| Author | Message | ||
     Torquehd |
Crappy way to start the mowing season. After a new battery, oil, plug, fuel lines, my riding mower started on the first crank. Mowed half the yard then it died. Cranked the starter. THUD. Will not turn over.   Looks like the valve keeper let go, the valve fell into the cylinder, and got impounded into the head.... Hope I can find parts. Do you think I should tear the bottom end open? The piston has a very small gouge but I think I can knock down the bur with some sandpaper and reuse it? The Cyl wall looks just fine and (with the top end off) the bottom end turns over with no issues. Looks like a new head, complete, will run around $170 online. | ||
| Greg_e |
Weld it or fill it with aluma-weld, replace valve, run it. It's a lawn mower, no one is going to die if it stops working while running. | ||
| 86129squids |
Buy a couple of goats. Yard done, free milk and cheese, then a BBQ after a while. | ||
| Ourdee |
I would just cut the burr off with a wood chisel by hand. ie. no hammer. Throw in a new valve and lap it in. Wipe it out. Rub oil on the cylinder wall, and button it up. GOLDEN. | ||
| Griffmeister |
Just be sure that the piston comes up to the top of the cylinder or else you may have a bent rod that will blow apart on the second half of the lawn. | ||
| Torquehd |
Thanks for the advice guys. The valve impacted the valve guide so I'll have to check it out further tomorrow. Not buying a whole new head would be a lot friendlier on the bank account. I hate goats but I'll eat them if I'm hungry. However, I LOVE a lamb steak  The wife and I wanted to get a few sheep prior to moving across country. We're renting now but that's in the long term plans for when we get to move back home to Wa. (Message edited by torquehd on April 14, 2018) | ||
| Greg_e |
If the valve guide is shot, that might be an issue. What kind of motor is it? Could you drop a brand new one from Harborfreight in there? | ||
| Torquehd |
Yeah it's prettty jacked.  I've never dealt with valve-related damage before so I'll listen to whatever advice you guys have. I could use a rotary tool and remove the portion that got smashed up into the valve tract. But it seems like that part keeps the valve straight, and having a mangled guide would cause problems in a short time. I think a new head might be the best answer. | ||
| Akbuell |
Were it me, I would first check and confirm that the con rod is not bent, and the crankshaft is still straight. Sudden stoppages like that send massive forces through the entire rotating mass, possibly in excess of structural strength. If that is all good, next would be 'is the valve guide replaceable'? It may not be, and a new head would be, IMHO, the most efficient response. If the guide is replaceable, heat and special drifts (punches) would be needed . . . . Hope this helps, Dave | ||
| Xbduck |
Figure out what motor you have and what head will fit it. Then go to metal re-cyclers or the local landfill and see what you can find on the cheap. The re-cycler will charge scrap weight and the landfill people usually don't care what goes out because they know it will be back later. | ||
| Ourdee |
Craigslist a used mower for under a hundred and swap motors. | ||
| 86129squids |
 Actually, a very good idea! Every time I head to the recycling place, while I'm waiting in line, I get out of the truck and just look around. It's amazing what people just throw away... it's worth asking the guys working there what they might know about that could be viable. I've seen a few fairly decent looking gas grills that could be had for scrap weight. Oftentimes you'll have a local small-motor fixit guy who should have what you need, for short money. Sometimes it's fun to poke around at a junkyard, not so much a landfill...  | ||
| Greg_e |
That doesn't look like it actually hit the guide, just the casting around the guide. Should clean right up with a grinder. | ||
| Ourdee |
I have a chuck off a drill mounted on a T-handle that I use for that kind of work. I just chuck up a proper size bit and work it by hand. | ||
| Strokizator |
With luck you live near a small-engine guy who can knurl and ream the valve guide for a couple of bucks. Otherwise, the tools to make the repairs cost more than a new Chinese engine | ||
| Xbduck |
At the landfill in my county the metal parts and pieces are kept separate from the general landfill mass because it is sent out to a recycler. I have seen a number of motorcycle and atv frames, push lawn mowers and riding mowers. Everything short of cars and trucks. | ||
| Torquehd |
I currently live nowhere close to a landfill, only a transfer station. My previous residence was the same, but at least there they had a decent lot at each station - computers, glass, metal, wood, yard waste, etc. Here, everything just gets chucked into a trailer and hauled across the state. Checked craigslist. I'd be better off buying a new head. Think I'll play with the dremel tool and see how much further I can mess it up. Then buy a new head if needed. | ||
| Greg_e |
You really have little to lose by working on it, you already consider it junk so how much worse can you make it. It either works when you are done, or it is still junk. The most you'll be out is time and the valve parts (valve, spring, keepers, seal, spring cap thing). | ||
| Sifo |
Just curious what brand this is. Honda? It's not the typical B&S flat head design. I agree with those who are saying do what you can to drop a new valve in on the cheap. Clean up the path for the stem, lap the valve/seat, smooth the piston, and put it back together. If the valve stem feels loose in the guide compared to the other valve, consider finding a small engine repair shop that can knurl and ream the guide back to spec. If the bottom end blows up, you have little invested. The chances of it working out are fairly good. | ||
| Torquehd |
Frustrated. Replaced the valve, lapped the face, reassembled. Cranks but won't start. It cranks, it sparks, it sucks, it blows. It acts like it's not getting any fuel. When you pull the plug or the exh manifold and hold your hand over the hole, there's no gas vapor being pumped out with the air. However, when I pull off the air filter housing and crank it over, I have a healthy amount of fuel vapor spitting back out the intake.... I wonder if a bent rod would somehow do that. I can't make sense of it though. | ||
| Gregtonn |
Check the compression. G | ||
| Sifo |
I had a lawnmower doing similar stuff to me. Every once in a while it would start, run poorly, the die again. Couldn't make heads or tails of it. Turned out that a couple of teeth had been knocked off the cam shaft and it would randomize the cam timing. Plastic cam gear and cam lobes! | ||
| Akbuell |
Something to try: If you have a rocker box cover, so to speak, take it off and turn the engine over by hand, plug out. If the valves are working, turn the engine over until the intake closes, then continue to TDC, using a straw or similar to find TDC. Blow air into the spark plug hole with an air hose. You may need to hold the crankshaft. Listen and feel for air escaping. If the valves are not opening and closing, you will know before you need the air hose. If they are, air hose air from the exhaust means the exh valve is not sealing. Through the intake means that valve is not sealing, and from the crankcase vent (or oil fill hole) then the piston/rings are the problem. Hope this helps, Dave | ||
| Natexlh1000 |
The springs on these things are silly weak as compared to our H-D derived engines. I attempted to adjust the clearances on my snowblower last year and couldn't tell the tappet was opening the valve by feel. No compression at all. I had to trial and error it to get it right again. That may be what's happening here. | ||
| Griffmeister |
Of course if the engine stopped suddenly, like it would when the head of the valve stops the piston, it may have sheared the flywheel key. This will throw it out of time enough so it’ll never start. | ||
| Natexlh1000 |
Oh yeah the flywheel key is probably sheared. I popped a few of those in my days just mowing the lawn/stumps/rocks. | ||
| Torquehd |
Victory! And I'm an idiot! I adjusted the valves to zero-lash, which was AND, I didn't have the valve keepers fully seated, and I dropped a valve AGAIN but, this time no harm was done I just had to tear it down and put it back together the RIGHT way.  She's nothin fancy and a Craigslist special, but it beats the HECK out of mowing the whole yard with a weed eater! (which also broke - just my luck!). (Message edited by torquehd on July 06, 2018) |
