Here's something a little different -- a self-propelled reel-type mower, probably from the days when cars didn't have seat belts.
Model No. is 150-518-004. Serial No. is 74377. Looking up that model number on MTD's website got me nothing, unsurprisingly.
Note that there's no spark plug wire -- not an encouraging sign. So that's the first order of business here -- to get the cowl off the engine and see what's what with the missing spark plug wire.
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And here we are with the cowl off the engine.
Hmmm. The ignition coil is missing entirely, and what I take to be an air-vane governor is in utter disarray.
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Replacement Ignition Coil -- WEDNESDAY, NOVEMBER 14, 2018
A replacement coil is supposedly Briggs & Stratton part number 591420. That part represents a conversion to solid state ignition; it would render the points and condenser irrelevant.
An OEM coil from the small engines shop is $72.92 CDN -- that's a heap of money. Amazon lists it for $48.03 CDN. My son is going to see what's available on Ebay.
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Ignition Coil Obtained -- WEDNESDAY, DECEMBER 26, 2018
See this post for the story of the coil's installation. That linked post also has a good photograph of the correctly assembled governor linkage.
The Ignition coil installation was successful, and the mower now has a working engine.
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Engine
Engine model/type/code number is 60102 0294 01 690801. According to "Chilton's Guide To Small Engine Repair Up To 6 HP", the first five digits of that number signify the following:
6 = 6 cubic inches displacement.
0 = basic design series [whatever that means].
1 = horizontal Vacu-Jet carburetor.
0 = plain bearing.
2 = rewind starter.
The engine no doubt predates solid-state ignition, so there will be breaker points and a condenser under the flywheel.
The next step is to pull the flywheel and examine the points and condenser.
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And here's a view of the points-and-condenser arrangement.
That appears to be in good order. Breaker points gap for this engine is 0.020".
Spark Plug
The engine's Operating Instructions call for a Champion J-8 plug. That's a 14mm, gasketed plug with a 13/16" hex. Gap is supposed to be 0.025".
The spark plug that's in the engine is an AC LM46, in reasonably good condition. It's a non-resistive type.
Air Cleaner
The air cleaner appears to be on the wrong way around.
It's covering the fuel tank's cap. Here it is correctly oriented.
Inside the air cleaner's enclosure is a foam element that's maybe still serviceable.
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Fuel Tank Cap Gasket
The original gasket is badly embrittled. I made a replacement from some 1/16" thick cork gasket material.
The venting arrangement on old Briggs & Stratton fuel tank caps will admit rain. Don't leave an engine with such a cap out in the rain uncovered; you'll end up with water in the fuel tank. I believe that Briggs & Stratton has finally solved this with a fuel tank cap design that vents from underneath its perimeter.
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V-Belt
The V-belt measures 19 3/4" outside length. There is no OEM part number visible on it. A 20" belt might work.
The belt looks serviceable, although it has one break in its traction side. From what I've seen of worn V-belts, their strength is all in their outer spines; their inner 'V' portion is just tractive 'filler'. They can have breaks in that area and still function, so I won't pursue getting a new belt for now.
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V-Belt Pulley Alignment -- SUNDAY, NOVEMBER 18, 2018
It's not good.
The engine's pulley is too far inboard. There's shaft-length enough for the pulley to be moved over into alignment with the driven pulley on the countershaft. I'll see if I can persuade that rusty arrangement to loosen up and let me adjust the engine pulley's position.
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Much Better
I loosened off the pulley's setscrew with a 5/32" hex key, put a three-jaw puller on the pulley and was able to shift the engine's pulley into alignment with the driven pulley. The engine's pulley didn't want to come all the way off, though -- the shaft is not badly rusted, but it's rusted enough that the pulley won't come off readily.
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V-Belt Tension Idler
The tension idler is just a shielded-both-sides ball bearing that bears against the inner surface of the belt to tension it and engage the drive. The bearing feels a bit grease-starved and rough.
Removing a 5/16"-18 x 5/8" hex head screw allows the bearing to come off its bracket. Here's a view of it along with its retaining screw.
The bearing is a NICE 3023-DS; 5/8" bore x 1 3/8" O.D. x 7/16" width. There's no way to repack it with grease. I'll clean it up and get some oil seeped into it as best I can.
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A V-Belt Tension Idler Anomaly -- TUESDAY, NOVEMBER 20, 2018
I was wondering why the operator's DRIVE ON/OFF lever only had about half of its possible travel, and why drive disengagement wasn't terribly effective. It turns out that the tension idler's positioning crank had gotten flipped around 180 degrees from its normal position. It doesn't photograph well, but here's a view of the correctly positioned idler arrangement in its OFF position.
Note that the idler bearing is well away from the belt. Belt tension is truly relieved, and the drive is disengaged.
