1650 vibration after installing new style mounts

Sun Jun 26, 2011 9:53 am

Hope someone out there can offer me some advice. I have a 1976 (built date) 1650 which I have had since the late 80's. It's a great workhorse, and cuts over 2 acres of not your "smoothest" lawn, and well worth maintaining. Issue is I noticed a different "feel" to it and found that the rear motor mounts were both worn out. When I went to my local
IH dealer, he had mounts, but they were of a different style then the last ones I put on quite a few years ago. The previous mounts (and the original), the upper and lower mounts were the same style (cone shaped), but the new mounts have the same cone shaped one for the bottom, but the upper mount is shaped like a hollowed out hockey puck, with 2 washers that fit into the hollow. They went in fine, but the issue I am having is that since I changed them, at mid rpm, it vibrates like crazy(this was not the isssue before I changed them). It sounds like all the sheet metal on the tractor is going to shake right off. At idle and high speed it is fine. I removed the drive shaft, thinking the coupling might have been the issue, but still have the same issue. The install sheet with the mounts says to torque to 100 inch pounds and NOT to over torque. Have re-torqued to 120 inch pounds, thinking this might help, but issue still there. When I contacted my dealer, he said that he saw this same thing once before, and added that "he didn't like this style of mounts". Not very encouraging.
Can anyone offer me some advice I am desperate here.

Re: 1650 vibration after installing new style mounts

Sun Jun 26, 2011 11:47 am

Instead of torqueing the bolts to the specks the instructions list, try backing the nuts off until there is just a thread or two showing thru the nut (self locking nut). Others have had good results installing them like this, but that 16 hp engine is going to shake some. If you are trying to mow with the engine running at mid range, you will get more shake at that RPM (I know , it didn't shake that much with the original type mounts). Kohler says the engine should be run a full throttle when mowing (or with any load on the engine) mainly to get enough cooling airflow across the engine, and to get the deck blade speed where it should be. At full throttle when mowing, that engine should be as smooth as it is going to get with the new type mounts. You will find the statement to "run the engine at full throttle" in most, if not all of the Operators Manuals. In fact, it is in the 1975 dated Ops manual for the 800 to 1650 models at least 3 times the 3rd time under the heading "Starting the Mower", quote "With the engine running at idle speed, start the power take-off clutch, Advance the throttle to to full throttle" end quote.

You can also try to find some used "original type" mounts. Normally the upper mount is never worn, even when the lower one is shot, so if you can find 8 used "uppers" (upper and lower are the same) you can try those. There are several used Cub Cadet parts venders around that will probably have what tyou need. Other owners have used 4 good uppers on the bottom and used some Moog (part number 5220 I think) automotive stabilizer bushings on the top. They are shapped a little different, but work fairly well, at least on the lower HP engines.

Along with "Hogg", "Harley" and others, a Harley-Davidson motor cycle has had the nickname "The Milwaukee Vibrator", but Kohker built their own version when they built the 16 HP "K" series engine...........

Re: 1650 vibration after installing new style mounts

Mon Jun 27, 2011 7:51 am

Thanks for the advice, and insight, I really appreciate it. I'm aware of the need to run the motor at full throttle in order to get advantage of optimum cooling, but use the midrange speed if stepping off the tractor for a couple of minutes, and during cool down. Anyhow, I will try backing off the nuts and see how that works. Will let you know how I make out. Thanks again for the help.

Re: 1650 vibration after installing new style mounts

Tue Jun 28, 2011 10:45 am

Ollie, here's my take: I did a restoration on my 1200 Cub Cadet about a year ago. I had to replace all of my engine mounts due to the bad wear on what was left of the prior ones.

Apparently the newer engine mount rubber is much harder than the originals. I too had some terrible vibration with my Cub Cadet. Just like Paul suggested, I backed off the lock nut a little bit. I ran the tractor for about 10 hours or so, then tightened the lock nuts just a tad.

Something must be working out as mine are getting broke in a little bit at a time. I know I'll never be totally without vibration - as that is the nature of the beast here. But, it is comforting to know that I don't have quite as much vibration as I've had in the past. :shock:

The thing I really hate about those engine mounts is they are so hard to get to and work with. There really isn't much room in those areas for tightening things up.

Re: 1650 vibration after installing new style mounts

Thu Jun 30, 2011 8:13 pm

I think the new iso bushings can be over tightened too right? I just snugged mine just to zero on the sleeves on my 1200. This is why they have loc nuts.

My 122 12hp cc was vibrating and shaking(engine) I found 4 cracks in the frame under the engine when i removed it. The cracks ran from the securing holes into the frame. I drilled a small hole were the cracks ended and ground out the crack so i could get more weld into the area. I had to grind the new weld flush so the engine sits flat when its bolted in. Now the shake rattle and roll is gone. My first problem was watching the exhaust shaking and i knew something else was wrong besides a carb adjustment.