# Engine vibration **URL:** \ **Category:** GEM Forum\ **Created:** [February 8, 2025, 10:34pm UTC](https://community.electricforum.com/t/engine-vibration/28853 "2025-02-08T22:34:06Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![Bolanger](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/bolanger/32/4184_2.png) [@Bolanger](https://community.electricforum.com/u/Bolanger)\ **Post date:** [February 8, 2025, 10:34pm UTC](https://community.electricforum.com/t/engine-vibration/28853/1 "2025-02-08T22:34:06Z")
Remove engine and replaced tach magnet and connection. Replaced the rubber engine shaft spacer. Runs great but if I let off accelerator at 25mph get sort of a vibration noise. I’ll check bolt tightness tomorrow. Any suggestions after that ---
**Author:** ![Bolanger](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/bolanger/32/4184_2.png) [@Bolanger](https://community.electricforum.com/u/Bolanger)\ **Post date:** [February 11, 2025, 4:58pm UTC](https://community.electricforum.com/t/engine-vibration/28853/2 "2025-02-11T16:58:11Z")
Rubber bumper…fixed it ---
**Author:** ![AssyRequired](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/assyrequired/32/7621_2.png) [@AssyRequired](https://community.electricforum.com/u/AssyRequired)\ **Post date:** [February 11, 2025, 5:13pm UTC](https://community.electricforum.com/t/engine-vibration/28853/3 "2025-02-11T17:13:49Z")
I’m confused. In your first text (3 days ago) you said you replaced the rubber engine shaft spacer. Yes, that is always the first Go-to with the symptoms you posted. In general, if you still have vibration on decel, you may be looking at excessive spline/coupler wear and in need of a new input shaft next. But then you came back and said you had to replace it again and now it’s fixed? Did you use a different bumper? BTW- It is actually a good idea to also apply a dap of assembly paste on the splines before assembly. ---
**Author:** ![Bolanger](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/bolanger/32/4184_2.png) [@Bolanger](https://community.electricforum.com/u/Bolanger)\ **Post date:** [February 11, 2025, 8:56pm UTC](https://community.electricforum.com/t/engine-vibration/28853/5 "2025-02-11T20:56:00Z")
Ok…made an inaccurate post so deleted it. Few years ago I bought some bumpers that had the same edge surrated to match the spline cup on the differential. I had forgot that I used one before and had the same noisy result. Rather than throwing it out i saved it and in error used it on this project…with the exact same results. Went down to the local GEM dealer and got a OEM replacement and all is good again. When I held both bumpers up together the serrated one was noticeably thinner. Just passing on my experiences. ---
**Author:** ![Bolanger](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/bolanger/32/4184_2.png) [@Bolanger](https://community.electricforum.com/u/Bolanger)\ **Post date:** [February 11, 2025, 9:00pm UTC](https://community.electricforum.com/t/engine-vibration/28853/6 "2025-02-11T21:00:45Z")
I think I remember a post years ago about someone suggesting placing a dime behind the bumper. Perhaps it was this product. Anyone heard of this ---
**Author:** ![Cformony](https://avatars.discourse-cdn.com/v4/letter/c/b19c9b/32.png) [@Cformony](https://community.electricforum.com/u/Cformony)\ **Post date:** [February 11, 2025, 9:27pm UTC](https://community.electricforum.com/t/engine-vibration/28853/7 "2025-02-11T21:27:49Z")
I’m still trying to figure out if it’s a vibration OR a noise… ---
**Author:** ![Bolanger](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/bolanger/32/4184_2.png) [@Bolanger](https://community.electricforum.com/u/Bolanger)\ **Post date:** [February 12, 2025, 7:11pm UTC](https://community.electricforum.com/t/engine-vibration/28853/8 "2025-02-12T19:11:03Z")
This post has been a valuable lesson on getting all your ducks in a row before posting. Sorry to all…won’t happen again. To answer the question 90% noise 10% vibration ---
**Author:** ![JarJarJava](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/jarjarjava/32/15158_2.png) [@JarJarJava](https://community.electricforum.com/u/JarJarJava)\ **Post date:** [February 13, 2025, 9:05am UTC](https://community.electricforum.com/t/engine-vibration/28853/9 "2025-02-13T09:05:13Z")
> [@Bolanger](#): > > Few years ago I bought some bumpers that had the same edge surrated to match the spline cup on the differential. I had forgot that I used one before and had the same noisy result. Rather than throwing it out i saved it and in error used it on this project…with the exact same results. Went down to the local GEM dealer and got a OEM replacement and all is good again. > When I held both bumpers up together the serrated one was noticeably thinner. Just passing on my experiences. I’ve seen similar behavior with the thinner Club-Cart “toothed” bumpers in certain situations. Sometimes they have issues right off, other times it takes 30-40 miles. Once in a while they worked about as well as the heavier Polaris smooth bumper. My lot sample of 8 or 9 wasn’t big enough to pin it down to a particular set of conditions I could have repeatable results. Amount of wear obviously did play a part, such as how long the differential input shaft was / how deep it went into the collet on the motor or how much backlash (how tight the spline fitment was), bearing play, etc But which ones, I can’t say. A few times a motor or input shaft was changed, Once it made no difference, old motor - old shaft - new club cart bumper, same as old motor - new shaft - another new bumper, same as new motor - same new shaft - yet another new cc bumper. until I put a polaris bumper in, then it finally shut up … /shrug Good grease usually helped, Too much and it could hydraulic the pair and either the motor end bearing or the input bearing could take a hit. **Club-cart bumper:** ![club cart bumper](https://canada1.discourse-cdn.com/flex030/uploads/electricforum/original/3X/7/4/74164eb94339f68cf9cb5e1531121e12761ba232.jpeg) **Polaris OEM bumper:** ![polaris bumper](https://canada1.discourse-cdn.com/flex030/uploads/electricforum/original/3X/9/0/90844b060c919fb7f9f8802dfb5bd68eb6748a65.jpeg) @Old_Houseboater once mentioned you can use a dime, I never did try that, ---
**Author:** ![Old\_Houseboater](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/old_houseboater/32/544_2.png) [@Old\_Houseboater](https://community.electricforum.com/u/Old_Houseboater)\ **Post date:** [February 14, 2025, 3:32am UTC](https://community.electricforum.com/t/engine-vibration/28853/10 "2025-02-14T03:32:23Z")
The piece you call the “Club Car” bumper is actually for a 10 spline set up. It can also be used in a 19 spline equipped configuration. You cannot use the smooth in a 10 spline configuration. Noise/vibration comes when the shaft and coupling splines are worn out. You can get by with one spline worn and one good spline with a new bumper… If both splines are worn you cant win. Adding a dime is an iffy way to get a few quiet miles but you take a chance of taking out the small bearing on the end of the input shaft. If you think a dime is good how about a penny. A penny is almost guaranteed to burn out the small bearing. how harmful is that.? Broken pieces of bearing just don’t fit between gear teeth. It makes GLORIOUS destructive sounds though. I have some replacement gear boxes in stock.