Small engine shaking too much when running, Why?

[GoceKU]

Now all you need, is to find a matchbook.

You correct on that one Mike, i need to find a matchbook and light it on fire, for all the time lost and all the aggravation. The points are set correct everything is as per the service manual, i'm starting to think this engine may be faulty from the factory in because of that is seen so little use.

 

[juiceclone]

U might lookup whether this model has a history of imbalance? Also, is there a possibility the flywheel is not the correct one, subbed by a previous owner? Maybe check with manufacturer for part no. That level of shaking requires some real explanation. I see that model Tecumseh has flywheel options with/without ring gear, and ally or composite plastic/ally construction. Fins seem to be "set" in plastic.! Single missing fin could be significant.

 

[rgray]

The carbs without adjustable needles for the main jet are sometimes lean. That will cause the engine to surge up and down.
The last big ethanol push here caused a lot of this trouble the carbs are lean as possible in the first place then add 15% ethanol fuel and they are to lean and surge up and down.
Never seen one that would "walk" so I would suspect there is a different imbalance also.
As far as being to lean... I take miniature drills and gauge the main jet hole, then drill to next size and see if the surging is then stopped.
If you go to big they are easy to solder closed and redrill.
There is the argument that the jet hole is an orifice and not simply a hole.... very true and if soldered closed and redrilled it will usually require a larger hole to match the original jetting as the hole ends up longer. You can use a larger drill to keep one end length in check, but the other end is not accessible.

 

[Silverbullet]

Your sealed jet carb isn't adjustable, as others are saying a larger jet hole may help. Your points call for .020 , the only other check is the the valve clearance between the valve and the tappets. There they call for .010 each. You might try the can gas they sell , it's usually two cycle mix but it's high octane and if there's any varnish left it'll clean where you can't. Did you change the condenser along with the points . And did you wipe the contacts after setting.

 

[David S]

sure sounds like an imbalance due to something major. It doesn't have a two piece crank that has slipped?

David

 

[GoceKU]

Your sealed jet carb isn't adjustable, as others are saying a larger jet hole may help. Your points call for .020 , the only other check is the the valve clearance between the valve and the tappets. There they call for .010 each. You might try the can gas they sell , it's usually two cycle mix but it's high octane and if there's any varnish left it'll clean where you can't. Did you change the condenser along with the points . And did you wipe the contacts after setting.

Here we have 95 octane, 98 octane, 100+ octane, on the pumps, i have 100+ octane fresh fuel in it, the fuel and the fuel tank is clean, the condenser and points are still the same, i did vipe the points after setting them, i don't know if i can upload a video here just to show you how much this little engine is shaking and how much it walks on the floor, only thing i can think to compare it to is rock separating screens at a rock quarry.

 

[juiceclone]

sure sounds like an imbalance due to something major. It doesn't have a two piece crank that has slipped?

David

Hmmm .. never considered the possibility of a split type of crank ...only seen those on single cyl motorcycles. If the crank was not assebled or repaired correctly...or slipped? that would imbalance everything plus wear all bearings.

 

[Silverbullet]

Oh I know they walk , not many will sit still unless there real heavy cast iron. The only thing I do know it should run even, and better when mounted with the generator and frame. Tecumseh engines are real dancers always were till mounted , that style with a cast flywheel have counterweights on the larger motors . It's the flywheel which is bouncing it . With out that it wouldn't be start able.

 

[GoceKU]

Oh I know they walk , not many will sit still unless there real heavy cast iron.

See if this is normal, link: https://streamable.com/mjbas

 

[dtsh]

That looks perfectly normal to me, just need some rubber pads on the underside to give it some grip to the floor and absorb some of the vibration.. Such a small unit doesn't have enough mass to soak up that much vibration.