And in its ON position.
The tension idler bearing is permitted its full, spring-loaded travel down onto the inner surface of the belt. The belt is tensioned and drive is engaged. The operator's DRIVE ON/OFF lever now has its full travel.
Note also the washers underneath that upright piece that's supporting the tension idler's positioning crank. Those are not from the factory, and have no reason to be there. I'll be deleting them.
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Combustion Chamber Cleaning
The engine's Operating Instructions recommend a combustion chamber clean-out every 100 to 300 hours of operation. It's likely never been done on this engine, and I've never done one on a small engine, so I may as well go ahead and do it; it will be interesting to see the state of the combustion chamber. And while I'm at it, I may repaint the scruffy looking upper air baffle that sits on top of the cylinder head.
And here we are with the head off the cylinder.
That doesn't look too bad at all. There may not be all that many hours on this engine. The cylinder wall looks good.
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Combustion Chamber Cleaned -- WEDNESDAY, NOVEMBER 21, 2018
Here's a view of the cleaned up cylinder head alongside its new gasket. It's not immaculate, but it will do.
The gasket is Briggs & Stratton P/N 272167. The original gasket tore a bit when I lifted off the cylinder head; it wasn't fit for reuse. Some observations on the matter of combustion chamber cleaning:
- Work with the piston at top dead centre, with both valves closed. Have compressed air available for blowing away debris.
- Have a new gasket on hand. The original is unlikely to be reusable.
- My original gasket was stuck to the top of the cylinder in places, and 'welded' to the cylinder head. It took some serious scraping to get all the remnants of it removed.
- The carbon build-up is stubborn stuff; it has to be scraped off. I know of no solvent that will dissolve it. Oven cleaner might work, but that would involve a mess that I'm not prepared to make.
- There are YouTube videos out there about this subject. From what I've seen of them, they're utter nonsense. I have no idea why people take the trouble to make them.
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Muffler -- FRIDAY, NOVEMBER 30, 2018
The original muffler looks pretty rough, so I got a new replacement.
That new muffler down in front is what's known as a 'sausage' muffler. Briggs & Stratton P/N is 89966. The thread on it is 1/2" NPT (National Pipe Thread).
I can see now that the severe offset of the original muffler's body had a reason behind it -- it's to clear the very nearby carburetor. The new sausage muffler just barely affords clearance for the carburetor.
The muffler also just barely clears the underside of the air cleaner that perches on top of the carburetor. Anyway, 'just barely' will do.
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On Second Thought -- WEDNESDAY, DECEMBER 26, 2018
I decided to put the original muffler back on. The original muffler has a deflector on it to blow exhaust sideways -- away from the mower's operator.
The sausage muffler would blow exhaust gases straight back toward an operator. There are reasons things are the way they are on machinery. One makes alterations at one's peril.
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Final Drive Roller Chain -- SATURDAY, NOVEMBER 24, 2018
Removing a small cover from up on the mower's deck gives service access to the roller chain final drive.
It's a half-inch pitch chain, but it's narrow; it's not the common No. 40 or No. 41 half-inch pitch chain that I can get from Princess Auto.
Roller diameter and overall chain width are each just shy of 5/16". Roller length is about 1/8". There are 48 links, for an overall pitch length of 24". There's a maker's logo, "D.I.D", stamped on the chain's links, and that firm appears to still be with us. But these days they don't seem to be making that small size of chain -- they're strictly a supplier of motorcycle and ATV chain.
The chain is a little worn and saggy, and it's rubbing on the edge of the hole in the deck that it feeds through. I may end up just giving the chain a good lubrication and leaving it be.
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Roller Chain Update -- FRIDAY, NOVEMBER 30, 2018
I found out what manner of chain it is -- it's 1/8" bicycle chain, like this.
It's narrow, 1/2" pitch chain. The 1/8" figure is the chain's roller length. Bicycles with single rear sprockets, such as coaster brake bikes and bikes with Sturmey-Archer rear hubs take 1/8" chain. There's a narrower, 3/32" chain that's used on bikes with derailleurs.
So, it turns out that I have replacement chain on hand, should I decide to give the mower a new chain.
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Drive Train -- TUESDAY, NOVEMBER 27, 2018
Following is a list of all the drive train's engagement components, for any who'd care to do the math:
- Engine Pulley: 2 3/8" O.D.
- Countershaft Pulley: 4" O.D.
- Countershaft Sprocket: 9 tooth.
- Reel Sprocket: 27 tooth.
- Wheel Drive Pinion (rotates at reel speed): 11 tooth.
- Wheel Ring Gear: 77 tooth.
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Wheels About To Go Back On -- FRIDAY, NOVEMBER 30, 2018
Here's a view of the inside of the left side wheel, with its back-plate and drive pinion in place.
