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| upper housing Overheating Crisis!!! https://www.mudmotortalk.com/mmt_v2/viewtopic.php?f=6&t=32471 |
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| Author: | littlegarlic [ Mon Sep 17, 2012 5:19 pm ] |
| Post subject: | upper housing Overheating Crisis!!! |
Having some issues with a homemade longtail I purchased a couple of years ago. I'll lay it out in order 1. Last year i noticed grease coming out of the upper and lower bushings. This is a very simple design, one bronze bushing upper and one lower. Always noticed a little heat but not bad. I considered going to a beaing style but everything works well together 2. This summer i ended up deciding to machine new bushings and change out the u-joint. Had trouble getting the u-joint off and had to cut it get it off. Went to tsp and built a new u-joint and machined the bushings to match the originals. 3. Re-assembled everything and greased it up with blue marine grease (I figured it would help keep water out since my shaft isn't really sealed like the newer ones. I was previously using the black lithium) 4. Fired it up and everything looked good. a few minutes into it where the shaft comes out of the housing started smoking. 5. After this happened a few times i swapped out the new upper bushing for the old one. Run time was slightly longer but still got hot as well as the u-joint. Everything looks lined up properly. So............. 1. Wrong Grease? 2. Didn't assemble u-joint correctly? Any info or insights would be awesome, duck season starts in 5 days and i really don't want this thing to blow up on lake michigan! |
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| Author: | SwampDonkey1 [ Mon Sep 17, 2012 6:21 pm ] |
| Post subject: | Re: upper housing Overheating Crisis!!! |
Sounds like you aren't getting grease to that top bushing, Its a tricky situation being that the shaft isn't sealed. I would suggest and auto lubricator but without seals the grease will just run out. Probably the best thing you could do is use a sealed bearing at the top instead of a bushing it allows the shaft to free float without friction. Might take some major modification, but without some type of lubrication on a bushing you are asking to get that thing locked up. -Put up some pictures of the setup and im sure others will chime in... |
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| Author: | stualaska [ Tue Sep 18, 2012 12:08 am ] |
| Post subject: | Re: upper housing Overheating Crisis!!! |
Have you checked to make sure the shaft is running in the center of the bushing? Have someone turn the prop by hand and watch the shaft. It should stay centered. The new universal may have changed the alignment. |
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| Author: | take'emgator [ Tue Sep 18, 2012 5:15 am ] |
| Post subject: | Re: upper housing Overheating Crisis!!! |
motor alignment with the shaft is Key, if its a hair off you'll see friction on the top bushing |
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| Author: | littlegarlic [ Tue Sep 18, 2012 5:27 am ] |
| Post subject: | Re: upper housing Overheating Crisis!!! |
Thanks for the replies! Ya i'm starting to think its the alignment along with a lower grade of grease. Tonight my wife and i are going to pull the shaft clean everything and refill it with new lithium grease, it worked well before so why change. As far as getting the alignment set, should i do that without any grease in the shaft so i can see the amount of play or is it more trial and error, or its there a process for getting it straight? p.s. - stualaska, nice musky! |
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| Author: | Buzz Killington [ Tue Sep 18, 2012 8:56 am ] |
| Post subject: | Re: upper housing Overheating Crisis!!! |
def go back to a thicker grease. it'll help But it does sound like an allignment issue. you'll be able to tell by firing up the engine - run it for a few minutes (3-5) - then touch the tube around the top bushing. If you can hold it more than 25 seconds without the feeling of being burnt - its a lube issue. If its painful hot - alignment. and still possibly a lube issue as well.... |
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| Author: | Mag10 [ Wed Sep 19, 2012 11:58 am ] |
| Post subject: | Re: upper housing Overheating Crisis!!! |
Pull the top bushing out weld a plate to the end of the tube and mount a 2 or 4 bolt pillow block bearing to it. You will never keep a adequate amount of grease in that bushing with gravity trying to pull it out, especially when the grease heats and looses viscosity. The pillow block bearing will have a sealed bearing and will be easliy serviceable. Just make sure you get one that is rated to 4000 rpms or so. Mag10 |
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| Author: | littlegarlic [ Thu Sep 20, 2012 9:05 am ] |
| Post subject: | Re: upper housing Overheating Crisis!!! |
Thanks for all the help. It ended up being the motor had shifted and screwed up the alignment. Once i got it aligned she runs perfect, and actually better than before. I probably will switch to a bearing on the top next year if i keep it that long, I've been eyeing up the 14hp backwater, and 8hp just doesn't quite push it fast enough when you put people in the boat. |
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| Author: | stualaska [ Fri Sep 21, 2012 10:40 am ] |
| Post subject: | Re: upper housing Overheating Crisis!!! |
| Author: | ironman_gq [ Wed Sep 26, 2012 2:02 pm ] |
| Post subject: | Re: upper housing Overheating Crisis!!! |
I had some issues with mine overheating at first, What I did was pull the shaft off the ending and slide it down the drive tube and back up to make sure the bushing had grease in it, then I unbolted the motor base but left the upper support bolted in place (where the drive tube bolts to the motor near the crank) and turned the prop by hand. This actually shifted the engine slightly and seems to have got everything in alignment. My bushing went from smoking hot to barely getting warm after doing this. |
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