Small Engine Repair - HELP!

[Wingnut]

OK, brain trust .... I need advice from someone who understands small engines a lot better than myself. That should include everyone in the known universe besides my little brother - who thinks a wrench is what happens to your back when you try to jump off the couch during a commercial.
I'm 75% finished power-washing my house ... and either overworked that poor 5hp Tecumseh ... or did something worse. I think it got pretty hot working continuously through 4 tanks of gas (so sue me, the vinyl didn't look dirty 'til I started slicing the gunk off). The oil reservoir was actually smoking when I filled the tank the 4th time (I check the oil after gassing each time) and I had to add about 1/2 pint of oil.
So, anyway, it suddenly quit dead about 5 minutes into that last tank ... after gradually feeding me less and less pressure ... and will not start again. It spun and caught ... and immediately died ... and now it just "freewheels" (spins easily when I pull the rope but just buzzes ... like the motor isn't connected to anything.
So ... besides immediately taking it to a small engine repair service ... what can I look for to figure out what's wrong with the little beast (wifie is a bit upset at me for not finishing the house ... fortunately it's the back that's not finished)?

 

[cp1969]

I know this isn't answering your question, but don't mess with it--just go get a whole new engine, or if that's too much of a percentage of the price of a new washer, get a new washer.

It sounds to me like something broke causing you to lose compression. Nothing simple can cause that. You can find out by pulling the spark plug and putting your finger over the spark plug hole while you pull the rope. If pressure doesn't try to force your finger off, the motor is history.

 

[CSAW]

My generator has a 10 horse tecumseh. A couple of years ago I tried to start it and it had no compression. I pulled the head and found the exhaust valve was no longer seating. Did a valve job and it has been fine since. Good Luck.

 

[Wingnut]

burnt exhaust valve was my first thought ... thanks.

not too sure about the azlternate suggestion of throwing away a pressure washer that's been used for 8 hours though ...

 

[Anonymous Poster]

If you remove the sparkplug, you should be able to see the piston and valves, and determine if they are all operating.
Best guess from your description is that one of the valve retainers has broken or fallen off. It happens a lot more frequently than people think, especially on constant speed engines, like generators and pressure washers.

 

[s1120]

Hmmm?/w3tcompact/icons/hmm.gif Sounds like it was running a bit hot. Most entrylevel motors cant realy survive long hard work. Sounds like a burnt valve, of a holed piston. Pull the plug, and see if you have any compression. If not, pull the head and check it out. Good luck.

 

[unaka]

Your valve seat has come out. If you pull the head off, you will see a little ring caught in the valve. You'll see where this ring is supposed to seat itself.

You can fix it short term by pushing the ring back down, and taking a small pointed chisel or something similar and knock tiny dents into the ring. This will cause the metal to expand slightly and hold the seat in place. Unfortunately, this is a short term fix and will not last long.

The bad news here is that you will probably have to get a new engine. Valve seats pop off when the motor gets too hot, and it's very difficult to get them to stay in place after this happens.

 

[StoneHeartFarm]

wingnut,

Don't know about the smaller engines, but the larger Tecumsehs are noted for throwing rods. They have an aluminum rod that rides directly on the crank, when the engine gets too hot, the rod begins to melt and reduces the clearance which reduces the amount of oil between rod and crank, etc.

Pop the spark plug, drop the blade of a screw driver down the hole until you can feel the top of the piston. SLOWLY turn the engine over with your hand on the screw driver and see if the piston is moving up and down. If it is making a normal cycle (up, down, up), then you've probably got a valve problem. If not, you've got a blown engine.

SHF

 

[Anonymous Poster]

you have only used it for eight hours, is it new? then return it as defective. if it is used then you are stuck with the repair replace options as mentioned. my personal favorite is to replace it as after these engines are heat damaged they never seem to run well again even when repaired properly. i would pull the spark plug, to check on piston movement, and compression if there is no piston movement then the repair will cost almost as much as a new engine. check out the northern tool catalog to get an idea as to what a new engine would cost. if there is piston movement and no compression, take the head off and look for the valves to see itf they are functioning as expected, if not you may be able to buy a valve repacement/repair kit for the engine from an authorized dealer in your area.

good luck,
alex

 

[techman]

Based on a bunch of rebuilds that I have done, I would say that the engine threw a connecting rod. If it is a typical all aluminium engine, usually the crank end siezes up and results in the rod breaking. There is about a 25% chance that the engine can be rebuilt, but usually the internals of the crankcase gets trashed by the rod. Even if the case is intact, a new rod, crank and piston may be needed, and the parts and labor don't justify repair. Go somewhere like Northern Tool (http://www.northern-online.com/) and buy another engine. Most engines have standard mounts, so just match the horsepower and shaft dimensions. You could go to a small engine parts dealer and buy a short block and swap all of the required parts and accessories from the old engine, if you are so inclined. You may save $ 50 or so.

FYI these low cost engines have minimal lubrication systems. Some horizontal shaft engines do not have a pump but just use a "dipper" on the end of the connecting rod to dip into the oil and "splash lubricate" the engine. When you run it hard and the oil level gets a bit too low, the engine is history. Adding 1/2 pint could be a significant portion of the total oil in the engine. Also with the low engine hours, the engine is still in a break-in phase, and may have been using a bit more oil than a more "mature" engine. You could try to get a warranty swap if you got it at a big chain.

paul