Think I bent the crankshaft on the mower

[Brons2]

I hit a fairly large root and bent the blade. I put a new blade on but now the mower shakes like no tomorrow when it runs. It starts up on the first pull still even after sitting for two months, but the vibration is pretty bad Honda HRR216 with GCV160 motor.

Any suggestions?

 

[Panzerman]

You just probably sheared the keyway. It takes a lot to bend a crank and if you did, it probably wouldn't even run and would bind up. Check your keyway. I did the same thing and it shook really bad. (I hit a 4x4). all was, was the keyway.

 

[Donald]

Pull the spark plug wire and tip the mower up and rotate the blade around. If the shaft is bent its not going to look right as it goes around (use a glove).

You could have bought an unbalanced blade.

Time for a Chonda engine from HF.

 

[rustytoolss]

We don't have much lawn mower problems in Ohio this time of the year. But if I were to clear my lawn with my SnowBlower, I may run into the wife's plants.

 

[Brons2]

Originally Posted By: Panzerman
You just probably sheared the keyway. It takes a lot to bend a crank and if you did, it probably wouldn't even run and would bind up. Check your keyway. I did the same thing and it shook really bad. (I hit a 4x4). all was, was the keyway.


I'm not familiar with the "keyway", what is that?

 

[Brons2]

Originally Posted By: Donald
Pull the spark plug wire and tip the mower up and rotate the blade around. If the shaft is bent its not going to look right as it goes around (use a glove).

You could have bought an unbalanced blade.

Time for a Chonda engine from HF.


Good ideas, thanks. I hate to buy another blade but if the first one is good and the motor is bad then I can always keep the 2nd blade for a while until I need it.

How much are these "chonda" engines?
(never mind, I see them on the HFT web page. looks almost identical.)

 

[Lubener]

There is a key between the crankshaft and the hub which the blade mounts to. There is also a flywheel key which is probably damaged but won't cause the shakes. I bet you did bend the crankshaft which you can do a visual inspection. I would replace the mower if that happened instead of a new engine.Mowers are getting very affordable.

 

[Eddie]

Crankshafts can be straighten if not too bad. Call a shop before investing in a new motor or mower. ed

 

[Cujet]

I use a 5 pound sledge and a dial indicator to straighten the mower crankshaft. Works perfectly.

 

[crazyoildude]

have the blade balanced and check the key that is made to shear if you hit something. Chenkshafts are not usually that easy to bend.

 

[Brons2]

Originally Posted By: Lubener
I would replace the mower if that happened instead of a new engine.Mowers are getting very affordable.


This is a $400 Honda mower and everything is in excellent condition, other than the vibration problem. Actually the mower runs and cuts grass great still, the vibration is just super annoying.

I'd much rather fix the engine or re-engine with the HFT motor for $120 then buy some piece of ____ low end mower.

 

[Merkava_4]

Why not replace the crankshaft?

And while you're at it, replace the crankshaft oil seals and install new piston rings.

 

[Lubener]

The Honda engine is what makes that mower great. Replacing it with a Chinese replacement will make that a lesser mower. Don't attempt to have a crank straightened. The metal will be weakened and that's something I wouldn't want when a blade is spinning at 3000 RPM's.Eventually, using this mower as is will probably crack the mower housing. Been there, done it.

 

[Donald]

So pull the blade off and the hub, look for keyway on shaft and hub, and a key. If all look good, replace the blade and turn it by hand looking or measuring how far away from the deck the blade is, Are both sides the same?

I am not sure about straightening the crankshaft. Maybe it works.

I would either get the crankshaft replaced or a Chonda engine. A new Honda engine would be as much as the mower I would bet.

 

[01rangerxl]

A lot of Honda GCV engines bend the crank if there is a significant blade impact. SOMETIMES you get lucky and it actually shears the key like it should, but a lot of times the crank is bent. Even if you see shearing on the key (a lot of times they shear just half way and don't completely split), the crank may not be okay.

If you're comfortable doing internal work on a small engine, any OPE shop that deals with Honda should be able to get a crank quickly if they don't have one in stock. We kept them in stock at the large OPE repair/refurbish company I worked at.

I know one older guy that straightened a Honda GCV crank with a hammer, LOL.

 

[Panzerman]

Iam talking about the key way on the flywheel. It will run and it will shake and vibrate. I seriously doubt you bent the crank. I would have to see a crank bent to believe it. I just don't think the horsepower is there. It will shear the key way off or just stop.

 

[Merkava_4]

Originally Posted By: Panzerman
Iam talking about the key way on the flywheel.


If the flywheel key is sheared, the engine will not run. It will be out of time if the flywheel key sheared.

 

[old1]

I would bet money the crank is bent. Have seen many, many, many of them in my 50 years of repairing mowers. I used to straighten them. Have a jig to do it. Stopped doing it many years ago though when the society got so sue happy. Nobody that I know of in the state will do it for a customer anymore. I have straightened some that were bent so badly that the engine wouldn't even turn, and never had one break for me while straightening or in use afterwards. I still have the jig, and use it to at least partially straighten the crank if replacing it, because if bent to bad the sump won't come off the crank. If you can do the work yourself, parts probably not to expensive, but if you gotta pay professional labor rates, may not be feasible.

 

[Lubener]

I seen one bent so bad that the deck was busted up because the engine was shaking so bad. Anyone who has never seen a bent crank has not had much experience working on small engines.

 

[Lubener]

Originally Posted By: Panzerman
Iam talking about the key way on the flywheel. It will run and it will shake and vibrate. I seriously doubt you bent the crank. I would have to see a crank bent to believe it. I just don't think the horsepower is there. It will shear the key way off or just stop.


That blade is spinning at 3000 RPM. You don't need much horsepower to bend the crank at that speed.