs pattern, had a 25mm shaft but it turned into a terrible job drilling the new holes to get the motor in the right position so the belt tension was right. I'm just wondering, as I didn't think about it before, but maybe that motor was a push mower Briggs pattern. I also have a 16hp twin here but as it is still in the mower it is a bit too difficult to measure. This might push that project a bit further up the list now. A few weeks ago I also came across 2 push mower motors with 25mm shafts and this just clouds the water a bit more, the only reason I noticed was when I went to change the boss on them . One was on a Greenie push mower with a Briggs Quantam motor that had from factory the blade carrier welded to the boss. I had to end up cutting the blade carrier off and destroy the boss to get it off. No way you would need a 20HP motor on your Greenie and one thing you must think about is these motors do not have a fuel tank, I'm not sure what the fuel tank situation is on yours, seeing it had a bigger Briggs there would not be a lot of space under the bonnet. I had to make up a fuel tank for a mate to fit up inside the front of the bonnet when I fitted a 13HP Chonda in his.
Norm, I had thought about the potential for the fuel tank to be an issue, and adapting throttle and choke cables, electricals etc. Made the idea of the new old 17hp Greenie that little bit more enticing. Hopefully it will be nice to me.
I'll post a few photos of my old Greenie for the record in my next post, just in case it helps anyone unravel a mystery. Do we have a better place to put those sort of photos or should I just post them here?
Incredible that Loctite might be good enough for BMW. I suppose I would be asking for a glue that also filled a bit, given the fact that the shaft is no longer even snug. Nevertheless it would be interesting to see what would happen. My guess is it would work for about a minute. I like the idea of the experiment, though. The problem is, if it worked, wouldn't I feel foolish if I hadn't replaced the thrust washer and the case gasket and and and......
I'd be interested to know what sort of hours can be got out of ride-on sized Briggs motors. Mine had 650 odd hours on it, and as far as I know it was without problem or significant signs of wear. It didn't use oil, ran powerfully and smoothly right up till just before the governor killed it (Well, there was about an hour of rough running because of the carbie o-ring having gone and the motor running extremely rich, and a bit hot). If that was a car motor, I reckon that would be equivalent to about 40,000kms (?). I know someone who bought a new Holden ute and didn't get it serviced (no oil changes at all) for about 60,000kms. He then drove it up to about 150,000 and it was absolutely fine.
Anyone heard of a 20hp Intek motor with thousands of hours on the clock?
As AVB alluded to earlier, maybe overheating caused the governor failure, so I should reiterate that there was a short period (say three half hour sessions) of time that the motor ran very rich due to carbie problem immediately before I fixed it and started up the motor. Failure was at the very instant of starting, unless it happened as I turned it off before carbie repair. Seems a bit too coincidental, I would have thought. Then again, the starter motor decided to fall apart at pretty much the same time. I had thought that they all might have been linked had mine had a decompression device for start up. As said before and confirmed by AVB, similar motors were fitted with these devices, they were known to break, sometimes taking out the governor. That would have made start up more stressful for the starter, potentially precipitating its failure shortly after. But that wasn't the case. AVB has never seen failure like this. Awesome. I'm an exceptional failure.
Sorry for not being around. Out sick due over spiced meal I cooked. On day 3 and things still tossing and turning but finally improving. I got to go light on that Cumin.
As being over rich usually the extra fuel cools the engine it is going too lean that over heat them.
I have ask my co techs on the forum I manage here and one in Kentucky said he has only seen three engine to fail like Wilbur's. His shop is a lot larger than mine.
Personally I haven't seen any Briggs with thousand of hours on them but what I usually deal with the cheaper non cast iron cylinders anyway. I do have few clients that are approaching the 600 hrs mark. Most the engines I see with a 1000+ hours on them are Kawasaki and Kohler and they are larger ZTRs used for commercial work.
May this will help on the bolt pattern. It is a little heavy on measurements you should still be able figure it out. Meanwhile I got to go back to the restroom to throw up my socks.
Hope you are recovering well, AVB. I love my spices, but have friends that have to be careful so as not to disrupt the natural order in their guts.....
If many motors of this size (ride-on) give up after 600 odd hours, and my failure is rare, what commonly kills them?
Is there anything about mower engines that kills 'em quick? It seems to me that 600 hours is, as I said previously, equivalent to not many kilometres by a car (@60kph= 36,000km). I would have thought that 20hp on a ride-on the size of a Greenfield would hardly be labouring doing what it does....... Does being air cooled make a significant difference? I don't think any motorcycles would expect the same lifespan as a car engine, but they are generally higher performance units.
I would do at least 2 hrs mowing a week, and this would mean that from new I could only expect 5 or 6 years before replacing. To be honest, I would be disappointed with that, particularly had I maintained it as per schedule.
Genuine Hondas are not in a different league altogether?
Norm, I'm glad to see my measurements were at worst only 0.58mm out. It wasn't easy to get a perfect measurement using tape measure and estimated centres, although I did end up measuring side to side, rather than centre to centre. Interesting to see the spacings are not whole numbers (mm) or even common fractions of inches (7.07 inches?).
I better go and push that long suffering Victa pro460 2 stroke around a bit. $30 at the markets years ago. I reckon it has done 600hrs for me and is still going strong (I hope I haven't jinxed it).
Having heard that most ride on motors only run for less than a thousand hours means that the second hand Greenie I'm looking at will want a Chonda very soon as it has over a thousand on the clock. It mightn't be the original though, and as it had a new deck put on it a couple of years back, and drives well, I won't be that disappointed.
Thanks AVB, hope you are feeling a bit better shortly, the old food poisoning is never nice.Those measurements tally up with Wilburs. Wilbur those big motors have a fuel pump so you can fit a tank anywhere. I have never heard of a 13 being under powered, they built plenty with 8HP motors, I assume yours only has a 32 inch cut so the extra power is not needed
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