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Discussion Starter · #1 · (Edited)
Guess I got a little carried away last week, revving the engine to try to figure out a fuel delivery issue. Turns out, that was a split in the vacuum tube for the fuel pump, but I didn't figure that out until I grenaded the governor gear. Gotta love Amazon.

Ordered a few parts as well as some new blades for my little orange Husqvarna. Parts came in late yesterday. I'd already done everything I could short of assembling the govvy gear, because I already had new filters, gaskets, main seal, and a boring afternoon on Sunday. The original govvy gear was in about 8 pieces when I opened up the case, so there wasn't any hope of recovering it. I'm just glad I have the later vintage engine with the spoked cam gear rather than the solid one, because the pieces went through it rather than between the teeth of the cam gear and the crank gear. After a bit of study, I figure that govvy gear is turning nearly twice as fast as the crank, 4x the cam. That's boogyin'. Silly me poked the govy a little hard, then had a run-away. Fortunately, I could reach the switch quickly and shut it off. Knew EXACTLY what I'd done when I did it. This is one of the reasons I hate an internal governor.

Decided to go for it today and finish the reassembly. Pulled the lifter rods to loosen the cam, dropped the gear on top of the thrust washer, put the circular keeper on, verified the gear wouldn't come back off, finagled the top-hat on, and Bob's yer uncle. Sump dropped on to within 1/8" closing as soon as I got the main shaft seal to clear the shaft. 0001 misalignment of the dowels could easily stop it, so I had no issue with a little bit of light shock therapy holding the hammer head in my hand and tapping the sump with the handle of the. Couple wiggles, a light tap with the handle of my 1/2 pound ball peen around the perimeter of the sump, and it was sealed up without bolts. I used Permatex HyTak on the gasket. I owned and worked on a VW for nearly 35 years, and ya can't beat that stuff for standing up to oil, fuel, and heat. I got used to air-cooled engines, and learned to like them not having antifreeze as something else you had to clean up off the floor.

HyTak does NOT like acetone, though, which makes for a dandy cleanup if you ever have to remove it again. Just grab the wifey's nail polish remover, and in a few minutes, you've got a clean gasket surface.

Got new bolts with the sump gasket when I ordered it last year because I thought my sump was leaking. Turns out that was a leaking oil filter, and I was a happy camper that I didn't have to pull that engine apart. Blowing up the govvy gear didn't leave me much choice in the matter, though. New bolts already had nylon thread lock, so torqued them to 320 lb-in or roughly 27 lb-ft in 9 lb-ft increments, criss-crossing and going around the perimeter the way I was taught by a VW mechanic about 50 years ago. Per the service manual, on the Inteks, 200 lb-in is if you re-use the original bolts and your own thread lock, but 320 if you replace them with OEM bolts with built-in thread lock. Most after-market thread lock is little more than high density sugar, and tends to make bolts corrode where steel threads into aluminum. I learned this the hard way on VW engines. It ain't nice when a head stud pulls out of the block and you hear that tell-tale POP POP POP when the head starts leaking, or when you're trying to get the headers off and the stud just twists off rather than backing out. Drilling steel out of an aluminum block or head is ALWAYS a load of fun.

Reassembled the oil pump, put the lifter rods back under the adjusters, and rotated the assembly a few times to make sure I didn't hear or feel anything bad and that both valves were working on both cylinders. (Did I mention I took the plugs out during disassembly and repair to make this part easy?) Turned the throttle disc to WOT, turned the govvy shaft to full CW rotation, tightened the bolt. Rolled both cylinders to TDC to check/adjust the valve rockers to .004 lash as specified. Seems tight to me, but I'm used to VW's with .006 clearance and Fords with NO clearance because of hydraulic lifters. After reading about and seeing the dissimilar lifter rods, I have to scratch my head and wonder how many of these are assembled wrong with the steel and aluminum lifter rods in backward. I've owned my Husqvarna since it was new, and was quite shocked to find #2 cylinder lifter rods swapped. This engine has NEVER been apart before, so it was assembled wrong at the factory. Guess I got lucky that I didn't have any valve train problems. Put 'em all back in right after the discovery (aluminum lifter rod on the intake, steel one on the exhaust), and verified the lash at .004 on all four valves, and that the lifter rods would easily spin on a closed valve. Put the new vacuum tube on #2 cylinder Valve Cover, put a nice thick bead of RTV on the VC's and re-installed them.

Installed the plugs and torqued them to 120 in-lb. Set the engine on the mower, bolted it to the frame, topped up with oil, lifted the plug wires to spin it a bit with the starter to prime the oil pump and fill the new filter. Cranked it sans muffler, and that thing sounds WICKED without the muffler. Sounds like a little Harley that hasn't grown up yet. Ran it til warm, shut it off. hit the starter with the throttle bottomed out (slow/idle speed), and it fired on the first compression stroke. I was VERY impressed at what a minor tweak on the valves did. Still got a little bit of an occasional sputter on #2 cylinder at idle, with an occasional nice hot blue flame coming out the pipe with no muffler on it. It's a 2012 engine, nearly 10 years old, so I guess I can't complain too much considering the amount of dust I cleaned off it where I can't wash it regularly. It runs absolutely clean, no smoke of any kind unless I choke it pretty hard when it's cold. I may put a new carby on it next year, but it's running well enough to just live with it as is.

I have to say, leaving it outside for all but the last 4 months of its life did it no favors. I should get a lot of life from this machine if I don't detonate the hydrostatic transmission first. It has nearly 200 hours on it, and I use it on about 1.5 acres for grass and LEAVES. LOTS OF LEAVES. I can't even make a full swath around the yard without stopping this time of year. The tranny's howling pretty loud lately. It's apparently not a serviceable item, or so the OM says. Can't find any leaks, and there's no fill plug for topping up the hydraulic fluid. Not sure what to put in it if I found the plug. I don't like noisy hydraulic pumps, though. Doesn't seem to be short on torque/power, but it uses so little of the engine HP anyway, not sure I would notice a significant loss. Gradual losses over time are hard to gauge.

Thanks for the reference materials and links from those of you that post them. Was pretty easy to identify my engine and get the right parts for it the FIRST time, and they were OEM parts except the filters. They may be, but they came in generic (plain) wrapping with no B&S label at all. Everything else was individually wrapped in B&S logo bags.

All in all, pretty easy job. The cleanup to get the gunk off it before I cracked open the block took longer than the actual repair. Mower engines get NASTY, especially with a yard like mine (more hard clay and deadpan than grass). I probably knocked at least 5 pounds of dirt off this thing because of the prior oil leak accumulations. Pretty amazing how well oil runs up hill when there's a bit of dust involved.

Anyone tried tearing down an MTD hydrostatic gear box? How'd you fare, and was it worth the trouble?
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