I'll grease the gearing and the wheel's axle bearing with white lithium grease prior to assembly.
The mower's original left side axle bolt and nut were lost and replaced at one time with common hardware components -- a 1/2" carriage bolt and a square nut, 7/8 A/F. That arrangement works remarkably well, but it's not quite right. The replacement parts are right-hand threaded, so wheel rotation is in the direction of loosening them. I'm certain that the original parts were left-hand threaded, so that wheel rotation would be in the direction of tightening them. In reality, the loosening forces generated by wheel rotation are negligible, and I don't expect there to be any problem with the left side wheel. But it is another example of the harm that inept tinkers do to perfectly good machinery.
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Recoil Starter Cog-And-Ball Clutch -- SATURDAY, DECEMBER 1, 2018
The starter clutch is also the flywheel nut.
Much the same style of clutch is used on Briggs & Stratton's vertical shaft engines. See this post for more on that. On horizontal shaft engines, DO NOT remove the clutch's cover with the clutch in place -- you'll have six steel balls spilling out.
To remove the clutch, restrain the flywheel and apply a pair of 12" Channellocks. Take care not to distort the two screen-mounting ears. There'll be a slightly convex washer under the clutch; note its orientation.
Here's a view of the clutch dismantled.
Note the felt disk at the centre of the photo. That's a lubricant wick from up inside the clutch's spindle. After cleaning and drying it, give the wick a soaking with WD-40 before poking it back into place with the shank end of a 1/2" twist drill.
All parts of the clutch should be immaculately clean. Use no grease or oil whatsoever on the balls and ball cavities. Here's a view of the clutch partially reassembled, awaiting its cover.
At reinstallation, lubricate the cover's seal and the bore of the spindle with WD-40.
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Engine Oil Change
Sump capacity is 1 1/4 US pints, which is 20 US fluid ounces or about 590 ml.
The square-headed 1/4" NPT drain plug is 3/8" A/F. Fill level is full to overflowing from the fill/inspection hole.
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Recoil Starter -- SUNDAY, DECEMBER 30, 2018
I wanted to paint the engine's cowl, which would best be done with the recoil starter removed from it. Also, the starter was in need of attention anyway -- grime and crud buildup inside were making its rewind sluggish.
Recoil starters are not a pleasant item to deal with. Keeping the spring under control while it's rewound and the cord is installed can be challenging. Following are some photos and notes on my go-around with the starter.
A Crank Rod
You need a safe way to restrain the pulley as you unwind the spring after detaching the cord. On this starter a 23/32" square length of wood served as a crank rod, like so.
You want to count the number of turns it takes for the spring to completely unwind, so you can reproduce the necessary spring tension at reassembly.
Note the two tabs that are folded over the perimeter of the pulley. Those tabs must be bent up straight in order for the pulley and spring to be removed. There are two spare tabs available for use in the event that the tabs break off on you from fatigue.
Here's a view of the unwound spring with the pulley removed.
That's a view of the spring after cleaning. I didn't use grease on the spring for fear of it turning to sludge in time. After final assembly, I sprayed in a fair bit of WD-40 for a lubricant.
Retensioning The Spring
Here's the starter back together after almost six turns of the pulley to retension the spring.
The Vise-Grips served as a crank handle. The c-clamp is there to keep the thing from unwinding while the cord is reinstalled.
Threading in a cord is a bit of a chore, but it does go into place. A simple knot at the pulley end of the cord is all that's needed to secure the cord there, though I added some CA adhesive just to be certain.
Finishing Up
At the handle end of the cord, you can use a spring clamp for a restraint while you work out the cord's length.
Cowl Back On
Here's a view of the engine with its cowl, fuel tank and air cleaner repainted.
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Update -- TUESDAY, MAY 28, 2019
The mower has overwintered in the garden shed with its fuel tank emptied. I fueled it, and it started up easily and runs fine. I tried it out on some grass and it cuts reasonably well. A problem arose, though; the left side wheel came loose. I wasn't surprised at that. Old equipment that's been tinkered with is almost guaranteed to have problems built into it by tinkers, and this mower is no exception.
The left side wheel's axle is supposed to have a left hand thread on it, unlike the right side wheel's axle which is right hand threaded. The different threads are designed to resist loosening from the turning of the wheels. Right side wheel forward rotation will tend to tighten a right hand thread; left side wheel forward rotation will tend to tighten a left hand thread -- loosen a right hand thread.
The original axle screw for the left side wheel on this machine was lost at some point, and replaced by a right hand threaded axle screw. The forward turning wheel exerted a small but relentless turning force on the axle that succeeded in loosening it from its nut.
I've added a jam nut to the assembly, like so.
That should take care of the problem.
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