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Old 08-01-2009, 05:36 AM   #1
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Default More engine troubles... Help please!

Hey, further to my Hyper 21 engine troubles last time, got a new one today. My Hyper 7 with a hyper 21 engine just came back from the hobby shop with a new piston/sleeve. So we're running it in this afternoon and for some reason there is a problem with the pull start.

It seems to "slip" while im trying to start the car. If i slowly pull the cord the piston will come to the top then "pop" as it passes pinch point, but then as i keep pulling the cord the piston normally doesn't move (i can see the fly wheel not moving)... it does however sometimes "grab" as you keep pulling but this is very rare. If i remove the glow plug the cord moves the piston perfectly... and if i half undo the glow it will also work fine... but with the glow plug secured into the head button, the cord "slips" again.

My hobby shop told me to pull off the pull start and clean it. I pulled it out and cleaned up the oil using tissues and a rag. I cleaned the pull start rod thing, the bearing thing in the middle of the pull start, removed backing plate, cleaned the brass sleeve type thing in the backing plate, cleaned the fan thing inside that connects to the Conrod/cam shaft, and cleaned some bearing thing in there too.

put it all back together and still not a goer. Anyone have any any suggestions? Please let me know.

Cheers for the help.
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Old 08-01-2009, 05:54 AM   #2
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new p/s means it is tight. Heat it up with a heat gun then try


you could also loosen the plug just a hair when you start it too.


you didn't put the piston in backwards did you?
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Old 08-01-2009, 06:02 AM   #3
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I didn't put the piston in... my hobby shop did... but from what i saw with the back plate removed it looked right... also... this is the 4th tank running on this new piston/sleeve... the piston/sleeve is a lot looser now than it was when it was new... never had this problem before... only started this afternoon... i was running it in using the heat cycle method... this afternoon ran for 5 mins.. stopped.. started again fine.. stopped and started for another 3 times... went to restart it for the 5th time and the problems started.

I will try heating it though... i normally start it that way since it's "new" engine and it's easier to start after heating... i haven't tried it since i started having the problems so tomorrow morning will give it a shot.

Last edited by LordAnubis; 08-01-2009 at 06:13 AM.
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Old 08-01-2009, 06:12 AM   #4
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really wish i could be more help. It's very hard to diagnose engine trouble over the net. I can't imagine that they put it back together with a bad rod or bearings. Also alot of the times at least with me anyway, i would think my engine was bad when i needed just a little more time with it to realize it's not the engine it's me lol!
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Old 08-01-2009, 06:13 AM   #5
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also i know i couldn't trust my lhs to repair my engine correctly yours might be different. Personally after thinking about it, you should bring it back to them and ask the wtf??
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Old 08-01-2009, 06:25 AM   #6
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I had a problem like that a while back and it turned out to be the one way bearing in the pull start. There was a tiny crack in the one of the rings that holds the bearings tight to the shaft and when the motor was under no load it worked perfect but as soon as you put it up against full compression it would flex that crack and become loose on the shaft not allowing the pull start to spin the motor. I would check that out.
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Old 08-01-2009, 06:27 AM   #7
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I'll most definitely do that... however tomorrow is Sunday and they aren't open... i'll take my car along to a local track tomorrow and ask the people there for some assistance... Just thought i'd get some feedback from people in here... also to find out if this is something routine that happens.
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Old 08-01-2009, 06:32 AM   #8
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get a roto start ...at least then all you will have to deal with is a 1 way bearing going out every now and again ...just my .02 and prolly get one on ebay for cheap ...or get a different motor mount and a starter box ..your rc exp will be infinitely more enjoyable
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Old 08-01-2009, 06:34 AM   #9
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mdbrowdy1, cheers for the advice... I only found one "washer" inside the pull start... It was a washer on the inside of the backing plate... basically a little black piece of metal between the backing plates brass sleeve, and the bearing in the fan thing. I had a good look at it and it didn't have any cracks on it. I though maybe the thing was a curved washer, so i put it in one way, and tried it the other way too and both with no success. Perhaps I need another washer?
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Old 08-01-2009, 06:40 AM   #10
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Quote:
Originally Posted by zixxer View Post
get a roto start ...at least then all you will have to deal with is a 1 way bearing going out every now and again ...just my .02 and prolly get one on ebay for cheap ...or get a different motor mount and a starter box ..your rc exp will be infinitely more enjoyable
zixxxer cheers for the comments... i was gonna mention in my first post for no one to say "get a roto start/starter box" but i forgot !!! To be honest i jsut think it adds more drama... though i certainly will consider it if i need to replace my pull start. I quite enjoy my pull start... i've never had a problem... my car generally starts on first or second pull. if not, then there's something wrong.

On this maintenance note... i have a suspicious feeling that rc companies don't make any money of selling cars... but make 99.999% of their money from selling parts !!!! I sure have a paid a fair bit for parts (this includes fuel, glow plugs etc)

Anyway thanks for the info folks keep it coming !!!
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Old 08-01-2009, 07:54 AM   #11
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Quote:
Originally Posted by LordAnubis View Post
zixxxer cheers for the comments... i was gonna mention in my first post for no one to say "get a roto start/starter box" but i forgot !!! To be honest i jsut think it adds more drama... though i certainly will consider it if i need to replace my pull start. I quite enjoy my pull start... i've never had a problem... my car generally starts on first or second pull. if not, then there's something wrong.

On this maintenance note... i have a suspicious feeling that rc companies don't make any money of selling cars... but make 99.999% of their money from selling parts !!!! I sure have a paid a fair bit for parts (this includes fuel, glow plugs etc)

Anyway thanks for the info folks keep it coming !!!
I see your starting to kech on. More than likly it the one way bearing. Shop around for it 'cause I found they all use the same one. Just find the best price and make yourself happy.
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Old 08-01-2009, 08:02 AM   #12
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best money ever spent and yes they do make money on rtr parts and hop ups ...prolly more like 100% of there money haha ...heres some linkys

http://www.nitrohouse.com/catalog/pr...ducts_id=12742

http://www.nitrohouse.com/catalog/pr...ducts_id=12738
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Old 08-01-2009, 08:05 AM   #13
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Hey mate,

Its almost a certainty that it is your one way bearing (they tend to go quickly). Take off the pull start, replace the one way and you should be good to go. Although many look similar, some are slightly different in length so be careful. You can try cleaning it with metho and then spraying it LIGHTLY with WD40. This might help in the short term but you will eventually need to replace it.
Hope this helps!
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Old 08-01-2009, 05:29 PM   #14
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Question. The one way bearing resides in that fan thing right? If so can you get a new bearing only, and replace it.. or does the new bearing come with the fan thing as well?
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Old 08-01-2009, 06:03 PM   #15
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Yes sir. You can get it. Try to see if there is any numbers on it. Give it a good cleaning and look close. If there is, you can go to any bearing store and they will help track one down. You might have to buy five or more to get a good price, but you could sell some to you buddys and recoup some $. It's one of those things that you have to take out and clean often. Thats why most people use roto starts and bump box's. Less work/more play. After the spring goes weak and the cord lays on the pipe and burns up, then you'll upgrade. It's just one of the things that make this hobby so much fun,trying to get over cheep. Just losen up the purse strings and have fun.
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