2 Brand new engines Seize?

I recently bought a 70cc 2 stroke kit from ebay. I got everything installed and when I went to start it for the first time, the engine cycled a few times then seized up. So that my back tire would not turn, even with the clutch all the way pressed. The person I got the engine from exchanged it for me and when I got the next engine, something similar happen. But the second time the engine tried to turn over twice before seizing again.

I do have experience with 2 stroke engines, so the obvious should be known. Like I did mix the oil with the gas properly. Had the fuel valve switched on and primed the carb, with the choke up.

I have yet to get two of these engines to even turn over for me once. Am I missing something obvious or do I just have bad luck. As far as buying junk off
ebay.

Eric T

Andyinchville1 said:

Hmmmm.....Could the chain have bunched up under the cover because of it running too loose or having a tight link?....That can cause the rear wheel not to turn with the clutch pulled in also...

Unusual that the engine would seize up so quickly....I mean within just a few cycles (maybe something like a rod or something broke?)I would guess running straight gas (no oil mix) the engine should last longer than a few strokes (I know because a helper of mine once ran straight gas in a 2 stroke Lawn Boy mower.....actually lasted quite awhile considering no oil....) BUT since you said you did put 2 stroke oil in the fuel I would think it has to be something mechanical....

Andrew

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I will take a good look to see if a chain is bunching up. If this is the problem would not changing the angle that the chain enters the motor relive this tangleing? So that the bunching of the chain would be freed up and then continue normal function of the engine. I would love for that to be the problem, but I doubt it.

Thank you for your prompt response,

ET

Bikeguy Joe said:

A locked up engine will not prevent the sprocket from turning.

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When you get these kits out of the box, is there anything you need to do to the clutch or the engine before you start it? Could this be a clutch issue. I did not adjust the engine in any way out of the box. Just installed, gas/oil and go.

Thank for your help,



ET

I finally got the third engine in. This time the clutch would not engage. I am not good with engines, but started to take this thing apart. With help from another thread on clutch adjustment, I was able to get the clutch working. Seems that the center of the assembly was stuck somehow. I disassembled and turned a few times to release it.

After looking at all your replies (which has been so much help, thanks), I believe that several factors where a problem for me. I installed the engines right out of the box and did not take any links out of the chain. I thought that i could just do this later and wanted to hear the engine turn over. This is the fist and biggest mistake that i think i made and appears to be the #1 factor which i think made both of the first two engines fail. There was way too much slack in my chain. I am not sure if this would factor in, but I am 300 pounds. I am wondering if my weight and the looseness of the chain contributed to the same scenario happening twice.


I am taking this one very slow and will definitely take the links out before trying to start for the fist time. I was thinking and will submit this idea to all of you: Because I have been having problems getting these engines started, can't i just take the cover off the magneto and start the engine with a power drill with a socket on it to rotate to start? This way I can cycle the engine to start without peddling and just keep the clutch pressed the hole time. Get the engine started and tuned. Once everything is working, then starting it up as normal.

I will wait for suggestions before trying...


Thanks for your help,

Eric